bims-toxgon 2024-10-06 papers

bims-toxgon

Biomed News

on Toxoplasma gondii metabolism

Issue of 2024–10–06
25 papers selected by
Lakesh Kumar, BITS Pilani

Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labeling.
ATM1, an essential conserved transporter in Apicomplexa, bridges mitochondrial and cytosolic [Fe-S] biogenesis.
Cap-independent translation directs stress-induced differentiation of the protozoan parasite Toxoplasma gondii.
Uncovering malate dehydrogenase: structure, function and role in disease.
Structural Prediction and Antigenic Analysis of ROP18, MIC4, and SAG1 Proteins to Improve Vaccine Design against Toxoplasma gondii: An In silico Approach.
Symmetrical 2,7-disubstituted 9H-fluoren-9-one as a novel and promising scaffold for selective targeting of SIRT2.
Renal Fibrosis: SIRT1 Still of Value.
Sirtuin 1/sirtuin 3 are robust lysine delactylases and sirtuin 1-mediated delactylation regulates glycolysis.
Toxoplasma Gondii in humans, animals and in the environment in Morocco: a literature review.
The new function of FaSRT2-1 protein in energy metabolism: Promoting strawberry fruit quality and ripening.
Inhibition of ACSS2 triggers glycolysis inhibition and nuclear translocation to activate SIRT1/ATG5/ATG2B deacetylation axis, promoting autophagy and reducing malignancy and chemoresistance in ovarian cancer.
Involvement of INS15 in the development and pathogenicity of the zoonotic pathogen Cryptosporidium parvum.
Enhancement of apoptosis in Caco-2, Hep-G2, and HT29 cancer cell lines following exposure to Toxoplasma gondii peptides.
The metabolic sensor AMPK: Twelve enzymes in one.
Sirt2 Regulates Liver Metabolism in a Sex-Specific Manner.
NIPSNAP3A regulates cellular homeostasis by modulating mitochondrial dynamics.
Capturing a methanogenic carbon monoxide dehydrogenase/acetyl-CoA synthase complex via cryogenic electron microscopy.
Parasites revive hope for cancer therapy.
Inositol Hexaphosphate (InsP6) Activates the HDAC1/3 Epigenetic Axis to Maintain Intestinal Barrier Function.
Addressing the Intracellular Vestibule of the Plasmodial Lactate Transporter PfFNT by p-Substituted Inhibitors Amplifies In Vitro Activity.
Quantitative analysis of non-histone lysine methylation sites and lysine demethylases in breast cancer cell lines.
Small molecules targeting selective PCK1 and PGC-1α lysine acetylation cause anti-diabetic action through increased lactate oxidation.
Research advances in protein lysine 2-hydroxyisobutyrylation: From mechanistic regulation to disease relevance.
Asparagine as a Signal for Glutamine Sufficiency via Asparagine Synthetase: A Fresh Evidence-Based Framework in Physiology and Oncology.
Selective inhibition of HDAC class IIA as therapeutic intervention for KMT2A-rearranged acute lymphoblastic leukemia.

mBio. 2024 Sep 30. e0238024

Characterization and functional analysis of Toxoplasma Golgi-associated proteins identified by proximity labeling.

Rebecca R Pasquarelli, Justin J Quan, Emily S Cheng, Vivian Yang, Timmie A Britton, Jihui Sha, James A Wohlschlegel, Peter J Bradley.

  Toxoplasma gondii possesses a highly polarized secretory pathway that contains both broadly conserved eukaryotic organelles and unique apicomplexan organelles, which play essential roles in the parasite's lytic cycle. As in other eukaryotes, the T. gondii Golgi apparatus sorts and modifies proteins prior to their distribution to downstream organelles. Many of the typical trafficking factors found involved in these processes are missing from apicomplexan genomes, suggesting that these parasites have evolved unique proteins to fill these roles. Here, we identify a Golgi-localizing protein (ULP1), which is structurally similar to the eukaryotic trafficking factor p115/Uso1. We demonstrate that depletion of ULP1 leads to a dramatic reduction in parasite fitness that is the result of defects in microneme secretion, invasion, replication, and egress. Using ULP1 as bait for TurboID proximity labeling and immunoprecipitation, we identify 11 more Golgi-associated proteins and demonstrate that ULP1 interacts with the T. gondii-conserved oligomeric Golgi (COG) complex. These proteins include both conserved trafficking factors and parasite-specific proteins. Using a conditional knockdown approach, we assess the effect of each of these 11 proteins on parasite fitness. Together, this work reveals a diverse set of T. gondii Golgi-associated proteins that play distinct roles in the secretory pathway. As several of these proteins are absent outside of the Apicomplexa, they represent potential targets for the development of novel therapeutics against these parasites.
IMPORTANCE: Apicomplexan parasites such as Toxoplasma gondii infect a large percentage of the world's population and cause substantial human disease. These widespread pathogens use specialized secretory organelles to infect their host cells, modulate host cell functions, and cause disease. While the functions of the secretory organelles are now better understood, the Golgi apparatus of the parasite remains largely unexplored, particularly regarding parasite-specific innovations that may help direct traffic intracellularly. In this work, we characterize ULP1, a protein that is unique to parasites but shares structural similarity to the eukaryotic trafficking factor p115/Uso1. We show that ULP1 plays an important role in parasite fitness and demonstrate that it interacts with the conserved oligomeric Golgi (COG) complex. We then use ULP1 proximity labeling to identify 11 additional Golgi-associated proteins, which we functionally analyze via conditional knockdown. This work expands our knowledge of the Toxoplasma Golgi apparatus and identifies potential targets for therapeutic intervention.

Keywords:  ER exit sites; Golgi apparatus; Toxoplasma gondii; apicomplexan parasites; protein trafficking; secretory pathway; vesicular trafficking

DOI:  https://doi.org/10.1128/mbio.02380-24
PLoS Pathog. 2024 Sep 30. 20(9): e1012593

ATM1, an essential conserved transporter in Apicomplexa, bridges mitochondrial and cytosolic [Fe-S] biogenesis.

Deepti Shrivastava, Ernest Abboud, Jadhav Prasad Ramchandra, Akanksha Jha, Jean-Baptiste Marq, Animesh Chaurasia, Kalyan Mitra, Mohammad Sadik, Mohammad Imran Siddiqi, Dominique Soldati-Favre, Joachim Kloehn, Saman Habib.

The Apicomplexa phylum encompasses numerous obligate intracellular parasites, some associated with severe implications for human health, including Plasmodium, Cryptosporidium, and Toxoplasma gondii. The iron-sulfur cluster [Fe-S] biogenesis ISC pathway, localized within the mitochondrion or mitosome of these parasites, is vital for parasite survival and development. Previous work on T. gondii and Plasmodium falciparum provided insights into the mechanisms of [Fe-S] biogenesis within this phylum, while the transporter linking mitochondria-generated [Fe-S] with the cytosolic [Fe-S] assembly (CIA) pathway remained elusive. This critical step is catalyzed by a well-conserved ABC transporter, termed ATM1 in yeast, ATM3 in plants and ABCB7 in mammals. Here, we identify and characterize this transporter in two clinically relevant Apicomplexa. We demonstrate that depletion of TgATM1 does not specifically impair mitochondrial metabolism. Instead, proteomic analyses reveal that TgATM1 expression levels inversely correlate with the abundance of proteins that participate in the transfer of [Fe-S] to cytosolic proteins at the outer mitochondrial membrane. Further insights into the role of TgATM1 are gained through functional complementation with the well-characterized yeast homolog. Biochemical characterization of PfATM1 confirms its role as a functional ABC transporter, modulated by oxidized glutathione (GSSG) and [4Fe-4S].

DOI: https://doi.org/10.1371/journal.ppat.1012593
bioRxiv. 2024 Sep 18. pii: 2024.09.17.613578. [Epub ahead of print]

Cap-independent translation directs stress-induced differentiation of the protozoan parasite Toxoplasma gondii.

Vishakha Dey, Michael J Holmes, Matheus S Bastos, Ronald C Wek, William J Sullivan.

Translational control mechanisms modulate microbial latency of eukaryotic pathogens, enabling them to evade immunity and drug treatments. The protozoan parasite Toxoplasma gondii persists in hosts by differentiating from proliferative tachyzoites to latent bradyzoites, which are housed inside tissue cysts. Transcriptional changes facilitating bradyzoite conversion are mediated by a Myb domain transcription factor called BFD1, whose mRNA is present in tachyzoites but not translated into protein until stress is applied to induce differentiation. We addressed the mechanisms by which translational control drives BFD1 synthesis in response to stress-induced parasite differentiation. Using biochemical and molecular approaches, we show that the 5'-leader of BFD1 mRNA is sufficient for preferential translation upon stress. The translational control of BFD1 mRNA is maintained when ribosome assembly near its 5'-cap is impaired by insertion of a 5'-proximal stem-loop and upon knockdown of the Toxoplasma cap-binding protein, eIF4E1. Moreover, we show that a trans -acting RNA-binding protein called BFD2/ROCY1 is necessary for cap-independent translation of BFD1 through its binding to the 5'-leader. Translation of BFD2 mRNA is also suggested to be preferentially induced under stress, but by a cap-dependent mechanism. These results show that translational control and differentiation in Toxoplasma proceed through cap-independent mechanisms in addition to canonical cap-dependent translation. Our identification of cap-independent translation in protozoa underscores the antiquity of this mode of gene regulation in cellular evolution and its central role in stress-induced life-cycle events.

DOI: https://doi.org/10.1101/2024.09.17.613578
Essays Biochem. 2024 Oct 03. 68(2): 53-55

Uncovering malate dehydrogenase: structure, function and role in disease.

Celeste N Peterson, Kathleen Cornely, Amy D Parente, Amy L Springer, Joseph J Provost.

  Malate dehydrogenases (MDHs) have been extensively studied since the 1960s due to their key roles in carbon metabolism and pathways such as redox balance and lipid synthesis. Recently, there has been renewed interest in these enzymes with the discovery of their role in the metabolic changes that occur during cancer and a widespread community of undergraduate teaching laboratories addressing MDH research questions, the Malate Dehydrogenase CUREs Community (MCC). This special issue describes different facets of MDH, including its physiological role, its structure-function relationships, its regulation through post-translational modifications, and perspectives on its evolutionary history. There are two human isoforms: a cytoplasmic isoform that carries out formation of NAD+ for glycolysis, and a mitochondrial isoform that plays a major role in the citric acid cycle. Although the sequences of these two isoforms vary, the structures of the enzymes are similar, and studies suggest that each isoform may form complexes with other enzymes in common pathways. Experimental and theoretical advances have helped to characterize the post-translational modifications of MDH, allowing us to ask more complex questions involving the regulation of the enzyme and substrate promiscuity in the context of cancer. Additionally, there are many unresolved questions on the role of malate dehydrogenase in other organisms, especially in parasites. The review articles in this issue seek to shed light on the latest advances in our understanding of MDH and highlight areas for future studies.

Keywords:  CUREs; Cancer; Evolution; Metabolism; Regulation; Structure

DOI:  https://doi.org/10.1042/EBC20240044
Infect Disord Drug Targets. 2024 Sep 30.

Structural Prediction and Antigenic Analysis of ROP18, MIC4, and SAG1 Proteins to Improve Vaccine Design against Toxoplasma gondii: An In silico Approach.

Tooran Nayeri, Shahabeddin Sarvi, Mahdi Fasihi-Ramandi, Hossein Asgarian-Omran, Abolghasem Ajami, Zahra Hosseininejad, Samira Dodangeh, Ahmad Daryani.

   BACKGROUND: Toxoplasmosis is a cosmopolitan infectious disease in warm-blooded mammals that poses a serious worldwide threat due to the lack of effective medications and vaccines.
AIMS: The purpose of this study was to design a multi-epitope vaccine using several bioinfor-matics approaches against the antigens of Toxoplasma gondii (T. gondii).
METHODS: Three proteins of T. gondii, including ROP18, MIC4, and SAG1, were analyzed to predict the most dominant B- and T-cell epitopes. Finally, we designed a chimeric immunogen RMS (ROP18, MIC4, and SAG1) using some domains of ROP18 (N377-E546), MIC4 (D302-G471), and SAG1 (T130-L299) linked by rigid linker A (EAAAK) A. Physicochemical prop-erties, secondary and tertiary structures, antigenicity, and allergenicity of RMS were predicted utilizing immunoinformatic tools and servers.
RESULTS: RMS protein had 545 amino acids with a molecular weight (MW) of 58,833.46 Da and a theoretical isoelectric point (IP) of 6.47. The secondary structure of RMS protein con-tained 21.28% alpha-helix, 24.59% extended strand, and 54.13% random coil. In addition, eval-uation of antigenicity and allergenicity showed the protein to be an immunogen and non-aller-gen. The results of the Ramachandran plot indicated that 76.4%, 12.9%, and 10.7% of amino acid residues were incorporated in the favored, allowed, and outlier regions, respectively. ΔG of the best-predicted mRNA secondary structure was -593.80 kcal/mol, which indicated that a stable loop was not formed at the 5' end.
CONCLUSION: Finally, the accuracy and precision of the in silico analysis must be confirmed by successful heterologous expression and experimental studies.

Keywords:  MIC4; ROP18; SAG1; Toxoplasma gondii; in silico; vaccine.

DOI:  https://doi.org/10.2174/0118715265332103240911113422
Arch Pharm (Weinheim). 2024 Sep 28. e2400661

Symmetrical 2,7-disubstituted 9H-fluoren-9-one as a novel and promising scaffold for selective targeting of SIRT2.

Selen Gozde Kaya, Gokcen Eren, Alberto Massarotti, Habibe Beyza Gunindi, Filiz Bakar-Ates, Erva Ozkan.

  Sirtuin 2 (SIRT2) belongs to the family of silent information regulators (sirtuins), which comprises nicotinamide adenine dinucleotide (NAD+)-dependent protein lysine deacetylases. With a distribution across numerous tissues and organs of the human body, SIRT2 is involved in a wide range of physiological and pathological processes, such as regulating the cell cycle, energy metabolism, DNA repair, and tumorigenesis. Aberrant expression of SIRT2 has been closely associated with particular etiologies of human diseases, positioning SIRT2 as a promising therapeutic target. Herein, we detail the design overview and findings of novel symmetrical 2,7-disubstituted 9H-fluoren-9-one derivatives targeting SIRT2. SG3 displayed the most potent SIRT2-selective inhibitory profile, with an IC50 value of 1.95 μM$\mu {\rm{M}}$ , and reduced the cell viability of human breast cancer MCF-7 cells accompanied by hyperacetylation of α-tubulin. Finally, molecular docking, molecular dynamics simulations, and binding free energy calculations using molecular mechanics/generalized born surface area method were performed to verify the binding ability of SG3 to SIRT2. Taken together, these results could enhance our understanding of the structural elements necessary for inhibiting SIRT2 and shed light on the mechanism of inhibition.

Keywords:  CADD; SIRT2; fluorenone; sirtuin; α‐tubulin

DOI:  https://doi.org/10.1002/ardp.202400661
Biomedicines. 2024 Aug 23. pii: 1942. [Epub ahead of print]12(9):

Renal Fibrosis: SIRT1 Still of Value.

Huailiang Wu, Zhen Qiu, Liyan Wang, Wei Li.

  Chronic kidney disease (CKD) is a major global health concern. Renal fibrosis, a prevalent outcome regardless of the initial cause, ultimately leads to end-stage renal disease. Glomerulosclerosis and renal interstitial fibrosis are the primary pathological features. Preventing and slowing renal fibrosis are considered effective strategies for delaying CKD progression. However, effective treatments are lacking. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase belonging to class III histone deacetylases, is implicated in the physiological regulation and protection of the kidney and is susceptible to a diverse array of pathological influences, as demonstrated in previous studies. Interestingly, controversial conclusions have emerged as research has progressed. This review provides a comprehensive summary of the current understanding and advancements in the field; specifically, the biological roles and mechanisms of SIRT1 in regulating renal fibrosis progression. These include aspects such as lipid metabolism, epithelial-mesenchymal transition, oxidative stress, aging, inflammation, and autophagy. This manuscript explores the potential of SIRT1 as a therapeutic target for renal fibrosis and offers new perspectives on treatment approaches and prognostic assessments.

Keywords:  SIRT1; aging; lipid metabolism; oxidative stress; renal fibrosis

DOI:  https://doi.org/10.3390/biomedicines12091942
iScience. 2024 Oct 18. 27(10): 110911

Sirtuin 1/sirtuin 3 are robust lysine delactylases and sirtuin 1-mediated delactylation regulates glycolysis.

Runhua Du, Yanmei Gao, Cong Yan, Xuelian Ren, Shankang Qi, Guobin Liu, Xinlong Guo, Xiaohan Song, Hanmin Wang, Jingxin Rao, Yi Zang, Mingyue Zheng, Jia Li, He Huang.

  Lysine lactylation (Kla), an epigenetic mark triggered by lactate during glycolysis, including the Warburg effect, bridges metabolism and gene regulation. Enzymes such as p300 and HDAC1/3 have been pivotal in deciphering the regulatory dynamics of Kla, though questions about additional regulatory enzymes, their specific Kla substrates, and the underlying functional mechanisms persist. Here, we identify SIRT1 and SIRT3 as key "erasers" of Kla, shedding light on their selective regulation of both histone and non-histone proteins. Proteomic analysis in SIRT1/SIRT3 knockout HepG2 cells reveals distinct substrate specificities toward Kla, highlighting their unique roles in cellular signaling. Notably, we highlight the role of specific Kla modifications, such as those on the M2 splice isoform of pyruvate kinase (PKM2), in modulating metabolic pathways and cell proliferation, thereby expanding Kla's recognized functions beyond epigenetics. Therefore, this study deepens our understanding of Kla's functional mechanisms and broadens its biological significance.

Keywords:  Biological sciences; Molecular biology; Molecular interaction

DOI:  https://doi.org/10.1016/j.isci.2024.110911
Gut Pathog. 2024 Sep 29. 16(1): 53

Toxoplasma Gondii in humans, animals and in the environment in Morocco: a literature review.

Ilham Atif, Oulaid Touloun, Samia Boussaa.

  Toxoplasmosis, caused by Toxoplasma gondii, has the unsettling ability to infect nearly every warm-blooded vertebrate. When transmitted from mother to fetus during pregnancy, it can lead to congenital toxoplasmosis in newborns, which may have severe and even fatal outcomes. Moreover, this parasite is a significant cause of reproductive issues in cattle. The aim of this literature review was to compile and synthesize information on the epidemiology and clinical features of naturally occurring Toxoplasma gondii infections in both humans and animals, as well as to assess the occurrence of oocysts in the environmental matrices in Morocco. To achieve these objectives, data were sourced from four electronic databases: PubMed, Web of Science, Scopus, and Google Scholar. A total of 32 articles published between January 1, 2000, and January 31, 2024, met the inclusion criteria. The findings indicated that the seroprevalence of T. gondii among pregnant women varied by city and appeared to be lower in drier climates. The study identified several risk factors associated with T. gondii infection among women in Morocco, including direct contact with soil, failure to wash fruits and vegetables before eating, limited education, and reliance on well water for drinking. Moreover, there is a limited amount of serological data on T. gondii in animals. In Morocco, the prevalence of this parasite can reach up to 30% in sheep, while it stands at 8.5% in cattle and goats. Leafy greens are particularly prone to hosting pathogens and are associated with foodborne outbreaks. In Morocco, the prevalence of T. gondii in leafy vegetables is around 16%, although soil analyses have not found any oocysts. This review offers a thorough epidemiological overview of T. gondii infections in Morocco, serving as a valuable resource for researchers and aiding in the development of control and prevention programs.

Keywords:   Toxoplasma Gondi ; Animals; Environment; Humans; Morocco

DOI:  https://doi.org/10.1186/s13099-024-00645-5
Int J Biol Macromol. 2024 Oct 02. pii: S0141-8130(24)07008-9. [Epub ahead of print] 136199

The new function of FaSRT2-1 protein in energy metabolism: Promoting strawberry fruit quality and ripening.

Min Yang, Chenghui Song, Xinrong He, Liangxin Wang, Caixia He, Hong Yu, Wenfei Xiao, Yuanxiu Lin, Yunting Zhang, Yan Wang, Wen He, Qing Chen, Yong Zhang, Xiaorong Wang, Haoru Tang, Mengyao Li, Ya Luo.

  Sirtuins (SRTs) are nicotinamide adenine dinucleotide (NAD+) dependent II histone deacetylases (HDACs) that have been understudied in horticultural crops. However, their functions in regulating mitochondrial energy metabolism and influencing fruit development and quality formation remain unclear. In this study, we found that FaSRT2-1 exhibits diverse subcellular localizations. Overexpression of FaSRT2-1 promoted strawberry fruit quality formation (soluble sugars, organic acids, anthocyanins) and accelerated ripening. Conversely, knockout of FaSRT2-1 yielded opposite results. During fruit ripening, ATP content and ATP/ADP ratio gradually increased, and FaSRT2-1 promoted ATP accumulation and decreased before and after the deep red stage, respectively, indicating its role in fruit ripening and senescence. FaSRT2-1 interacted with energy-related proteins (FaRPT4a, FaATPβ and FaATPγ) to increase ATP content and the ATP/ADP ratio. Additionally, FaSRT2-1 collaborated with FaGDH2 and FaWDR5B to increase the accumulation of soluble sugars, organic acids and anthocyanins. Meanwhile, FaRPT4a, FaATPγ, FaGDH2 and FaWDR5B were co-localized with FaSRT2-1, while FaATPβ was localized in both the cytoplasm and mitochondria. Transient overexpression experiments further highlight the roles of FaRPT4a and FaGDH2/FaWDR5B in modulating ATP accumulation and fruit ripening, respectively. In summary, FaSRT2-1 plays important roles in promoting strawberry fruit ripening, senescence and quality formation by regulating energy metabolism.

Keywords:  Energy metabolism; Sirtuin protein; Strawberry fruit ripening

DOI:  https://doi.org/10.1016/j.ijbiomac.2024.136199
Metabolism. 2024 Oct 01. pii: S0026-0495(24)00269-5. [Epub ahead of print] 156041

Inhibition of ACSS2 triggers glycolysis inhibition and nuclear translocation to activate SIRT1/ATG5/ATG2B deacetylation axis, promoting autophagy and reducing malignancy and chemoresistance in ovarian cancer.

Jiang Yang, Haoyu Wang, Bingshu Li, Jingchun Liu, Xiaoyi Zhang, Ying Wang, Jiaxin Peng, Likun Gao, Xinqi Wang, Siyuan Hu, Wenyi Zhang, Li Hong.

   BACKGROUND: Metabolic reprogramming is a hallmark of cancer, characterized by a high dependence on glycolysis and an enhanced utilization of acetate as an alternative carbon source. ACSS2 is a critical regulator of acetate metabolism, playing a significant role in the development and progression of various malignancies. ACSS2 facilitates the conversion of acetate to acetyl-CoA, which participates in multiple metabolic pathways and functions as an epigenetic regulator of protein acetylation, thereby modulating key cellular processes such as autophagy. However, the roles and intrinsic connections of ACSS2, glycolysis, protein acetylation, and autophagy in ovarian cancer (OC) remain to be elucidated.
BASIC PROCEDURES: Utilizing clinical specimens and online databases, we analysed the expression of ACSS2 in OC and its relationship with clinical prognosis. By knocking down ACSS2, we evaluated its effects on the malignant phenotype, acetate metabolism, glycolysis, and autophagy. The metabolic alterations in OC cells were comprehensively analysed using Seahorse assays, transmission electron microscopy, membrane potential measurements, and stable-isotope labeling techniques. CUT&TAG and co-immunoprecipitation techniques were employed to explore the deacetylation of autophagy-related proteins mediated by ACSS2 via SIRT1. Additionally, through molecular docking, transcriptome sequencing, and metabolomics analyses, we validated the pharmacological effects of paeonol on ACSS2 and the glycolytic process in OC cells. Finally, both in vitro and in vivo experiments were performed to investigate the impact of paeonol on autophagy and its anti-OC effects mediated through the ACSS2/SIRT1 deacetylation axis.
MAIN FINDINGS: ACSS2 is significantly upregulated in OC and is associated with poor prognosis. Knockdown of ACSS2 inhibits OC cells proliferation, migration, invasion, angiogenesis, and platinum resistance, while reducing tumour burden in vivo. Mechanistically, inhibiting ACSS2 reduces acetate metabolism and suppresses glycolysis by targeting HXK2. This glycolytic reduction promotes the translocation of ACSS2 from the cytoplasm to the nucleus, leading to increased expression of the deacetylase SIRT1. SIRT1 mediates the deacetylation of autophagy-related proteins, such as ATG5 and ATG2B, thereby significantly activating autophagy in OC cells and exerting antitumor effects. Paeonol inhibits acetate metabolism and glycolysis in OC cells by targeting ACSS2. Paeonol activates autophagy through the ACSS2/SIRT1/ATG5/ATG2B deacetylation axis, demonstrating inhibition of OC in vitro and in vivo.
PRINCIPAL CONCLUSIONS: Pae can serve as an effective, low-toxicity, multi-targeted drug targeting ACSS2 and glycolysis. It activates autophagy through the ACSS2/SIRT1/ATG5/ATG2B deacetylation signalling cascade, thereby exerting anti-OC effects. Our study provides new insights into the malignant mechanisms of OC and offers a novel strategy for its treatment.

Keywords:  ACSS2; Autophagy; Glycolysis; Ovarian cancer; Paeonol; SIRT1

DOI:  https://doi.org/10.1016/j.metabol.2024.156041
PLoS Negl Trop Dis. 2024 Oct 03. 18(10): e0012569

Involvement of INS15 in the development and pathogenicity of the zoonotic pathogen Cryptosporidium parvum.

Wei He, Hao Cui, Na Li, Yaqiong Guo, Songrong Zeng, Yaoyu Feng, Lihua Xiao, Rui Xu.

BACKGROUND: Cryptosporidium parvum is a common protozoan pathogen responsible for moderate to severe diarrhea in humans and animals. The C. parvum genome contains 22 genes encoding insulinase-like M16 proteases (INS) with diverse structures and sequences, suggesting that members of the protein family may have distinct biological functions in the life cycle of parasites. Here, we investigated the role of INS15 and INS16, two proteases encoded by neighboring genes with high sequence identity, in the growth and development of C. parvum in vivo and in vitro.
METHODOLOGY/PRINCIPAL FINDINGS: INS15 and INS16 genes were tagged and knocked out using CRISPR/Cas9 technology in C. parvum IIdA20G1-HLJ isolate. The expression of INS15 and INS16 was determined by immunofluorescence analysis and immunoelectron microscopy. The effect of depletion of INS15 and INS16 on parasite growth and pathogenicity were assessed on HCT-8 cells and in interferon-γ knockout mice. Endogenous tagging showed that INS15 and INS16 expressed in the oocyst, trophozoite, meront and female gametes. INS15 also expressed in male gamonts, while INS16 was not detected in the male gamonts. Although depletion of the INS15 or INS16 gene affected late development of C. parvum in vitro, only depletion of INS15 significantly reduced parasite burden in infected mice. Mice infected with the INS15-depleted strain had reduced clinical signs, body weight, intestinal villus length to crypt height ratio, and survival time compared to infected with the tagging mutant.
CONCLUSIONS/SIGNIFICANCE: The results of this study indicate that INS15 is mainly involved in the late development of C. parvum. Depletion of this gene attenuates the pathogenicity of this important zoonotic parasite.

DOI: https://doi.org/10.1371/journal.pntd.0012569
Drug Target Insights. 2024 Jan-Dec;18:18 70-77

Enhancement of apoptosis in Caco-2, Hep-G2, and HT29 cancer cell lines following exposure to Toxoplasma gondii peptides.

Firooz Shahrivar, Javid Sadraei, Majid Pirestani, Ehsan Ahmadpour.

   Objective: Cancer or neoplasm is a cosmopolitan catastrophe that results in more than 20 million new cases and 10 million deaths every year. Some factors lead to carcinogenesis like infectious diseases. Parasites like Toxoplasma gondii, by its components, could modulate the cancer system by inducing apoptosis. The objective of this investigation is to assess the potential of peptides derived from T. gondii in combating cancer by examining their effects on Caco-2, Hep-G2, and HT29 cell lines.
Materials and methods: Candidate peptide by its similarity to anticancer compounds was predicted through the computer-based analysis/platform. The impact of the peptide on cell viability, cell proliferation, and gene expression was evaluated through the utilization of MTT assay, flow cytometry, and real-time polymerase chain reaction (PCR) methodologies.
Results: The cell viability rate exhibited a significant decrease (p < 0.001) across all cell lines when exposed to a concentration of ≤160 μg. Within the 48-hour timeframe, the half maximal inhibitory concentration (IC50) for HT29 and Hep-G2 cell lines was determined to be 107.2 and 140.6 μg/mL, respectively. Notably, a marked decrease in the expression levels of Bcl2 and APAF1 genes was observed in both the Hep-G2 and HT29 cell lines.
Conclusion: These findings indicate that the T. gondii peptide affected cancer cell mortality and led to changes in the expression of genes associated with apoptosis.

Keywords:  Anticancer; Neoplasm; Parasite; Peptides; Real-time PCR; Toxoplasmosis

DOI:  https://doi.org/10.33393/dti.2024.3177
Mol Metab. 2024 Oct 01. pii: S2212-8778(24)00173-X. [Epub ahead of print] 102042

The metabolic sensor AMPK: Twelve enzymes in one.

William J Smiles, Ashley J Ovens, Jonathan S Oakhill, Barbara Kofler.

   BACKGROUND: AMP-activated protein kinase (AMPK) is an evolutionarily conserved regulator of energy metabolism. AMPK is sensitive to acute perturbations to cellular energy status and leverages fundamental bioenergetic pathways to maintain cellular homeostasis. AMPK is a heterotrimer comprised of αβγ-subunits that in humans are encoded by seven individual genes (isoforms α1, α2, β1, β2, γ1, γ2 and γ3), permitting formation of at least 12 different complexes with personalised biochemical fingerprints and tissue expression patterns. While the canonical activation mechanisms of AMPK are well-defined, delineation of subtle, as well as substantial, differences in the regulation of heterogenous AMPK complexes remain poorly defined.
SCOPE OF REVIEW: Here, taking advantage of multidisciplinary findings, we dissect the many aspects of isoform-specific AMPK function and links to health and disease. These include, but are not limited to, allosteric activation by adenine nucleotides and small molecules, co-translational myristoylation and post-translational modifications (particularly phosphorylation), governance of subcellular localisation, and control of transcriptional networks. Finally, we delve into current debate over whether AMPK can form novel protein complexes (e.g., dimers lacking the α-subunit), altogether highlighting opportunities for future and impactful research.
MAJOR CONCLUSIONS: Baseline activity of α1-AMPK is higher than its α2 counterpart and is more sensitive to synergistic allosteric activation by metabolites and small molecules. α2 complexes however show a greater response to energy stress (i.e., AMP production) and appear to be better substrates for LKB1 and mTORC1 upstream. These differences may explain to some extent why in certain cancers α1 is a tumour promoter and α2 a suppressor. β1-AMPK activity is toggled by a 'myristoyl-switch' mechanism that likely precedes a series of signalling events culminating in phosphorylation by ULK1 and sensitisation to small molecules or endogenous ligands like fatty acids. β2-AMPK, not entirely beholden to this myristoyl-switch, has a greater propensity to infiltrate the nucleus, which we suspect contributes to its oncogenicity in some cancers. Last, the unique N-terminal extensions of the γ2 and γ3 isoforms are major regulatory domains of AMPK. mTORC1 may directly phosphorylate this region in γ2, although whether this is inhibitory, especially in disease states, is unclear. Conversely, γ3 complexes might be preferentially targeted by mTORC1 in response to physical exercise.

Keywords:  AMPK; cancer; exercise; mTORC1; metabolism; signalling

DOI:  https://doi.org/10.1016/j.molmet.2024.102042
Biomolecules. 2024 Sep 15. pii: 1160. [Epub ahead of print]14(9):

Sirt2 Regulates Liver Metabolism in a Sex-Specific Manner.

Alexandra V Schmidt, Sivakama S Bharathi, Keaton J Solo, Joanna Bons, Jacob P Rose, Birgit Schilling, Eric S Goetzman.

  Sirtuin-2 (Sirt2), an NAD+-dependent lysine deacylase enzyme, has previously been implicated as a regulator of glucose metabolism, but the specific mechanisms remain poorly defined. Here, we observed that Sirt2-/- males, but not females, have decreased body fat, moderate hypoglycemia upon fasting, and perturbed glucose handling during exercise compared to wild type controls. Conversion of injected lactate, pyruvate, and glycerol boluses into glucose via gluconeogenesis was impaired, but only in males. Primary Sirt2-/- male hepatocytes exhibited reduced glycolysis and reduced mitochondrial respiration. RNAseq and proteomics were used to interrogate the mechanisms behind this liver phenotype. Loss of Sirt2 did not lead to transcriptional dysregulation, as very few genes were altered in the transcriptome. In keeping with this, there were also negligible changes to protein abundance. Site-specific quantification of the hepatic acetylome, however, showed that 13% of all detected acetylated peptides were significantly increased in Sirt2-/- male liver versus wild type, representing putative Sirt2 target sites. Strikingly, none of these putative target sites were hyperacetylated in Sirt2-/- female liver. The target sites in the male liver were distributed across mitochondria (44%), cytoplasm (32%), nucleus (8%), and other compartments (16%). Despite the high number of putative mitochondrial Sirt2 targets, Sirt2 antigen was not detected in purified wild type liver mitochondria, suggesting that Sirt2's regulation of mitochondrial function occurs from outside the organelle. We conclude that Sirt2 regulates hepatic protein acetylation and metabolism in a sex-specific manner.

Keywords:  gluconeogenesis; glucose; liver; metabolism; sirt-2; sirtuin

DOI:  https://doi.org/10.3390/biom14091160
Gene. 2024 Oct 01. pii: S0378-1119(24)00857-6. [Epub ahead of print] 148976

NIPSNAP3A regulates cellular homeostasis by modulating mitochondrial dynamics.

Run Yan, Liting Chen, Zimu Cai, Jiyao Tang, Yanlin Zhu, Yanping Li, Xuemin Wang, Yu Ruan, Qi Han.

  Mitochondria are essential for cell metabolism and survival as they produce the majority of cellular ATP through oxidative phosphorylation as well as regulate critical processes such as cell proliferation and apoptosis. NIPSNAP family of proteins are predominantly mitochondrial matrix proteins. However, the molecular and cellular functions of the NIPSNAPs, particularly NIPSNAP3A, have remained elusive. Here, we demonstrated that NIPSNAP3A knockdown in HeLa cells inhibited their proliferation and migration and attenuated apoptosis induced by Actinomycin D (Act-D). These findings suggested a complex relationship between cellular processes and mitochondrial functions, mediated by NIPSNAP3A. Further investigations revealed that NIPSNAP3A knockdown not only inhibited mitochondrial fission through reduction of DRP1-S616, but also suppressed cytochrome c release in apoptosis. Collectively, our findings highlight the critical role of NIPSNAP3A in coordinating cellular processes, likely through its influence on mitochondrial dynamics.

Keywords:  Apoptosis; Drp1; Fission; Mitochodnria; NIPSNAP3A; Proliferation

DOI:  https://doi.org/10.1016/j.gene.2024.148976
Proc Natl Acad Sci U S A. 2024 Oct 08. 121(41): e2410995121

Capturing a methanogenic carbon monoxide dehydrogenase/acetyl-CoA synthase complex via cryogenic electron microscopy.

Alison Biester, David A Grahame, Catherine L Drennan.

  Approximately two-thirds of the estimated one-billion metric tons of methane produced annually by methanogens is derived from the cleavage of acetate. Acetate is broken down by a Ni-Fe-S-containing A-cluster within the enzyme acetyl-CoA synthase (ACS) to carbon monoxide (CO) and a methyl group (CH3+). The methyl group ultimately forms the greenhouse gas methane, whereas CO is converted to the greenhouse gas carbon dioxide (CO2) by a Ni-Fe-S-containing C-cluster within the enzyme carbon monoxide dehydrogenase (CODH). Although structures have been solved of CODH/ACS from acetogens, which use these enzymes to make acetate from CO2, no structure of a CODH/ACS from a methanogen has been reported. In this work, we use cryo-electron microscopy to reveal the structure of a methanogenic CODH and CODH/ACS from Methanosarcina thermophila (MetCODH/ACS). We find that the N-terminal domain of acetogenic ACS, which is missing in all methanogens, is replaced by a domain of CODH. This CODH domain provides a channel for CO to travel between the two catalytic Ni-Fe-S clusters. It generates the binding surface for ACS and creates a remarkably similar CO alcove above the A-cluster using residues from CODH rather than ACS. Comparison of our MetCODH/ACS structure with our MetCODH structure reveals a molecular mechanism to restrict gas flow from the CO channel when ACS departs, preventing CO escape into the cell. Overall, these long-awaited structures of a methanogenic CODH/ACS reveal striking functional similarities to their acetogenic counterparts despite a substantial difference in domain organization.

Keywords:  cryogenic electron microscopy; gas channels; greenhouse gases; methanogenesis

DOI:  https://doi.org/10.1073/pnas.2410995121
Eur J Med Res. 2024 Oct 05. 29(1): 489

Parasites revive hope for cancer therapy.

Maha M Eissa, Ahmed Ebada Salem, Nahla El Skhawy.

  Parasites have attained a life-long stigma of being detrimental organisms with deleterious outcomes. Yet, recently, a creditable twist was verified that can dramatically change our perception of those parasites from being a source of misery to millions of people to a useful anti-cancerous tool. Various parasites have shown promise to combat cancer in different experimental models, including colorectal, lung, and breast cancers, among others. Helminths and protozoan parasites, as well as their derivatives such as Echinococcus granulosus protein KI-1, Toxoplasma gondii GRA15II, and Trypanosoma cruzi calreticulin, have demonstrated the ability to inhibit tumor growth, angiogenesis, and metastasis. This article provides an overview of the literature on various cancer types that have shown promising responses to parasite therapy in both in vitro and in vivo animal studies. Parasites have shown anti-neoplastic activity through a variety of mechanisms that collectively contribute to their anti-cancer properties. These include immunomodulation, inhibition of angiogenesis, and molecular mimicry with cancer cells. This review article sheds light on this intriguing emerging field and emphasizes the value of collaborative multidisciplinary research projects with funding agencies and pharmaceutical companies. Thus, these strategies would secure continuous exploration of this new avenue and accelerate the advancement of cancer therapy research. Although experimental studies are heavily conducted by leaps and bounds, further steps are definitely lagging. Upgrading research from the experimental level to the clinical trial would be a wise progression toward efficient exploitation of the anti-neoplastic capabilities of parasites, ultimately saving countless lives.

Keywords:  Anti-angiogenesis; Cancer immunotherapy; Cancer vaccine candidates; Immunomodulation; Molecular mimicry theory; Parasitic immunotherapy

DOI:  https://doi.org/10.1186/s40001-024-02057-2
bioRxiv. 2024 Sep 25. pii: 2024.09.15.613154. [Epub ahead of print]

Inositol Hexaphosphate (InsP6) Activates the HDAC1/3 Epigenetic Axis to Maintain Intestinal Barrier Function.

Sujan Chatterjee, Loretta Viera Preval, Zachary Sin, Nguyen Tran, Kevin Ritter, Xue Bessie Su, Jakob P Centlivre, Saharat Jolak Ragsac, Richard Van, Seungman Park, Mira Han, Qian Liu, Brian P Hedlund, Adolfo Saiardi, Henning Jessen, Prasun Guha.

HDACs (histone deacetylase) play a crucial role in regulating gene expression, and the inhibition of these enzymes is gaining attention as a promising therapeutic approach for cancer treatment. Despite their significant physiological and clinical importance, the mechanisms of HDAC activation remain poorly understood. This study reveals that inositol polyphosphate multikinase (IPMK) is essential for activating HDAC1 and HDAC3 in cell lines and mice. IPMK deletion or inactivation of its kinase activity selectively impairs HDAC1/3's deacetylase activity, significantly influencing gene expression. Disruption of the IPMK-HDAC1/3 epigenetic axis results in transcriptional upregulation of matrix metalloproteinase (MMP) genes, exacerbating cell and intestinal permeability. Remarkably, treatment of IPMK KO cells with cell-permeable inositol hexaphosphate (InsP6) rescues these defects. This study elucidates the role of IPMK's kinase activity in HDAC1/3 activation and its implications for intestinal barrier function.

DOI: https://doi.org/10.1101/2024.09.15.613154
J Med Chem. 2024 Oct 03.

Addressing the Intracellular Vestibule of the Plasmodial Lactate Transporter PfFNT by p-Substituted Inhibitors Amplifies In Vitro Activity.

Cornelius Nerlich, Finn Tiedjens, Robin Hertel, Björn Henke, Susan Häuer, Lea S Panitzsch, Kerrin Hansen, Ole Franck, Antonio Mete, Didier Leroy, Dennis Schade, Christian Peifer, Stefan Hannus, Frank Becker, Sergio Wittlin, Tobias Spielmann, Eric Beitz.

Inhibition of the lactate transporter PfFNT is a valid novel mode of action against malaria parasites. Current pyridine-substituted pentafluoro-3-hydroxy-pent-2-en-1-ones act as substrate analogs with submicromolar EC50 in vitro, and >99.7% activity in mice. The recently solved structure of a PfFNT-inhibitor complex visualized the binding mode. Here, we extended the inhibitor layout by series of amine- and anilide-linked pyridine p-substituents to generate additional interactions in the cytoplasmic vestibule. Virtual docking indicated hydrogen bonding to Tyr31 and Ser102. Fluorescence cross-correlation spectroscopy yielded respectively enhanced target affinity. Strikingly, the in vitro activity increased by 1 order of magnitude to 14.8 nM at negligible cytotoxicity. While p-amine substitutions were rapidly metabolized, the more stable p-acetanilide cleared 99.7% of parasites at 4 × 50 mg kg-1 in a mouse malaria model. Future stabilization of the p-substitution against metabolism may translate the gain in in vitro potency to the in vivo situation.

DOI: https://doi.org/10.1021/acs.jmedchem.4c01674
bioRxiv. 2024 Sep 22. pii: 2024.09.18.613658. [Epub ahead of print]

Quantitative analysis of non-histone lysine methylation sites and lysine demethylases in breast cancer cell lines.

Christine A Berryhill, Taylor N Evans, Emma H Doud, Whitney R Smith-Kinnaman, Jocelyne N Hanquier, Amber L Mosley, Evan M Cornett.

Growing evidence shows that lysine methylation is a widespread protein post-translational modification that regulates protein function on histone and non-histone proteins. Numerous studies have demonstrated that dysregulation of lysine methylation mediators contributes to cancer growth and chemotherapeutic resistance. While changes in histone methylation are well documented with extensive analytical techniques available, there is a lack of high-throughput methods to reproducibly quantify changes in the abundances of the mediators of lysine methylation and non-histone lysine methylation (Kme) simultaneously across multiple samples. Recent studies by our group and others have demonstrated that antibody enrichment is not required to detect lysine methylation, prompting us to investigate the use of Tandem Mass Tag (TMT) labeling for global Kme quantification sans antibody enrichment in four different breast cancer cell lines (MCF-7, MDA-MB-231, HCC1806, and MCF10A). To improve the quantification of KDMs, we incorporated a lysine demethylase (KDM) isobaric trigger channel, which enabled 96% of all KDMs to be quantified while simultaneously quantifying 326 Kme sites. Overall, 142 differentially abundant Kme sites and eight differentially abundant KDMs were identified between the four cell lines, revealing cell line-specific patterning.

DOI: https://doi.org/10.1101/2024.09.18.613658
Cell Chem Biol. 2024 Sep 26. pii: S2451-9456(24)00393-3. [Epub ahead of print]

Small molecules targeting selective PCK1 and PGC-1α lysine acetylation cause anti-diabetic action through increased lactate oxidation.

Beste Mutlu, Kfir Sharabi, Jee Hyung Sohn, Bo Yuan, Pedro Latorre-Muro, Xin Qin, Jin-Seon Yook, Hua Lin, Deyang Yu, João Paulo G Camporez, Shingo Kajimura, Gerald I Shulman, Sheng Hui, Theodore M Kamenecka, Patrick R Griffin, Pere Puigserver.

Small molecules selectively inducing peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1α acetylation and inhibiting glucagon-dependent gluconeogenesis causing anti-diabetic effects have been identified. However, how these small molecules selectively suppress the conversion of gluconeogenic metabolites into glucose without interfering with lipogenesis is unknown. Here, we show that a small molecule SR18292 inhibits hepatic glucose production by increasing lactate and glucose oxidation. SR18292 increases phosphoenolpyruvate carboxykinase 1 (PCK1) acetylation, which reverses its gluconeogenic reaction and favors oxaloacetate (OAA) synthesis from phosphoenolpyruvate. PCK1 reverse catalytic reaction induced by SR18292 supplies OAA to tricarboxylic acid (TCA) cycle and is required for increasing glucose and lactate oxidation and suppressing gluconeogenesis. Acetylation mimetic mutant PCK1 K91Q favors anaplerotic reaction and mimics the metabolic effects of SR18292 in hepatocytes. Liver-specific expression of PCK1 K91Q mutant ameliorates hyperglycemia in obese mice. Thus, SR18292 blocks gluconeogenesis by enhancing gluconeogenic substrate oxidation through PCK1 lysine acetylation, supporting the anti-diabetic effects of these small molecules.

DOI: https://doi.org/10.1016/j.chembiol.2024.09.001
J Cell Physiol. 2024 Oct 01. e31435

Research advances in protein lysine 2-hydroxyisobutyrylation: From mechanistic regulation to disease relevance.

Jinglei Huang, Hui Peng, Diqi Yang.

  Histone lysine 2-hydroxyisobutyrylation (Khib) was identified as a novel posttranslational modification in 2014. Significant progress has been made in understanding its roles in reproduction, development, and disease. Although 2-hydroxyisobutyrylation shares some overlapping modification sites and regulatory factors with other lysine residue modifications, its unique structure suggests distinct functions. This review summarizes the latest advancements in Khib, including its regulatory mechanisms, roles in mammalian physiological processes, and its relationship with diseases. This provides direction for further research on Khib and offers new perspectives for developing treatment strategies for related diseases.

Keywords:  2‐hydroxyisobutyrylation; PTM; cancer; development; disease; regulation

DOI:  https://doi.org/10.1002/jcp.31435
Am J Physiol Cell Physiol. 2024 Sep 30.

Asparagine as a Signal for Glutamine Sufficiency via Asparagine Synthetase: A Fresh Evidence-Based Framework in Physiology and Oncology.

Babatunde Olawuni, Barrie P Bode.

  Among the twenty proteinogenic amino acids, glutamine and asparagine represent a unique cohort in containing a terminal amide in their side chain, and share a direct metabolic relationship, with glutamine generating asparagine through the ATP-dependent asparagine synthetase (ASNS) reaction. Circulating glutamine levels and metabolic flux through cells and tissues greatly exceed those for asparagine, and "glutamine addiction" in cancer has likewise received considerable attention. However, historic and recent evidence collectively suggest that in spite of its modest presence, asparagine plays an outsized regulatory role in cellular function. Here, we present a unifying evidence-based hypothesis that the amides constitute a regulatory signaling circuit, with glutamine as a driver and asparagine as a second messenger that allosterically regulates key biochemical and physiological functions, particularly cell growth and survival. Specifically, it is proposed that ASNS serves as a sensor of substrate sufficiency for S-phase entry and progression in proliferating cells. ASNS-generated asparagine serves as a subsequent second messenger that modulates the activity of key regulatory proteins and promotes survival in the face of cellular stress, and serves as a feed-forward driver of S-phase progression in cell growth. We propose that this signaling pathway be termed the Amide Signaling Circuit (ASC) in homage to the SLC1A5-encoded ASCT2 that transports both glutamine and asparagine in a bidirectional manner, and has been implicated in the pathogenesis of a broad spectrum of human cancers. Support for the ASC model is provided by the recent discovery that glutamine is sensed in primary cilia via ASNS during metabolic stress.

Keywords:  Asparagine; Cancer; Glutamine; Metabolism; Signaling

DOI:  https://doi.org/10.1152/ajpcell.00316.2024
Commun Biol. 2024 Oct 04. 7(1): 1257

Selective inhibition of HDAC class IIA as therapeutic intervention for KMT2A-rearranged acute lymphoblastic leukemia.

Tamara C A I Verbeek, Kirsten S Vrenken, Susan T C J M Arentsen-Peters, Patricia Garrido Castro, Marieke van de Ven, Olaf van Tellingen, Rob Pieters, Ronald W Stam.

KMT2A-rearranged acute lymphoblastic leukemia (ALL) is characterized by deregulation of the epigenome and shows susceptibility towards histone deacetylase (HDAC) inhibition. Most broad-spectrum HDAC inhibitors simultaneously target multiple human HDAC isoforms. Consequently, they often induce toxicity and especially in combination with other therapeutic agents. Therefore, more specifically targeting HDAC isoforms may represent a safer therapeutic strategy. Here we show that shRNA-mediated knock-down of the class IIA HDAC isoforms HDAC4, HDAC5, and HDAC7 results in apoptosis induction and cell cycle arrest in KMT2A-rearranged ALL cells. In concordance, the HDAC4/5 selective small molecule inhibitor LMK-235 effectively eradicates KMT2A-rearranged ALL cell lines as well as primary patient samples in vitro. However, using a xenograft mouse model of KMT2A-rearranged ALL we found that the maximum achievable dose of LMK-235 was insufficient to induce anti-leukemic effects in vivo. Similar results were obtained for the specific class IIA HDAC inhibitors MC1568 and TMP195. Finally, LMK-235 appeared to exert minimal anti-leukemic effects in vivo in combination with the BCL-2 inhibitor venetoclax, but not enough to prolong survival in treated mice. In conclusion, class IIA HDAC isoforms represent attractive therapeutic target in KMT2A-rearranged ALL, although clinical applications require the development of more stable and efficient specific HDAC inhibitors.

DOI: https://doi.org/10.1038/s42003-024-06916-w