bims-midhyp 2023-10-08 papers

bims-midhyp

Biomed News

on Mitochondrial dysfunction and hypoxia

Issue of 2023–10–08
twenty-six papers selected by
Alia Ablieh, Universität Heidelberg

Metabolomics and mitochondrial dysfunction in cardiometabolic disease.
Mechanisms and regulation of human mitochondrial transcription.
p53 contributes to cardiovascular diseases via mitochondria dysfunction: A new paradigm.
Evaluation of Glycolysis and Mitochondrial Function in Endothelial Cells Using the Seahorse Analyzer.
NADH elevation during chronic hypoxia leads to VHL-mediated HIF-1α degradation via SIRT1 inhibition.
Pulmonary arterial hypertension drugs can partially restore altered angiogenic capacities in bmpr2-silenced human lung microvascular endothelial cells.
The glyoxylate shunt protein ICL-1 protects from mitochondrial superoxide stress through activation of the mitochondrial unfolded protein response.
Alteration of endothelial permeability ensures cardiomyocyte survival from ischemic insult in the subendocardium of the heart.
Mitochondrial dysfunction: A fatal blow in depression.
Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review.
Mechanisms controlling cellular and systemic iron homeostasis.
The Mineralocorticoid Receptor in the Vasculature: Friend or Foe?
A Multi-omic and Multi-Species Analysis of Right Ventricular Dysfunction.
An Unbiased Screen Identified the Hsp70-BAG3 Complex as a Regulator of Myosin-Binding Protein C3.
Determination of Tight Junction Integrity in Brain Endothelial Cells Based on Tight Junction Protein Expression.
The decoy oligodeoxynucleotide against HIF-1α and STAT5 ameliorates atopic dermatitis-like mouse model.
Novel regulators of islet function identified from genetic variation in mouse islet Ca2+ oscillations.
Multi-omics analysis revealed the mitochondrial-targeted drug combination to suppress the development of lung cancer.
Maturation of small nucleolar RNAs: from production to function.
Hypoxia-Induced miR-101 Impairs Endothelial Barrier Integrity Through Altering VE-Cadherin and Claudin-5.
Long noncoding RNAs as versatile molecular regulators of cellular stress response and homeostasis.
Plasma metabonomic study on the effect of Para‑hydroxybenzaldehyde intervention in a rat model of transient focal cerebral ischemia.
Control of Cell Death in Health and Disease.
Pgam5-mediated PHB2 dephosphorylation contributes to endotoxemia-induced myocardial dysfunction by inhibiting mitophagy and the mitochondrial unfolded protein response.
CCR5 drives NK cell-associated airway damage in pulmonary ischemia-reperfusion injury.
Characterizing genetic variation in the regulation of the ER stress response through computational and cis-eQTL analyses.

Life Sci. 2023 Oct 01. pii: S0024-3205(23)00772-5. [Epub ahead of print] 122137

Metabolomics and mitochondrial dysfunction in cardiometabolic disease.

Abhishek Shastry, Kimberly Dunham-Snary.

  Circulating metabolites are indicators of systemic metabolic dysfunction and can be detected through contemporary techniques in metabolomics. These metabolites are involved in numerous mitochondrial metabolic processes including glycolysis, fatty acid β-oxidation, and amino acid catabolism, and changes in abundance of these metabolites is implicated in the pathogenesis of cardiometabolic diseases (CMDs). Epigenetic regulation and direct metabolite-protein interactions modulate the metabolism, both within cells and in the circulation. Dysfunction of multiple mitochondrial components stemming from mitochondrial DNA mutations are implicated in disease pathogenesis. This review will summarize the current state of knowledge regarding: i) the interactions between metabolites found within the mitochondrial environment during CMDs, ii) various metabolites' effects on cellular and systemic function, iii) how harnessing the power of metabolomic analyses represents the next frontier of precision medicine, and iv) how these concepts integrate to expand the clinical potential for translational cardiometabolic medicine.

Keywords:  Cardiometabolic disease; Circulating metabolites; Metabolic profiling; Metabolomics; Mitochondria; Redox balance

DOI:  https://doi.org/10.1016/j.lfs.2023.122137
Nat Rev Mol Cell Biol. 2023 Oct 02.

Mechanisms and regulation of human mitochondrial transcription.

Benedict G Tan, Claes M Gustafsson, Maria Falkenberg.

The expression of mitochondrial genes is regulated in response to the metabolic needs of different cell types, but the basic mechanisms underlying this process are still poorly understood. In this Review, we describe how different layers of regulation cooperate to fine tune initiation of both mitochondrial DNA (mtDNA) transcription and replication in human cells. We discuss our current understanding of the molecular mechanisms that drive and regulate transcription initiation from mtDNA promoters, and how the packaging of mtDNA into nucleoids can control the number of mtDNA molecules available for both transcription and replication. Indeed, a unique aspect of the mitochondrial transcription machinery is that it is coupled to mtDNA replication, such that mitochondrial RNA polymerase is additionally required for primer synthesis at mtDNA origins of replication. We discuss how the choice between replication-primer formation and genome-length RNA synthesis is controlled at the main origin of replication (OriH) and how the recent discovery of an additional mitochondrial promoter (LSP2) in humans may change this long-standing model.

DOI: https://doi.org/10.1038/s41580-023-00661-4
Free Radic Biol Med. 2023 Sep 28. pii: S0891-5849(23)00661-5. [Epub ahead of print]

p53 contributes to cardiovascular diseases via mitochondria dysfunction: A new paradigm.

Hao Wang, Wei Yu, Yibo Wang, Ruihao Wu, Yifei Dai, Ye Deng, Shijun Wang, Jinxiang Yuan, Rubin Tan.

  Cardiovascular diseases (CVDs) are leading causes of global mortality; however, their underlying mechanisms remain unclear. The tumor suppressor factor p53 has been extensively studied for its role in cancer and is also known to play an important role in regulating CVDs. Abnormal p53 expression levels and modifications contribute to the occurrence and development of CVDs. Additionally, mounting evidence underscores the critical involvement of mitochondrial dysfunction in CVDs. Notably, studies indicate that p53 abnormalities directly correlate with mitochondrial dysfunction and may even interact with each other. Encouragingly, small molecule inhibitors targeting p53 have exhibited remarkable effects in animal models of CVDs. Moreover, therapeutic strategies aimed at mitochondrial-related molecules and mitochondrial replacement therapy have demonstrated their advantageous potential. Therefore, targeting p53 or mitochondria holds immense promise as a pioneering therapeutic approach for combating CVDs. In this comprehensive review, we delve into the mechanisms how p53 influences mitochondrial dysfunction, including energy metabolism, mitochondrial oxidative stress, mitochondria-induced apoptosis, mitochondrial autophagy, and mitochondrial dynamics, in various CVDs. Furthermore, we summarize and discuss the potential significance of targeting p53 or mitochondria in the treatment of CVDs.

Keywords:  Cardiovascular diseases; Mitochondria; Mitochondrial dynamics; Mitochondrial transplantation; Mitophagy; ROS; p53

DOI:  https://doi.org/10.1016/j.freeradbiomed.2023.09.036
Methods Mol Biol. 2024 ;2711 241-256

Evaluation of Glycolysis and Mitochondrial Function in Endothelial Cells Using the Seahorse Analyzer.

Zeinab Y Motawe, Salma S Abdelmaboud, Jerome W Breslin.

  Endothelial bioenergetics have emerged as a key regulator of endothelial barrier function. Glycolytic parameters have been linked to barrier enhancement, and interruption with mitochondrial complexes was shown to disrupt endothelial barrier. Therefore, a new technology that has been introduced to assess bioenergetics and metabolism has also made it possible to determine roles of specific energy production pathways in endothelial health. The Seahorse extracellular flux analysis by Agilent technologies is a state of the art tool that has been more frequently used to evaluate bioenergetics of endothelial cells. This chapter includes details about different assays that can be used to study endothelial cells using the Seahorse analyzer and how interpretation of the results can provide novel insight about endothelial metabolism.

Keywords:  ATP rate; Endothelial barrier; Endothelium; Glycolysis; Metabolism; Mitochondria; Seahorse

DOI:  https://doi.org/10.1007/978-1-0716-3429-5_20
Cell Biosci. 2023 Sep 30. 13(1): 182

NADH elevation during chronic hypoxia leads to VHL-mediated HIF-1α degradation via SIRT1 inhibition.

Hyun-Yoo Joo, Jin Kyu Jung, Mi-Yeon Kim, Seon Rang Woo, Jae Min Jeong, Eun-Ran Park, Yong-Min Kim, Joong-Jean Park, Joon Kim, Miyong Yun, Hyun-Jin Shin, Kee-Ho Lee.

   BACKGROUND: Under conditions of hypoxia, cancer cells with hypoxia inducible factor-1α (HIF-1α) from heterogeneous tumor cells show greater aggression and progression in an effort to compensate for harsh environmental conditions. Extensive study on the stability of HIF-1α under conditions of acute hypoxia in cancer progression has been conducted, however, understanding of its involvement during the chronic phase is limited.
METHODS: In this study, we investigated the effect of SIRT1 on HIF1 stability in a typical chronic hypoxic conditon that maintains cells for 24 h under hypoxia using Western blotting, co-IP, measurement of intracellular NAD + and NADH levels, semi-quantitative RT-PCR analysis, invasion assay, gene knockdown.
RESULTS: Here we demonstrated that the high concentration of pyruvate in the medium, which can be easily overlooked, has an effect on the stability of HIF-1α. We also demonstrated that NADH functions as a signal for conveyance of HIF-1α degradation via the SIRT1 and VHL signaling pathway under conditions of chronic hypoxia, which in turn leads to attenuation of hypoxically strengthened invasion and angiogenic activities. A steep increase in the level of NADH occurs during chronic hypoxia, leading to upregulation of acetylation and degradation of HIF-1α via inactivation of SIRT1. Of particular interest, p300-mediated acetylation at lysine 709 of HIF-1α is recogonized by VHL, which leads to degradation of HIF-1α via ubiquitin/proteasome machinary under conditions of chronic hypoxia. In addition, we demonstrated that NADH-elevation-induced acetylation and subsequent degradation of HIF-1α was independent of proline hydroxylation.
CONCLUSIONS: Our findings suggest a critical role of SIRT1 as a metabolic sensor in coordination of hypoxic status via regulation of HIF-1α stability. These results also demonstrate the involvement of VHL in degradation of HIF-1α through recognition of PHD-mediated hydroxylation in normoxia and p300-mediated HIF-1α acetylation in hypoxia.

Keywords:  Angiogenesis; Chronic hypoxia; HIF-1α degradation; Invasion; NADH elevation; SIRT1; VHL

DOI:  https://doi.org/10.1186/s13578-023-01130-3
Pulm Circ. 2023 Oct;13(4): e12293

Pulmonary arterial hypertension drugs can partially restore altered angiogenic capacities in bmpr2-silenced human lung microvascular endothelial cells.

Birger Tielemans, Allard Wagenaar, Catharina Belge, Marion Delcroix, Rozenn Quarck.

  Mutations in the bone morphogenetic protein receptor type 2 (bmpr2) gene and signaling pathway impairment are observed in heritable and idiopathic pulmonary arterial hypertension (PAH). In PAH, endothelial dysfunction is currently handled by drugs targeting the endothelin-1 (ET-1), nitric oxide (NO), and prostacyclin (PGI2) pathways. The role of angiogenesis in the disease process and the effect of PAH therapies on dysregulated angiogenesis remain inconclusive. We aim to investigate in vitro whether (i) bmpr2 silencing can impair angiogenic capacity of human lung microvascular endothelial cells (HLMVECs) and (ii) PAH therapies can restore them. The effects of macitentan (ET-1), tadalafil (NO), and selexipag (PGI2), on BMPRII pathway activation, endothelial barrier function, and angiogenesis were investigated in bmpr2-silenced HLMVECs. Stable bmpr2 silencing resulted in impaired migration and tube formation in vitro capacity. Inhibition of ET-1 pathway was able to partially restore tube formation in bmpr2-silenced HLMVECs, whereas none of the therapies was able to restore endothelial barrier function, no deleterious effects were observed. Our findings highlight the potential role of BMPRII signaling pathway in driving pulmonary endothelial cell angiogenesis. In addition, PAH drugs display limited effects on endothelial function when BMPRII is impaired, suggesting that innovative therapeutic strategies targeting BMPRII signaling are needed to better rescue endothelial dysfunction in PAH.

Keywords:  PAH drugs; endothelial barrier function; endothelial bmpr2 silencing; in vitro angiogenesis; pulmonary hypertension

DOI:  https://doi.org/10.1002/pul2.12293
Free Radic Biol Med. 2023 Sep 25. pii: S0891-5849(23)00654-8. [Epub ahead of print]208 771-779

The glyoxylate shunt protein ICL-1 protects from mitochondrial superoxide stress through activation of the mitochondrial unfolded protein response.

Guoqiang Wang, Ricardo Laranjeiro, Stephanie LeValley, Jeremy M Van Raamsdonk, Monica Driscoll.

Disrupting mitochondrial superoxide dismutase (SOD) causes neonatal lethality in mice and death of flies within 24 h after eclosion. Deletion of mitochondrial sod genes in C. elegans impairs fertility as well, but surprisingly is not detrimental to survival of progeny generated. The comparison of metabolic pathways among mouse, flies and nematodes reveals that mice and flies lack the glyoxylate shunt, a shortcut that bypasses part of the tricarboxylic acid (TCA) cycle. Here we show that ICL-1, the sole protein that catalyzes the glyoxylate shunt, is critical for protection against embryonic lethality resulting from elevated levels of mitochondrial superoxide. In exploring the mechanism by which ICL-1 protects against ROS-mediated embryonic lethality, we find that ICL-1 is required for the efficient activation of mitochondrial unfolded protein response (UPRmt) and that ATFS-1, a key UPRmt transcription factor and an activator of icl-1 gene expression, is essential to limit embryonic/neonatal lethality in animals lacking mitochondrial SOD. In sum, we identify a biochemical pathway that highlights a molecular strategy for combating toxic mitochondrial superoxide consequences in cells.

DOI: https://doi.org/10.1016/j.freeradbiomed.2023.09.029
Exp Biol Med (Maywood). 2023 Oct 03. 15353702231194344

Alteration of endothelial permeability ensures cardiomyocyte survival from ischemic insult in the subendocardium of the heart.

Qing Chu, Xin Song, Ying Xiao, Y James Kang.

  Previous studies have shown that cardiomyocytes in the subendocardial region of myocardium survive from ischemic insult. This study was undertaken to explore possible mechanisms for the survival of these cardiomyocytes, focusing on changes in endothelial cells (ECs) and blood supply. C57/B6 mice were subjected to permanent ligation of left anterior descending (LAD) coronary artery to induce myocardial ischemia (MI). The hearts were harvested at 1, 4, and 7 days post MI and examined for histological changes. It was found that the survival of cardiomyocytes was associated with a preservation of ECs in the subendocardial region, as revealed by EC-specific tdTomato expression transgenic mice (Tie2tdTomato). However, the EC selective proteins, PECAM1 and VEGFR2, were significantly depressed in these ECs. Consequently, the ratio of PECAM1/tdTomato was significantly decreased, indicating a transformation from PECAM1+ ECs to PECAM1- ECs. Furthermore, EC junction protein, VE-cadherin, was not only depressed but also disassociated from PECAM1 in the same region. These changes led to an increase in EC permeability, as evidenced by increased blood infiltration in the subendocardial region. Thus, the increase in the permeability of ECs due to their transformation in the subendocardial region allows blood infiltration, creating a unique microenvironment and ensuring the survival of cardiomyocytes under ischemic conditions.

Keywords:  Myocardial ischemia; PECAM1; VE-cadherin; cardiomyocytes; endothelial cells; permeability

DOI:  https://doi.org/10.1177/15353702231194344
Biomed Pharmacother. 2023 Oct 04. pii: S0753-3322(23)01450-6. [Epub ahead of print]167 115652

Mitochondrial dysfunction: A fatal blow in depression.

Yu Song, Huan Cao, Chengchao Zuo, Zhongya Gu, Yaqi Huang, Jinfeng Miao, Yufeng Fu, Yu Guo, Yongsheng Jiang, Furong Wang.

  Mitochondria maintain the normal physiological function of nerve cells by producing sufficient cellular energy and performing crucial roles in maintaining the metabolic balance through intracellular Ca2+ homeostasis, oxidative stress, and axonal development. Depression is a prevalent psychiatric disorder with an unclear pathophysiology. Damage to the hippocampal neurons is a key component of the plasticity regulation of synapses and plays a critical role in the mechanism of depression. There is evidence suggesting that mitochondrial dysfunction is associated with synaptic impairment. The maintenance of mitochondrial homeostasis includes quantitative maintenance and quality control of mitochondria. Mitochondrial biogenesis produces new and healthy mitochondria, and mitochondrial dynamics cooperates with mitophagy to remove damaged mitochondria. These processes maintain mitochondrial population stability and exert neuroprotective effects against early depression. In contrast, mitochondrial dysfunction is observed in various brain regions of patients with major depressive disorders. The accumulation of defective mitochondria accelerates cellular nerve dysfunction. In addition, impaired mitochondria aggravate alterations in the brain microenvironment, promoting neuroinflammation and energy depletion, thereby exacerbating the development of depression. This review summarizes the influence of mitochondrial dysfunction and the underlying molecular pathways on the pathogenesis of depression. Additionally, we discuss the maintenance of mitochondrial homeostasis as a potential therapeutic strategy for depression.

Keywords:  Major depressive disorder; Mitochondrial dysfunction; Mitochondrial quality control; Neuroinflammation

DOI:  https://doi.org/10.1016/j.biopha.2023.115652
Cell Mol Biol Lett. 2023 Sep 30. 28(1): 76

Oxidative stress as a key modulator of cell fate decision in osteoarthritis and osteoporosis: a narrative review.

Jana Riegger, Astrid Schoppa, Leonie Ruths, Melanie Haffner-Luntzer, Anita Ignatius.

  During aging and after traumatic injuries, cartilage and bone cells are exposed to various pathophysiologic mediators, including reactive oxygen species (ROS), damage-associated molecular patterns, and proinflammatory cytokines. This detrimental environment triggers cellular stress and subsequent dysfunction, which not only contributes to the development of associated diseases, that is, osteoporosis and osteoarthritis, but also impairs regenerative processes. To counter ROS-mediated stress and reduce the overall tissue damage, cells possess diverse defense mechanisms. However, cellular antioxidative capacities are limited and thus ROS accumulation can lead to aberrant cell fate decisions, which have adverse effects on cartilage and bone homeostasis. In this narrative review, we address oxidative stress as a major driver of pathophysiologic processes in cartilage and bone, including senescence, misdirected differentiation, cell death, mitochondrial dysfunction, and impaired mitophagy by illustrating the consequences on tissue homeostasis and regeneration. Moreover, we elaborate cellular defense mechanisms, with a particular focus on oxidative stress response and mitophagy, and briefly discuss respective therapeutic strategies to improve cell and tissue protection.

Keywords:  Bone; Cartilage; Cell death; Cell fate decision; Mitochondrial dysfunction; Osteoarthritis; Osteoporosis; Oxidative stress; ROS; Senescence

DOI:  https://doi.org/10.1186/s11658-023-00489-y
Nat Rev Mol Cell Biol. 2023 Oct 02.

Mechanisms controlling cellular and systemic iron homeostasis.

Bruno Galy, Marcus Conrad, Martina Muckenthaler.

In mammals, hundreds of proteins use iron in a multitude of cellular functions, including vital processes such as mitochondrial respiration, gene regulation and DNA synthesis or repair. Highly orchestrated regulatory systems control cellular and systemic iron fluxes ensuring sufficient iron delivery to target proteins is maintained, while limiting its potentially deleterious effects in iron-mediated oxidative cell damage and ferroptosis. In this Review, we discuss how cells acquire, traffick and export iron and how stored iron is mobilized for iron-sulfur cluster and haem biogenesis. Furthermore, we describe how these cellular processes are fine-tuned by the combination of various sensory and regulatory systems, such as the iron-regulatory protein (IRP)-iron-responsive element (IRE) network, the nuclear receptor co-activator 4 (NCOA4)-mediated ferritinophagy pathway, the prolyl hydroxylase domain (PHD)-hypoxia-inducible factor (HIF) axis or the nuclear factor erythroid 2-related factor 2 (NRF2) regulatory hub. We further describe how these pathways interact with systemic iron homeostasis control through the hepcidin-ferroportin axis to ensure appropriate iron fluxes. This knowledge is key for the identification of novel therapeutic opportunities to prevent diseases of cellular and/or systemic iron mismanagement.

DOI: https://doi.org/10.1038/s41580-023-00648-1
Annu Rev Physiol. 2023 Oct 03.

The Mineralocorticoid Receptor in the Vasculature: Friend or Foe?

Jaime Ibarrola, Iris Z Jaffe.

Originally described as the renal aldosterone receptor that regulates sodium homeostasis, it is now clear that mineralocorticoid receptors (MRs) are widely expressed, including in vascular endothelial and smooth muscle cells. Ample data demonstrate that endothelial and smooth muscle cell MRs contribute to cardiovascular disease in response to risk factors (aging, obesity, hypertension, atherosclerosis) by inducing vasoconstriction, vascular remodeling, inflammation, and oxidative stress. Extrapolating from its role in disease, evidence supports beneficial roles of vascular MRs in the context of hypotension by promoting inflammation, wound healing, and vasoconstriction to enhance survival from bleeding or sepsis. Advances in understanding how vascular MRs become activated are also reviewed, describing transcriptional, ligand-dependent, and ligand-independent mechanisms. By synthesizing evidence describing how vascular MRs convert cardiovascular risk factors into disease (the vascular MR as a foe), we postulate that the teleological role of the MR is to coordinate responses to hypotension (the MR as a friend). Expected final online publication date for the Annual Review of Physiology, Volume 86 is February 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

DOI: https://doi.org/10.1146/annurev-physiol-042022-015223
J Heart Lung Transplant. 2023 Sep 30. pii: S1053-2498(23)02056-9. [Epub ahead of print]

A Multi-omic and Multi-Species Analysis of Right Ventricular Dysfunction.

Jenna B Mendelson, Jacob D Sternbach, Michelle J Doyle, Lauren Mills, Lynn M Hartweck, Walt Tollison, John P Carney, Matthew T Lahti, Richard W Bianco, Rajat Kalra, Felipe Kazmirczak, Charles Hindmarch, Stephen L Archer, Kurt W Prins, Cindy M Martin.

   BACKGROUND: Right ventricular failure (RVF) is a leading cause of morbidity and mortality in multiple cardiovascular diseases, but there are no approved treatments for RVF as therapeutic targets are not clearly defined. Contemporary transcriptomic/proteomic evaluations of RVF are predominately conducted in small animal studies, and data from large animal models are sparse. Moreover, a comparison of the molecular mediators of RVF across species is lacking METHODS: Transcriptomics and proteomics analyses defined the molecular pathways associated with cardiac MRI-derived values of RV hypertrophy, dilation, and dysfunction in control and pulmonary artery banded (PAB) piglets (n=4). Publicly available data from rat monocrotaline-induced RVF and pulmonary arterial hypertension patients with preserved or impaired RV function were used to compare molecular responses across species.
RESULTS: PAB piglets displayed significant RV hypertrophy, dilation, and dysfunction as quantified by cMRI. Transcriptomic and proteomic analyses identified multiple pathways associated with RV dysfunction and remodeling in PAB pigs. Surprisingly, disruptions in fatty acid oxidation (FAO) and electron transport chain (ETC) proteins were different across the three species. FAO and ETC proteins and transcripts were mostly downregulated in rats, but were predominately upregulated in PAB pigs, which more closely matched the human response. All three species exhibited similar dysregulation of the dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy pathways.
CONCLUSIONS: The pig PAB metabolic molecular signature was more similar to human RVF than rodents. These data suggest there may be divergent molecular responses of RVF across species, and that pigs may more accurately recapitulate metabolic aspects of human RVF.

Keywords:  Cardiac MRI; Proteomics; RV; Transcriptomics

DOI:  https://doi.org/10.1016/j.healun.2023.09.020
JACC Basic Transl Sci. 2023 Sep;8(9): 1198-1211

An Unbiased Screen Identified the Hsp70-BAG3 Complex as a Regulator of Myosin-Binding Protein C3.

Andrea D Thompson, Marcus J Wagner, Juliani Rodriguez, Alok Malhotra, Steve Vander Roest, Ulla Lilienthal, Hao Shao, Mathav Vignesh, Keely Weber, Jaime M Yob, Benjamin L Prosser, Adam S Helms, Jason E Gestwicki, David Ginsburg, Sharlene M Day.

  Variants in the gene myosin-binding protein C3 (MYBPC3) account for approximately 50% of familial hypertrophic cardiomyopathy (HCM), leading to reduced levels of myosin-binding protein C3 (MyBP-C), the protein product made by gene MYBPC3. Elucidation of the pathways that regulate MyBP-C protein homeostasis could uncover new therapeutic strategies. Toward this goal, we screened a library of 2,426 bioactive compounds and identified JG98, an allosteric modulator of heat shock protein 70 that inhibits interaction with Bcl-2-associated athanogene (BAG) domain co-chaperones. JG98 reduces MyBP-C protein levels. Furthermore, genetic reduction of BAG3 phenocopies treatment with JG-98 by reducing MYBP-C protein levels.. Thus, an unbiased compound screen identified the heat shock protein 70-BAG3 complex as a regulator of MyBP-C stability.

Keywords:  BAG3; MYBPC3; hypertrophic cardiomyopathy; molecular chaperones

DOI:  https://doi.org/10.1016/j.jacbts.2023.04.009
Methods Mol Biol. 2024 ;2711 235-240

Determination of Tight Junction Integrity in Brain Endothelial Cells Based on Tight Junction Protein Expression.

Himakarnika Alluri, Chander Sekhar Peddaboina, Binu Tharakan.

  Blood-brain barrier (BBB) dysfunction and hyperpermeability that occurs following traumatic and ischemic insults lead to various downstream ill effects such as cerebral edema and elevation of intracranial pressure. The inter-endothelial tight junctions that consist of tight junction proteins are critical regulators of BBB dysfunctions and hyperpermeability. The major tight junction-associated proteins of the BBB are occludin, claudins, and junctional adhesion molecules that are intracellularly linked to the adaptor protein zonula occludens-1 (ZO-1). Quantitative measurement of tight junction-associated proteins provides valuable insight into barrier integrity and mechanisms that regulate microvascular hyperpermeability. Western blot analysis is a commonly used method to separate and identify proteins in a mixture using gel electrophoresis. Understanding the changes in the expression of one or more of these proteins is critical to evaluating barrier integrity and permeability in health and disease. Furthermore, studying them will provide insight into the associated downstream signaling pathways and evaluation of therapeutic approaches for regulating BBB permeability. Herein, we have described the protocol for immunoblot analysis of ZO-1 as an indicator of tight junction integrity in brain microvascular endothelial cells.

Keywords:  Blood-brain barrier permeability; Endothelial tight junctions; Tight junction proteins; Zonula occludens-1

DOI:  https://doi.org/10.1007/978-1-0716-3429-5_19
Mol Ther Nucleic Acids. 2023 Dec 12. 34 102036

The decoy oligodeoxynucleotide against HIF-1α and STAT5 ameliorates atopic dermatitis-like mouse model.

Mi-Gyeong Gwon, Jaechan Leem, Hyun-Jin An, Hyemin Gu, Seongjae Bae, Jong Hyun Kim, Kwan-Kyu Park.

  Atopic dermatitis (AD) is a common inflammatory skin disease caused by an immune disorder. Mast cells are known to be activated and granulated to maintain an allergic reaction, including rhinitis, asthma, and AD. Although hypoxia-inducible factor-1 alpha (HIF-1α) and signal transducer and activator of transcription 5 (STAT5) play crucial roles in mast cell survival and granulation, their effects need to be clarified in allergic disorders. Thus, we designed decoy oligodeoxynucleotide (ODN) synthetic DNA, without open ends, containing complementary sequences for HIF-1α and STAT5 to suppress the transcriptional activities of HIF-1α and STAT5. In this study, we demonstrated the effects of HIF-1α/STAT5 ODN using AD-like in vivo and in vitro models. The HIF-1α/STAT5 decoy ODN significantly alleviated cutaneous symptoms similar to AD, including morphology changes, immune cell infiltration, skin barrier dysfunction, and inflammatory response. In the AD model, it also inhibited mast cell infiltration and degranulation in skin tissue. These results suggest that the HIF-1α/STAT5 decoy ODN ameliorates the AD-like disorder and immunoglobulin E (IgE)-induced mast cell activation by disrupting HIF-1α/STAT5 signaling pathways. Taken together, these findings suggest the possibility of HIF-1α/STAT5 as therapeutic targets and their decoy ODN as a potential therapeutic tool for AD.

Keywords:  HIF-1α; MT: Oligonucleotides: Therapies and Applications; STAT5; atopic dermatitis; decoy oligodeoxynucleotide; mast cell

DOI:  https://doi.org/10.1016/j.omtn.2023.102036
Elife. 2023 10 03. pii: RP88189. [Epub ahead of print]12

Novel regulators of islet function identified from genetic variation in mouse islet Ca2+ oscillations.

Christopher H Emfinger, Lauren E Clark, Brian Yandell, Kathryn L Schueler, Shane P Simonett, Donnie S Stapleton, Kelly A Mitok, Matthew J Merrins, Mark P Keller, Alan D Attie.

  Insufficient insulin secretion to meet metabolic demand results in diabetes. The intracellular flux of Ca2+ into β-cells triggers insulin release. Since genetics strongly influences variation in islet secretory responses, we surveyed islet Ca2+ dynamics in eight genetically diverse mouse strains. We found high strain variation in response to four conditions: (1) 8 mM glucose; (2) 8 mM glucose plus amino acids; (3) 8 mM glucose, amino acids, plus 10 nM glucose-dependent insulinotropic polypeptide (GIP); and (4) 2 mM glucose. These stimuli interrogate β-cell function, α- to β-cell signaling, and incretin responses. We then correlated components of the Ca2+ waveforms to islet protein abundances in the same strains used for the Ca2+ measurements. To focus on proteins relevant to human islet function, we identified human orthologues of correlated mouse proteins that are proximal to glycemic-associated single-nucleotide polymorphisms in human genome-wide association studies. Several orthologues have previously been shown to regulate insulin secretion (e.g. ABCC8, PCSK1, and GCK), supporting our mouse-to-human integration as a discovery platform. By integrating these data, we nominate novel regulators of islet Ca2+ oscillations and insulin secretion with potential relevance for human islet function. We also provide a resource for identifying appropriate mouse strains in which to study these regulators.

Keywords:  calcium imaging; cell biology; diabetes; genetics; genomics; insulin secretion; islet; mouse; mouse genetics; β-cell

DOI:  https://doi.org/10.7554/eLife.88189
J Cancer Res Clin Oncol. 2023 Oct 02.

Multi-omics analysis revealed the mitochondrial-targeted drug combination to suppress the development of lung cancer.

Chaoqun Li, Yanfei Zhang, Qing Xia, Bingjie Hao, Yifan Hong, Liduo Yue, Tiansheng Zheng, Ming Li, Lihong Fan.

   PURPOSE: The incidence and mortality of lung cancer are continuously rising in recent years. Mitochondrial energy metabolism malfunction is found to be crucial in cancer proliferation and bioenergetic reprogramming, especially for lung cancer. In this study, we attempted to use mitochondrial-targeted drug therapy to change the energy metabolism pattern of cancer cells to inhibit the development of lung cancer, and investigated its mechanism of action and key targets through multi-omics studies.
METHODS: In this study, we established the in vivo tumor mouse mode, treated mice with multiple mitochondrial-targeted drug combinations and DDP, severally. Then, we investigated the differences between the 7-drug group with the control group and the DDP treatment group by transcriptomics, proteomics and metabolomics to find the therapeutic targets.
RESULTS: We found that mitochondria-targeting drug cocktail therapy, especially the 7-drug regimen, effectively improved mitochondrial metabolism, changed energy supply patterns in lung cancer cells, significantly increased NK cells in tumor tissues, and decreased tumor markers in plasma. Multi-omics analysis informed that the combination of 7-drug could up-regulate mitochondrial oxidative phosphorylation, ATP synthesis and autophagy related genes, and down-regulate proliferation and immune-related genes compared with the control group. By further mapping the protein interaction network, we identified a key target for 7-drug therapy to reverse tumor metabolic reprogramming and validated it in metabolomics.
CONCLUSIONS: Mitochondrial-targeted drug cocktail therapy can effectively inhibit the occurrence and development of tumors, through the reprogramming of energy metabolism and the increase in immune cells in tumor tissues. Thus, we provide a novel approach for the treatment of lung cancer and present evidence-based clues for the combined use of targeted mitochondrial drugs.

Keywords:  Cocktail therapy; Energy metabolism; Lung cancer; Mitochondria; Mitochondria targeting drug; Omics analysis

DOI:  https://doi.org/10.1007/s00432-023-05376-9
RNA Biol. 2023 Jan;20(1): 715-736

Maturation of small nucleolar RNAs: from production to function.

Sarah F Webster, Homa Ghalei.

  Small Nucleolar RNAs (snoRNAs) are an abundant group of non-coding RNAs with well-defined roles in ribosomal RNA processing, folding and chemical modification. Besides their classic roles in ribosome biogenesis, snoRNAs are also implicated in several other cellular activities including regulation of splicing, transcription, RNA editing, cellular trafficking, and miRNA-like functions. Mature snoRNAs must undergo a series of processing steps tightly regulated by transiently associating factors and coordinated with other cellular processes including transcription and splicing. In addition to their mature forms, snoRNAs can contribute to gene expression regulation through their derivatives and degradation products. Here, we review the current knowledge on mechanisms of snoRNA maturation, including the different pathways of processing, and the regulatory mechanisms that control snoRNA levels and complex assembly. We also discuss the significance of studying snoRNA maturation, highlight the gaps in the current knowledge and suggest directions for future research in this area.

Keywords:  Small nucleolar RNA; non-coding RNA processing; snoRNA; snoRNA maturation; snoRNP assembly

DOI:  https://doi.org/10.1080/15476286.2023.2254540
Mol Neurobiol. 2023 Sep 30.

Hypoxia-Induced miR-101 Impairs Endothelial Barrier Integrity Through Altering VE-Cadherin and Claudin-5.

Astha Shukla, Utkarsh Bhardwaj, Apoorva, Pankaj Seth, Sunit K Singh.

  Stroke is a life-threatening medical condition across the world that adversely affects the integrity of the blood-brain barrier (BBB). The brain microvascular endothelial cells are the important constituent of the BBB. These cells line the blood vessels and form a semipermeable barrier. Disruptions in adherens junction and tight junction proteins of brain microvascular endothelial cells compromise the integrity of BBB. The Vascular Endothelial (VE)-cadherin is an integral adherens junction protein required for the establishment and maintenance of the endothelial barrier integrity. This study aims to investigate the role of miRNA in hypoxia-induced endothelial barrier disruption. In this study, brain endothelial cells were exposed to hypoxic conditions for different time points. Western blotting, overexpression and knockdown of miRNA, real-time PCR, TEER, and sodium fluorescein assay were used to examine the effect of hypoxic conditions on brain endothelial cells. Hypoxic exposure was validated using HIF-1α protein. Exposure to hypoxic conditions resulted to a significant decrease in endothelial barrier resistance and an increase in sodium fluorescein migration across the endothelial barrier. Reduction in endothelial barrier resistance demonstrated compromised barrier integrity, whereas the increase in migration of sodium fluorescein across the barrier indicated the increase in barrier permeability. The present study revealed microRNA-101 decreases the expression of VE-cadherin and claudin-5 in brain endothelial cells exposed to the hypoxic conditions.

Keywords:  Adherens junction; CNS; Stroke; Tight junction; hCMEC/D3

DOI:  https://doi.org/10.1007/s12035-023-03662-8
Hum Genet. 2023 Oct 02.

Long noncoding RNAs as versatile molecular regulators of cellular stress response and homeostasis.

Julia Scholda, Thi Thuy Anh Nguyen, Florian Kopp.

Normal cell and body functions need to be maintained and protected against endogenous and exogenous stress conditions. Different cellular stress response pathways have evolved that are utilized by mammalian cells to recognize, process and overcome numerous stress stimuli in order to maintain homeostasis and to prevent pathophysiological processes. Although these stress response pathways appear to be quite different on a molecular level, they all have in common that they integrate various stress inputs, translate them into an appropriate stress response and eventually resolve the stress by either restoring homeostasis or inducing cell death. It has become increasingly appreciated that non-protein-coding RNA species, such as long noncoding RNAs (lncRNAs), can play critical roles in the mammalian stress response. However, the precise molecular functions and underlying modes of action for many of the stress-related lncRNAs remain poorly understood. In this review, we aim to provide a framework for the categorization of mammalian lncRNAs in stress response and homeostasis based on their experimentally validated modes of action. We describe the molecular functions and physiological roles of selected lncRNAs and develop a concept of how lncRNAs can contribute as versatile players in mammalian stress response and homeostasis. These concepts may be used as a starting point for the identification of novel lncRNAs and lncRNA functions not only in the context of stress, but also in normal physiology and disease.

DOI: https://doi.org/10.1007/s00439-023-02604-7
Mol Med Rep. 2023 Nov;pii: 224. [Epub ahead of print]28(5):

Plasma metabonomic study on the effect of Para‑hydroxybenzaldehyde intervention in a rat model of transient focal cerebral ischemia.

Xinglin Yu, Yuan Luo, Liping Yang, Xiaohua Duan.

  Gastrodia elata Blume has been widely used to treat various central and peripheral nerve diseases, and Para‑hydroxybenzaldehyde (PHBA) is one of the indicated components suggested to provide a neuroprotective effect. In our previous, it was shown that PHBA protected mitochondria against cerebral ischemia‑reperfusion (I/R) injury in rats. In the present study, how PHBA regulated the metabolic mechanism in blood following cerebral I/R was assessed to identify an effective therapeutic target for the prevention and treatment of ischemic stroke (IS). First, a rat model of cerebral ischemia‑reperfusion injury was established via middle cerebral artery occlusion/reperfusion (MCAO/R). The therapeutic effect of PHBA on brain I/R was evaluated by assessing the neurological function score, triphenyl tetrazolium chloride, hematoxylin and eosin, and Nissl staining. Next, a non‑targeted metabolomic based on high‑performance liquid chromatography quadrupole time‑of‑flight mass spectrometry was established to identify differential metabolites. Finally, a targeted metabolic spectrum was analyzed and the potential therapeutic targets were verified by Western blotting. The results showed that the neurological function score, cerebral infarction area, hippocampal morphology, and the number of neurons in the PHBA group were significantly improved compared with the model group. Metabonomic analysis showed that 13 different metabolites were identified between the model and PHBA group, which may be involved in the 'tricarboxylic acid cycle', 'glutathione metabolism', and 'mutual transformation of pentose and glucuronates', amongst others. Among these, the levels of the most significant differential metabolite, dGMP, decreased significantly following PHBA treatment. Western blotting was used to verify the expression of membrane‑associated guanosine kinase PSD‑95 and the subunit of glutamate AMPA receptor GluA1, which significantly increased after PHBA treatment. In addition, it was also found that PHBA increased the expression of the light chain‑3 protein and autophagy effector protein 1, whilst the expression of sequestosome‑1 decreased, indicating that PHBA promoted autophagy. Similarly, in TUNEL staining and detection of apoptosis‑related proteins, it was found that MCAO/R upregulated the expression of Bax and cleaved‑caspase‑3 whilst downregulating the expression of Bcl‑2 and increasing the apoptosis of hippocampal neurons; PHBA reversed this situation. These results suggest that cerebral I/R causes postsynaptic dysfunction by disrupting the interaction between PSD‑95 and AMPARs, and the inhibition of the autophagy system eventually leads to the apoptosis of hippocampal neurons.

Keywords:  PSD‑95; P‑hydroxybenzaldehyde; apoptosis; autophagy; ischemic stroke; metabolomics

DOI:  https://doi.org/10.3892/mmr.2023.13111
Annu Rev Pathol. 2023 Oct 03.

Control of Cell Death in Health and Disease.

Nobuhiko Kayagaki, Joshua D Webster, Kim Newton.

Apoptosis, necroptosis, and pyroptosis are genetically programmed cell death mechanisms that eliminate obsolete, damaged, infected, and self-reactive cells. Apoptosis fragments cells in a manner that limits immune cell activation, whereas the lytic death programs of necroptosis and pyroptosis release proinflammatory intracellular contents. Apoptosis fine-tunes tissue architecture during mammalian development, promotes tissue homeostasis, and is crucial for averting cancer and autoimmunity. All three cell death mechanisms are deployed to thwart the spread of pathogens. Disabling regulators of cell death signaling in mice has revealed how excessive cell death can fuel acute or chronic inflammation. Here we review strategies for modulating cell death in the context of disease. For example, BCL-2 inhibitor venetoclax, an inducer of apoptosis, is approved for the treatment of certain hematologic malignancies. By contrast, inhibition of RIPK1, NLRP3, GSDMD, or NINJ1 to limit proinflammatory cell death and/or the release of large proinflammatory molecules from dying cells may benefit patients with inflammatory diseases. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 19 is January 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

DOI: https://doi.org/10.1146/annurev-pathmechdis-051022-014433
Int J Biol Sci. 2023 ;19(14): 4657-4671

Pgam5-mediated PHB2 dephosphorylation contributes to endotoxemia-induced myocardial dysfunction by inhibiting mitophagy and the mitochondrial unfolded protein response.

Chen Cai, Ziying Li, Zemao Zheng, Zhongzhou Guo, Qian Li, Shuxian Deng, Nengxian Shi, Qing Ou, Hao Zhou, Zhigang Guo, Zhongqing Chen, Hang Zhu.

  Numerous mitochondrial abnormalities are reported to result from excessive inflammation during endotoxemia. Prohibitin 2 (PHB2) and phosphoglycerate mutase 5 (Pgam5) have been associated with altered mitochondrial homeostasis in several cardiovascular diseases; however, their role in endotoxemia-related myocardial dysfunction has not been explored. Our experiments were aimed to evaluate the potential contribution of Pgam5 and PHB2 to endotoxemia-induced mitochondrial dysfunction in cardiomyocytes, with a focus on two endogenous protective programs that sustain mitochondrial integrity, namely mitophagy and the mitochondrial unfolded protein response (UPRmt). We found that PHB2 transgenic mice are resistant to endotoxemia-mediated myocardial depression and mitochondrial damage. Our assays indicated that PHB2 overexpression activates mitophagy and the UPRmt, which maintains mitochondrial metabolism, prevents oxidative stress injury, and enhances cardiomyocyte viability. Molecular analyses further showed that Pgam5 binds to and dephosphorylates PHB2, resulting in cytosolic translocation of mitochondrial PHB2. Silencing of Pgam5 or transfection of a phosphorylated PHB2 mutant in mouse HL-1 cardiomyocytes prevented the loss of mitochondrially-localized PHB2 and activated mitophagy and UPRmt in the presence of LPS. Notably, cardiomyocyte-specific deletion of Pgam5 in vivo attenuated LPS-mediated myocardial dysfunction and preserved cardiomyocyte viability. These findings suggest that Pgam5/PHB2 signaling and mitophagy/UPRmt are potential targets for the treatment of endotoxemia-related cardiac dysfunction.

Keywords:  PHB2; Pgam5; endotoxemia-related cardiac dysfunction

DOI:  https://doi.org/10.7150/ijbs.85767
JCI Insight. 2023 Oct 03. pii: e173716. [Epub ahead of print]

CCR5 drives NK cell-associated airway damage in pulmonary ischemia-reperfusion injury.

Jesse Santos, Ping Wang, Avishai Shemesh, Fengchun Liu, Tasha Tsao, Oscar A Aguilar, Simon J Cleary, Jonathan P Singer, Ying Gao, Steven R Hays, Jeffrey Golden, Lorriana E Leard, Mary Ellen Kleinhenz, Nicholas A Kolaitis, Rupal J Shah, Aida Venado, Jasleen Kukreja, S Sam Weigt, John A Belperio, Lewis L Lanier, Mark R Looney, John R Greenland, Daniel R Calabrese.

  Primary graft dysfunction (PGD) limits clinical benefit after lung transplantation, a life-prolonging therapy for patients with end-stage disease. PGD is the clinical syndrome resulting from pulmonary ischemia-reperfusion injury (IRI), driven by innate immune inflammation. We recently demonstrated a key role for NK cells in the airways of mouse models and human tissue samples of IRI. Here we used 2 mouse models paired with human lung transplant samples to investigate the mechanisms whereby NK cells migrate to the airways to mediate lung injury. We demonstrate that chemokine receptor ligand transcripts and proteins are increased in mouse and human disease. CCR5 ligand transcripts were correlated with NK cell gene signatures independent of NK cell CCR5 ligand secretion. NK cells expressing CCR5 were increased in the lung and airways during IRI and had increased markers of tissue residency and maturation. Allosteric CCR5 drug blockade reduced the migration of NK cells to the site of injury. CCR5 blockade also blunted quantitative measures of experimental IRI. Additionally, in human lung transplant bronchoalveolar lavage samples, we found that CCR5 ligand was associated with increased patient morbidity and that the CCR5 receptor was increased in expression on human NK cells following PGD. These data support a potential mechanism for NK cell migration during lung injury and identify a plausible preventative treatment for PGD.

Keywords:  Chemokines; Innate immunity; NK cells; Pulmonology; Transplantation

DOI:  https://doi.org/10.1172/jci.insight.173716
G3 (Bethesda). 2023 Oct 04. pii: jkad229. [Epub ahead of print]

Characterizing genetic variation in the regulation of the ER stress response through computational and cis-eQTL analyses.

Nikki D Russell, Lynn B Jorde, Clement Y Chow.

  Misfolded proteins in the endoplasmic reticulum (ER) elicit the ER stress response, a large transcriptional response driven by three well-characterized transcription factors. This transcriptional response is variable across different genetic backgrounds. One mechanism in which genetic variation can lead to transcriptional variability in the ER stress response is through altered binding and activity of the three main transcription factors: XBP1, ATF6, and ATF4. This work attempts to better understand this mechanism by first creating a computational pipeline to identify potential binding sites throughout the human genome. We utilized GTEx datasets to identify cis- eQTLs that fall within predicted transcription factor binding sites (TFBSs). We also utilized the ClinVar database to compare the number of pathogenic versus benign variants at different positions of the binding motifs. Finally, we performed a cis- eQTL analysis on human cell lines experiencing ER stress to identify cis- eQTLs that regulate the variable ER stress response. The majority of these cis- eQTLs are unique to a given condition: control or ER stress. Some of these stress-specific cis- eQTLs fall within putative binding sites of the three main ER stress response transcription factors, providing a potential mechanism by which these cis- eQTLs might be impacting gene expression under ER stress conditions through altered TF binding. This study represents the first cis- eQTL analysis on human samples experiencing ER stress and is a vital step towards identifying the genetic components responsible for the variable ER stress response.

Keywords:   cis- eQTL; ER stress; genetic resource; genetic variation; transcriptional variability

DOI:  https://doi.org/10.1093/g3journal/jkad229