bims-bicyki 2022-01-09 papers

bims-bicyki

Biomed News

on Bicaudal-C1 and interactors in cystic kidney disease

Issue of 2022–01–09
nineteen papers selected by
Céline Gagnieux, École Polytechnique Fédérale de Lausanne

A Rare Case of Pelvic Organ Prolapse in a Nulliparous Female With Autosomal Dominant Polycystic Kidney Disease (ADPKD) and Polycystic Liver Disease (PLD).
Is autosomal dominant polycystic kidney disease an early sweet disease?
Primary cilia and ciliary signaling pathways in aging and age-related brain disorders.
Generation of heterozygous PKD1 mutant pigs exhibiting early-onset renal cyst formation.
Balancing the length of the distal tip by septins is key for stability and signalling function of primary cilia.
Mosaic PKHD1 in Polycystic Kidneys Caused Aberrant Protein Expression in the Mitochondria and Lysosomes.
Pepducin ICL1-9-Mediated β2-Adrenergic Receptor-Dependent Cardiomyocyte Contractility Occurs in a Gi Protein/ROCK/PKD-Sensitive Manner.
Identification of Two Novel Mutations in PKHD1 Gene from Two Families with Polycystic Kidney Disease by Whole Exome Sequencing.
Novel biomarkers of ciliary extracellular vesicles interact with ciliopathy and Alzheimer's associated proteins.
Deletion of kif3a in CK19 positive cells leads to primary cilia loss, biliary cell proliferation and cystic liver lesions in TAA-treated mice.
Numb inhibits migration and promotes proliferation of colon cancer cells via RhoA/ROCK signaling pathway repression.
How CEP164 ciliopathy mutations impair ciliogenesis.
Rho-Associated Kinase Inhibitor Eye Drops in challenging cataract surgery.
Combinations of deletion and missense variations of the dynein-2 DYNC2LI1 subunit found in skeletal ciliopathies cause ciliary defects.
Ion Channels of Cilia: Paramecium as a Model.
Inhibition of ROCK2 kinase activity improved behavioral deficits and reduced neuron damage in a DEACMP rat model.
CFTR deficiency aggravates Ang II induced vasoconstriction and hypertension by regulating Ca2+ influx and RhoA/Rock pathway in VSMCs.
Designing Single-Component Optogenetic Membrane Recruitment Systems: The Rho-Family GTPase Signaling Toolbox.
Nek4 regulates mitochondrial respiration and morphology.

Cureus. 2021 Nov;13(11): e20023

A Rare Case of Pelvic Organ Prolapse in a Nulliparous Female With Autosomal Dominant Polycystic Kidney Disease (ADPKD) and Polycystic Liver Disease (PLD).

Sharon Hechter, Nagapratap Ganta, Smriti Kochhar, Anish Kanukuntla, Priyaranjan Kata, James Turro, Pramil Cheriyath.

  Polycystic liver disease (PLD) is a condition that most often occurs in patients with autosomal dominant polycystic kidney disease (ADPKD) and less commonly as isolated liver disease. The presence of both conditions has proven to be a therapeutic challenge. Patients with ADPKD can suffer from significant renal and extra-renal complications and symptoms as a result of space-occupying cysts from polycystic kidney and liver enlargement. We present a case of ADPKD in a 56-year-old Caucasian female who developed pelvic organ prolapse, a rare complication, while also dealing with multiple other complications of ADPKD. Despite the high prevalence of ADPKD, complications such as pelvic organ prolapse have seldom been reported and discussed in the literature. The care team should do a prompt gynecological examination when they realize the burden of cysts becomes so large.

Keywords:  autosomal-dominant polycystic kidney disease; cyst; end-stage renal disease; pelvic organ prolapse; polycystic liver disease

DOI:  https://doi.org/10.7759/cureus.20023
Pediatr Nephrol. 2022 Jan 05.

Is autosomal dominant polycystic kidney disease an early sweet disease?

Angélique Dachy, Jean-Paul Decuypere, Rudi Vennekens, François Jouret, Djalila Mekahli.

  The clinical course of autosomal dominant polycystic kidney disease (ADPKD) starts in childhood. Evidence of the beneficial impact of early nephron-protective strategies and lifestyle modifications on ADPKD prognosis is accumulating. Recent studies have described the association of overweight and obesity with rapid disease progression in adults with ADPKD. Moreover, defective glucose metabolism and metabolic reprogramming have been reported in distinct ADPKD models highlighting these pathways as potential therapeutic targets in ADPKD. Several "metabolic" approaches are currently under evaluation in adults, including ketogenic diet, food restriction, and metformin therapy. No data are available on the impact of these approaches in childhood thus far. Yet, according to World Health Organization (WHO), we are currently facing a childhood obesity crisis with an increased prevalence of overweight/obesity in the pediatric population associated with a cardio-metabolic risk profile. The present review summarizes the knowledge about the role of glucose metabolism in the pathophysiology of ADPKD and underscores the possible harm of overweight and obesity in ADPKD especially in terms of long-term cardiovascular outcomes and renal prognosis.

Keywords:  Autosomal dominant polycystic kidney disease; Children; Glucose; Insulin; Obesity; Overweight

DOI:  https://doi.org/10.1007/s00467-021-05406-z
Neurobiol Dis. 2021 Dec 31. pii: S0969-9961(21)00356-9. [Epub ahead of print]163 105607

Primary cilia and ciliary signaling pathways in aging and age-related brain disorders.

Rong Ma, Naseer A Kutchy, Liang Chen, Douglas D Meigs, Guoku Hu.

  Brain disorders are characterized by the progressive loss of structure and function of the brain as a consequence of progressive degeneration and/or death of nerve cells. Aging is a major risk factor for brain disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and stroke. Various cellular and molecular events have been shown to play a role in the progress of neurodegenerative diseases. Emerging studies suggest that primary cilia could be a key regulator in brain diseases. The primary cilium is a singular cellular organelle expressed on the surface of many cell types, such as astrocytes and neurons in the mature brain. Primary cilia detect extracellular cues, such as Sonic Hedgehog (SHH) protein, and transduce these signals into cells to regulate various signaling pathways. Abnormalities in ciliary length and frequency (ratio of ciliated cells) have been implicated in various human diseases, including brain disorders. This review summarizes current findings and thoughts on the role of primary cilia and ciliary signaling pathways in aging and age-related brain disorders.

Keywords:  Aging; Alzheimer's disease; Amyotrophic lateral sclerosis; Hedgehog signaling; Notch signaling; Parkinson's disease; Primary cilia; Wnt signaling

DOI:  https://doi.org/10.1016/j.nbd.2021.105607
Lab Invest. 2022 Jan 03.

Generation of heterozygous PKD1 mutant pigs exhibiting early-onset renal cyst formation.

Masahito Watanabe, Kazuhiro Umeyama, Kazuaki Nakano, Hitomi Matsunari, Toru Fukuda, Kei Matsumoto, Susumu Tajiri, Shuichiro Yamanaka, Koki Hasegawa, Kazutoshi Okamoto, Ayuko Uchikura, Shuko Takayanagi, Masaki Nagaya, Takashi Yokoo, Hiromitsu Nakauchi, Hiroshi Nagashima.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disease, manifesting as the progressive development of fluid-filled renal cysts. In approximately half of all patients with ADPKD, end-stage renal disease results in decreased renal function. In this study, we used CRISPR-Cas9 and somatic cell cloning to produce pigs with the unique mutation c.152_153insG (PKD1insG/+). Pathological analysis of founder cloned animals and progeny revealed that PKD1insG/+ pigs developed many pathological conditions similar to those of patients with heterozygous mutations in PKD1. Pathological similarities included the formation of macroscopic renal cysts at the neonatal stage, number and cystogenic dynamics of the renal cysts formed, interstitial fibrosis of the renal tissue, and presence of a premature asymptomatic stage. Our findings demonstrate that PKD1insG/+ pigs recapitulate the characteristic symptoms of ADPKD.

DOI: https://doi.org/10.1038/s41374-021-00717-z
EMBO J. 2022 01 04. 41(1): e108843

Balancing the length of the distal tip by septins is key for stability and signalling function of primary cilia.

Taishi Kanamaru, Annett Neuner, Bahtiyar Kurtulmus, Gislene Pereira.

  Primary cilia are antenna-like organelles required for signalling transduction. How cilia structure is mechanistically maintained at steady-state to promote signalling is largely unknown. Here, we define that mammalian primary cilia axonemes are formed by proximal segment (PS) and distal segment (DS) delineated by tubulin polyglutamylation-rich and -poor regions, respectively. The analysis of proximal/distal segmentation indicated that perturbations leading to cilia over-elongation influenced PS or DS length with a different impact on cilia behaviour. We identified septins as novel repressors of DS growth. We show that septins control the localisation of MKS3 and CEP290 required for a functional transition zone (TZ), and the cilia tip accumulation of the microtubule-capping kinesin KIF7, a cilia-growth inhibitor. Live-cell imaging and analysis of sonic-hedgehog (SHH) signalling activation established that DS over-extension increased cilia ectocytosis events and decreased SHH activation. Our data underlines the importance of understanding cilia segmentation for length control and cilia-dependent signalling.

Keywords:  KIF7; cilia length/segmentation; septins; sonic hedgehog signalling; transition zone

DOI:  https://doi.org/10.15252/embj.2021108843
Front Med (Lausanne). 2021 ;8 743150

Mosaic PKHD1 in Polycystic Kidneys Caused Aberrant Protein Expression in the Mitochondria and Lysosomes.

Chengxian Xu, Chenxi Yang, Qing Ye, Jie Xu, Lingxiao Tong, Yuchen Zhang, Huijun Shen, Zhihong Lu, Jingjing Wang, Enyin Lai, Jianhua Mao, Pingping Jiang.

  Autosomal recessive polycystic kidney disease (ARPKD) is a severe renal cystic disease caused mainly by the polycystic kidney and hepatic disease 1 (PKHD1). However, the genetic cause, pathologic features, and mechanism of action of ARPKD are not well known. Here, we identified a family with ARPKD. Two siblings harbored biallelic variants in PKHD1 (c.7205G>A, c.7973T>A). We determined that the "de novo" variant, c.7205G>A, arose from the mosaicism of the father and had a 7.4% level. Pathologic characterization, using biopsy analysis, was evidenced with predominant cystic dilation in proximal tubules, slight ectasia of collecting ducts, defective ciliogenesis, and impaired cell-cell junctions in renal tubules and collecting ducts. Exosome proteomics in the urine from patients with ARPKD were markedly different from those of controls, with the most significant alterations occurring in mitochondrial and lysosomal proteins. Expression of the proteins of OXPHOS was downregulated sharply, in parallel with upregulated expression of the proteins involved in glycolysis in patients with ARPKD. Several lysosomal proteins associated with renal lesions were more abundant in the exosome of the patient than in controls. Moreover, the lysosomal enzyme sulfamidase, which is produced by the SGSH gene, was abrupt uniquely in the exosome of the patient. Consistently, swollen mitochondria and abundant lysosomes were visualized in the mutant tubular epithelial cells of patients with mutant PKHD1. Collectively, these findings provide new insights on the pathophysiology of the polycystic kidney due to PKHD1 deficiency. PKHD1 mosaicism should be considered in genetic testing of ARPKD patients.

Keywords:  ARPKD; PKHD1; exosome; lysosome; mitochondria; mosaicism

DOI:  https://doi.org/10.3389/fmed.2021.743150
Cardiovasc Drugs Ther. 2022 Jan 08.

Pepducin ICL1-9-Mediated β2-Adrenergic Receptor-Dependent Cardiomyocyte Contractility Occurs in a Gi Protein/ROCK/PKD-Sensitive Manner.

Ama Dedo Okyere, Jianliang Song, Viren Patwa, Rhonda L Carter, Nitya Enjamuri, Anna Maria Lucchese, Jessica Ibetti, Claudio de Lucia, Sarah M Schumacher, Walter J Koch, Joseph Y Cheung, Jeffrey L Benovic, Douglas G Tilley.

   PURPOSE: β-Adrenergic receptors (βAR) are essential targets for the treatment of heart failure (HF); however, chronic use of βAR agonists as positive inotropes to increase contractility in a Gs protein-dependent manner is associated with increased mortality. Alternatively, we previously reported that allosteric modulation of β2AR with the pepducin intracellular loop (ICL)1-9 increased cardiomyocyte contractility in a β-arrestin (βarr)-dependent manner, and subsequently showed that ICL1-9 activates the Ras homolog family member A (RhoA). Here, we aimed to elucidate both the proximal and downstream signaling mediators involved in the promotion of cardiomyocyte contractility in response to ICL1-9.
METHODS: We measured adult mouse cardiomyocyte contractility in response to ICL1-9 or isoproterenol (ISO, as a positive control) alone or in the presence of inhibitors of various potential components of βarr- or RhoA-dependent signaling. We also assessed the contractile effects of ICL1-9 on cardiomyocytes lacking G protein-coupled receptor (GPCR) kinase 2 (GRK2) or 5 (GRK5).
RESULTS: Consistent with RhoA activation by ICL1-9, both Rho-associated protein kinase (ROCK) and protein kinase D (PKD) inhibition were able to attenuate ICL1-9-mediated contractility, as was inhibition of myosin light chain kinase (MLCK). While neither GRK2 nor GRK5 deletion impacted ICL1-9-mediated contractility, pertussis toxin attenuated the response, suggesting that ICL1-9 promotes downstream RhoA-dependent signaling in a Gi protein-dependent manner.
CONCLUSION: Altogether, our study highlights a novel signaling modality that may offer a new approach to the promotion, or preservation, of cardiac contractility during HF via the allosteric regulation of β2AR to promote Gi protein/βarr-dependent activation of RhoA/ROCK/PKD signaling.

Keywords:  G protein; Pepducin; Rho-associated protein kinase; β2-Adrenergic receptor

DOI:  https://doi.org/10.1007/s10557-021-07299-4
Curr Genomics. 2021 Oct 18. 22(3): 232-236

Identification of Two Novel Mutations in PKHD1 Gene from Two Families with Polycystic Kidney Disease by Whole Exome Sequencing.

Masoud Heidari, Hamid Gharshasbi, Alireza Isazadeh, Morteza Soleyman-Nejad, Mohammad Hossein Taskhiri, Javad Shapouri, Manzar Bolhassani, Nahid Sadighi, Mansour Heidari.

   Background: Polycystic kidney disease (PKD) is an autosomal recessive disorder resulting from mutations in the PKHD1 gene on chromosome 6 (6p12), a large gene spanning 470 kb of genomic DNA.
Objective: The aim of the present study was to report newly identified mutations in the PKHD1 gene in two Iranian families with PKD.
Materials and Methods: Genetic alterations of a 3-month-old boy and a 27-year-old girl with PKD were evaluated using whole-exome sequencing. The PCR direct sequencing was performed to analyse the co-segregation of the variants with the disease in the family. Finally, the molecular function of the identified novel mutations was evaluated by in silico study.
Results: In the 3 month-old boy, a novel homozygous frameshift mutation was detected in the PKHD1 gene, which can cause PKD. Moreover, we identified three novel heterozygous missense mutations in ATIC, VPS13B, and TP53RK genes. In the 27-year-old woman, with two recurrent abortions history and two infant mortalities at early weeks due to metabolic and/or renal disease, we detected a novel missense mutation on PKHD1 gene and a novel mutation in ETFDH gene.
Conclusion: In general, we have identified two novel mutations in the PKHD1 gene. These molecular findings can help accurately correlate genotype and phenotype in families with such disease in order to reduce patient births through preoperative genetic diagnosis or better management of disorders.

Keywords:  ETFDH gene; PKHD1 gene; Polycystic kidney disease; disorder; mutation; whole-exome sequencing

DOI:  https://doi.org/10.2174/1389202922666210219111810
Commun Integr Biol. 2021 ;14(1): 264-269

Novel biomarkers of ciliary extracellular vesicles interact with ciliopathy and Alzheimer's associated proteins.

Ashraf M Mohieldin, Amal Alachkar, John Yates, Surya M Nauli.

  Ciliary extracellular vesicles (ciEVs), released from primary cilia, contain functional proteins that play an important role in cilia structure and functions. We have recently shown that ciEVs and cytosolic extracellular vesicles (cyEVs) have unique and distinct biomarkers. While ciEV biomarkers have shown some interactions with known ciliary proteins, little is known about the interaction of ciEV proteins with proteins involved in ciliopathy and neurodegenerative disorders. Here, we reveal for the first time the protein-protein interaction (PPI) between the top five ciEVs biomarkers with ciliopathy and Alzheimer disease (AD) proteins. These results support the growing evidence of the critical physiological roles of cilia in neurodegenerative disorders.

Keywords:  Alzheimer disease; Ciliary extracellular vesicles; bioinformatic; biomarkers; ciliopathy disorders; cytosolic extracellular vesicles; ectosome; exosome; neurodegenerative disorders; primary cilia; proteomics

DOI:  https://doi.org/10.1080/19420889.2021.2017099
Biochim Biophys Acta Mol Basis Dis. 2021 Dec 29. pii: S0925-4439(21)00268-4. [Epub ahead of print] 166335

Deletion of kif3a in CK19 positive cells leads to primary cilia loss, biliary cell proliferation and cystic liver lesions in TAA-treated mice.

Jinbiao Chen, Ngan Ching Cheng, Jade Boland, Ken Liu, James Kench, D Neil Watkins, Sofia Ferreira-Gonzalez, Stuart J Forbes, Geoffrey W McCaughan.

   BACKGROUND & AIMS: Loss of primary cilia in epithelial cells is known to cause cystic diseases of the liver and kidney. We have previously shown that during experimental and human cirrhosis that primary cilia were predominantly expressed on biliary cells in the ductular reaction. However, the role of primary cilia in the pathogenesis of the ductular reaction is not fully understood.
METHODS: Primary cilia were specifically removed in biliary epithelial cells (BECs) by the administration of tamoxifen to Kif3af/f;CK19CreERT mice at week 2 of a 20-week course of TAA treatment. Biliary progenitor cells were isolated and grown as organoids from gallbladders. Cells and tissue were analysed using histology, immunohistochemistry and Western blot assays.
RESULTS: At the end of 20 weeks TAA administration, primary cilia loss in liver BECs resulted in multiple microscopic cystic lesions within an unaltered ductular reaction. These were not seen in control mice who did not receive TAA. There was no effect of biliary primary cilia loss on the development of cirrhosis. Increased cellular proliferation was seen within the cystic structures associated with a decrease in hepatocyte lobular proliferation. Loss of primary cilia within biliary organoids was initially associated with reduced cell passage survival but this inhibitory effect was diminished in later passages. ERK but not WNT signalling was enhanced in primary cilia loss-induced cystic lesions in vivo and its inhibition reduced the expansion of primary cilia deficient biliary progenitor cells in vitro.
CONCLUSIONS: TAA-treated kif3a BEC-specific knockout mice had an unaltered progression to cirrhosis, but developed cystic lesions that showed increased proliferation.

Keywords:  CK19; Cystic lesions; Knockout mice; Organoids; Primary cilia; Progenitor cells; kif3a

DOI:  https://doi.org/10.1016/j.bbadis.2021.166335
Exp Cell Res. 2022 Jan 03. pii: S0014-4827(21)00560-7. [Epub ahead of print]411(2): 113004

Numb inhibits migration and promotes proliferation of colon cancer cells via RhoA/ROCK signaling pathway repression.

Yongtao Yang, Lianyong Li, Huan He, Mengyang Shi, Lanying He, Shuwen Liang, Jun Qi, Weiqing Chen.

  Numb regulates cell proliferation and differentiation through endocytosis and ubiquitination of signaling molecules. Besides, Numb controls the migration of epithelial cells by regulating intercellular junctions. Studies have shown that Numb promotes or inhibits tumor progression in different tumors. However, its role and mechanism in colorectal cancer remain unclear. We found that the expression level of Numb in colon tumor tissues has a great variety in different patients. Numb expression was negatively correlated with TNM stage and lymph node metastasis but positively correlated with tumor size. Elevated expression of Numb was associated with a good prognosis. Inhibiting Numb expression promoted the migration and invasion of colon cancer cells induced by TGF-β, up-regulated the expression of EMT-related molecule Snail, and prevented the expression of E-cadherin. We also found that Numb promoted the proliferation and clones formation while inhibiting colon cancer cells' late apoptosis. In addition, Numb inhibited the RhoA activation and ROCK inhibitor Y-27632 or interfered with ROCK expression, partially inhibiting Numb-regulated cell proliferation and migration. In vivo tumorigenesis assay in nude mice also found that Numb promoted the proliferation of colon cancer cells, inhibited the expression of E-cadherin, and strengthened the expression of Snail. In conclusion, our study found that Numb plays multiple roles in the occurrence and progression of colon cancer by regulating the RhoA/ROCK signaling pathway, which provides a new theoretical molecular basis for the pathogenesis of colon cancer.

Keywords:  Colon cancer; EMT; Numb; Rho-associated protein kinase; RhoA

DOI:  https://doi.org/10.1016/j.yexcr.2021.113004
Structure. 2022 Jan 06. pii: S0969-2126(21)00459-7. [Epub ahead of print]30(1): 4-5

How CEP164 ciliopathy mutations impair ciliogenesis.

Ciaran G Morrison.

CEP164 recruits TTBK2 to the distal end of centrioles to allow primary cilium formation. In this issue of Structure, Rosa e Silva et al. (2022) present co-crystallized structures that show the molecular basis of this recruitment and define how ciliopathy mutations in CEP164 disrupt the CEP164-TTBK2 complex.

DOI: https://doi.org/10.1016/j.str.2021.12.007
Am J Ophthalmol Case Rep. 2022 Mar;25 101245

Rho-Associated Kinase Inhibitor Eye Drops in challenging cataract surgery.

Marco Antonini, Marco Coassin, Daniele Gaudenzi, Antonio Di Zazzo.

   Purpose: To report the impact of Rho-Associated Kinase Inhibitor Eye Drops in cases of cataract surgery performed in severe Fuchs' endothelial corneal dystrophy (FECD).
Observations: A patient affected by FECD stage II underwent femtosecond laser-assisted cataract surgery (FLACS), developed postsurgical corneal failure and was scheduled for endothelial keratoplasty. Compassionate treatment with Rho-Associated Kinase Inhibitor Eye Drops 4 times per day was started. A significant improvement in visual acuity and corneal failure was recorded. Thereafter, other two patients affected by FECD stage II were prophylactically treated with Rho-Associated Kinase Inhibitor Eye Drops 4 times per day for three months before FLACS with good visual and clinical outcome.
Conclusions and Importance: These cases expand upon the reported effects of rho-associated kinase inhibitor Ripasudil in the FECD, suggesting a role as adjuvant medical therapy in patients advised for intraocular surgery to improve endothelial function and reduce the risk of pseudophakic bullous keratopathy (PBK).

Keywords:  Cataract surgery; Corneal edema; Fuchs' dystrophy; Rho inhibitor; Transplantation

DOI:  https://doi.org/10.1016/j.ajoc.2021.101245
Sci Rep. 2022 Jan 07. 12(1): 31

Combinations of deletion and missense variations of the dynein-2 DYNC2LI1 subunit found in skeletal ciliopathies cause ciliary defects.

Hantian Qiu, Yuta Tsurumi, Yohei Katoh, Kazuhisa Nakayama.

Cilia play crucial roles in sensing and transducing extracellular signals. Bidirectional protein trafficking within cilia is mediated by the intraflagellar transport (IFT) machinery containing IFT-A and IFT-B complexes, with the aid of kinesin-2 and dynein-2 motors. The dynein-2 complex drives retrograde trafficking of the IFT machinery after its transportation to the ciliary tip as an IFT cargo. Mutations in genes encoding the dynein-2-specific subunits (DYNC2H1, WDR60, WDR34, DYNC2LI1, and TCTEX1D2) are known to cause skeletal ciliopathies. We here demonstrate that several pathogenic variants of DYNC2LI1 are compromised regarding their ability to interact with DYNC2H1 and WDR60. When expressed in DYNC2LI1-knockout cells, deletion variants of DYNC2LI1 were unable to rescue the ciliary defects of these cells, whereas missense variants, as well as wild-type DYNC2LI1, restored the normal phenotype. DYNC2LI1-knockout cells coexpressing one pathogenic deletion variant together with wild-type DYNC2LI1 demonstrated a normal phenotype. In striking contrast, DYNC2LI1-knockout cells coexpressing the deletion variant in combination with a missense variant, which mimics the situation of cells of compound heterozygous ciliopathy individuals, demonstrated ciliary defects. Thus, DYNC2LI1 deletion variants found in individuals with skeletal ciliopathies cause ciliary defects when combined with a missense variant, which expressed on its own does not cause substantial defects.

DOI: https://doi.org/10.1038/s41598-021-03950-0
J Eukaryot Microbiol. 2022 Jan 07. e12884

Ion Channels of Cilia: Paramecium as a Model.

Megan S Valentine, Judith Van Houten.

  Holotrichous ciliates, like Paramecium, swim through their aqueous environment by beating their many cilia. They can alter swimming speed and direction, which seems to have mesmerized early microscopists of the 1600's. We know from extensive and elegant physiological studies and generation of mutants that these cells can be considered little swimming neurons because their ciliary beating is under bioelectric control of ion channels in the cilia. This chapter will focus on the ionic control of swimming behavior by ciliary ion channels, primarily in the holotrichous ciliate Paramecium. Voltage gated and calcium activated channels for calcium, magnesium, sodium, and potassium are regulated in a closely orchestrated manner that allows cilia to bend and propel the cell forward or backward. Sensory input that generates receptor potentials feeds into the control of this channel activity and allows the cell to turn or speed up. This in turn helps the cell to avoid predators or toxic conditions. While the focus is on P. tetraurelia and P. caudatum, the principles of ciliary ion channel activity and control are easily extendable to other ciliates and protists. The high conservation of channel and ion pump structures also extends the lessons from Paramecium to higher organisms.

Keywords:   Paramecium ; calcium; calmodulin; channelopathy; channels; ciliate; magnesium; potassium

DOI:  https://doi.org/10.1111/jeu.12884
Brain Res Bull. 2022 Jan 03. pii: S0361-9230(21)00369-5. [Epub ahead of print]

Inhibition of ROCK2 kinase activity improved behavioral deficits and reduced neuron damage in a DEACMP rat model.

Linlin Xu, Xuejiao Liu, Chao Guo, Chan Wang, Jing Zhao, Xiaoli Zhang, Wenqiang Li, Ping Zhang, Renjun Gu.

  The main pathological changes that occur in delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) are extensive demyelination of brain white matter and neuron damage. Previous studies suggested that demyelination and neuron injury are related to activating the Rho/ROCK signaling pathway. Inhibition of the Rho/ROCK signaling pathway can alleviate neuron injury and promote myelin repair. This study utilized a DEACMP model in which rats were prepared by space injection of CO gas intraperitoneally (CO group), and the association between the Rho/ROCK signaling pathway and DEACMP was investigated. The ROCK2 kinase inhibitor Y-27632 was used to prevent the effects of the DEACMP model to elucidate its protective mechanism. The results demonstrated that the cognitive and motor functions were significantly impaired, and the GFAP, NSE, RhoA, and ROCK2 protein levels were significantly increased in the CO group within three weeks after the model was established. After Y-27632 intervention, the cognitive and motor functions of the CO+Y-27632 group were significantly improved within three weeks after the model was established. In the CO+Y-27632 group, the RhoA, ROCK2, GFAP, and NSE (indicating neuron injury) protein levels decreased significantly, and the MBP protein levels (indicating myelin repair) increased significantly within three weeks after the model was established. These results suggested that the pathogenesis of DEACMP was associated with activation of the Rho/ROCK pathway and that Y-27632 inhibited ROCK2 kinase activity in the CO exposed rats, resulting in improved behavioral deficits, reduced neuron damage, and promotion of myelin repair. Therefore, Y-27632 might be a potentially effective drug for the treatment of DEACMP-induced brain damage.

Keywords:  Cognitive dysfunction; DEACMP; ROCK2 kinase inhibitors; Rat model; Rho/ROCK signaling pathway

DOI:  https://doi.org/10.1016/j.brainresbull.2021.12.018
Front Biosci (Landmark Ed). 2021 Dec 30. 26(12): 1396-1410

CFTR deficiency aggravates Ang II induced vasoconstriction and hypertension by regulating Ca2+ influx and RhoA/Rock pathway in VSMCs.

Liyan Zhao, Feng Yuan, Ni Pan, Yun Yu, Hanyan Yang, Yaosheng Liu, Ruomei Wang, Bin Zhang, Guanlei Wang.

   BACKGROUND: Cystic fibrosis transmembrane conductance regulator (CFTR) has been associated with vascular tone and blood pressure (BP), however, its role in the genesis of hypertension remains elusive. In the present study, we investigated the regulating effect of CFTR on angiotensin II (Ang II) -induced hypertension and defined the molecular role of CFTR in vasoconstriction.
RESULTS: We found that CFTR mRNA and protein expression were markedly down-regulated in the arteries from Ang II induced hypertensive animals. During the development of hypertension, BP of Cftr-⁣/- mice was significantly higher than that of Cftr+⁣/+ mice. Arteries from Cftr-⁣/- mice or pre-incubated with CFTR specific inhibitor CFTR(inh)-172 exhibited a greater contractile response to Ang II. In vascular smooth muscle cells (VSMCs), the phosphorylation of myosin light chain (MLC), which is the core of VSMCs contraction, was negatively modulated by CFTR. Furthermore, intracellular Ca2+ concentration ([Ca2+]i) rise in response to Ang II was negatively modulated by CFTR, while no alteration was observed in resting VSMCs. Ras homolog family member A/Rho-associated protein kinase (RhoA/Rock) mediated phosphorylation of myosin phosphatase target subunit 1 (MYPT1), a regulator of MLC phosphorylation, was negatively modulated by CFTR in both resting and Ang II-stimulated VSMCs.
CONCLUSIONS: This study demonstrates that CFTR is a negative regulator of vasoconstriction and hypertension, and the underlying mechanism contains two possible pathways: (1) in resting VSMCs, CFTR altered MLC phosphorylation through RhoA/Rock pathway; (2) in Ang II stimulated VSMCs, the regulating effect was mediated by both Ca2+ influx and RhoA/Rock mediated pathway.

Keywords:  CFTR; Ca2+; Hypertension; RhoA; Vascular smooth muscle cells; Vasoconstriction

DOI:  https://doi.org/10.52586/5034
ACS Synth Biol. 2022 Jan 03.

Designing Single-Component Optogenetic Membrane Recruitment Systems: The Rho-Family GTPase Signaling Toolbox.

Erin E Berlew, Keisuke Yamada, Ivan A Kuznetsov, Eleanor A Rand, Chandler C Ochs, Zaynab Jaber, Kevin H Gardner, Brian Y Chow.

  We describe the efficient creation of single-component optogenetic tools for membrane recruitment-based signaling perturbation using BcLOV4 technology. The workflow requires two plasmids to create six different domain arrangements of the dynamic membrane binder BcLOV4, a fluorescent reporter, and the fused signaling protein of interest. Screening of this limited set of genetic constructs for expression characteristics and dynamic translocation in response to one pulse of light is sufficient to identify viable signaling control tools. The reliability of this streamlined approach is demonstrated by the creation of an optogenetic Cdc42 GTPase and Rac1-activating Tiam1 GEF protein, which together with our other recently reported technologies, completes a toolbox for spatiotemporally precise induction of Rho-family GTPase signaling at the GEF or GTPase level, for driving filopodial protrusions, lamellipodial protrusions, and cell contractility, respectively mediated by Cdc42, Rac1, and RhoA.

Keywords:  BcLOV4; Cdc42; Rho GTPase; Tiam1; optogenetics

DOI:  https://doi.org/10.1021/acssynbio.1c00604
FEBS J. 2022 Jan 05.

Nek4 regulates mitochondrial respiration and morphology.

Fernanda Luisa Basei, Camila de Castro Ferezin, Ana Luisa Rodrigues de Oliveira, Juan Pablo Muñoz, Antonio Zorzano, Jörg Kobarg.

  Nek4 is a serine/threonine kinase which has been implicated in primary cilia stabilization, DNA damage response, autophagy and epithelial-to-mesenchymal transition. The role of Nek4 in cancer cell survival and chemotherapy resistance has also been shown. However, the precise mechanisms by which Nek4 operates remain to be elucidated. Here, we show that Nek4 overexpression activates mitochondrial respiration coupled to ATP production, which is paralleled by increased mitochondrial membrane potential, and resistance to mitochondrial DNA damage. Congruently, Nek4 depletion reduced mitochondrial respiration and mtDNA integrity. Nek4 deficiency caused mitochondrial elongation, probably via reduced activity of the fission protein DRP1. In Nek4 overexpressing cells the increase in mitochondrial fission was concomitant to enhanced phosphorylation of DRP1 and Erk1/2 proteins, and the effects on mitochondrial respiration were abolished in the presence of a DRP1 inhibitor. This study shows Nek4 as a novel regulator of mitochondrial function that may explain the joint appearance of high mitochondrial respiration and mitochondrial fragmentation.

Keywords:  DRP1; Nek4; fission; mitochondrial function

DOI:  https://doi.org/10.1111/febs.16343