bims-bicyki Biomed News
on Bicaudal-C1 and interactors in cystic kidney disease
Issue of 2023‒02‒05
eighteen papers selected by
Céline Gagnieux
École Polytechnique Fédérale de Lausanne (EPFL)
  1. Tolvaptan for Autosomal Dominant Polycystic Kidney Disease in Children: Why, Who, and When?
  2. Regional variation in tolvaptan prescribing across England: national data and retrospective evaluation from an expert centre.
  3. A hierarchical pathway for assembly of the distal appendages that organize primary cilia.
  4. Primary cilia-associated protein IFT172 in ciliopathies.
  5. Utility of new image-derived biomarkers for autosomal dominant polycystic kidney disease prognosis using automated instance cyst segmentation.
  6. Tolvaptan for Children and Adolescents with Autosomal Dominant Polycystic Kidney Disease: Randomized Controlled Trial.
  7. Structure-Affinity and Structure-Kinetic Relationship Studies of Benzodiazepine Derivatives for the Development of Efficacious Vasopressin V2 Receptor Antagonists.
  8. Changes in Kidney and Liver Volumes in Patients With Autosomal Dominant Polycystic Kidney Disease Before and After Dialysis Initiation.
  9. Health Disparities in Kidney Failure Among Patients With Autosomal Dominant Polycystic Kidney Disease: A Cross-Sectional Study.
  10. Molecular architecture of the ciliary tip revealed by cryo-electron tomography.
  11. Myristoylated Neuronal Calcium Sensor-1 captures the ciliary vesicle at distal appendages.
  12. Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1.
  13. Global Transcriptomics of Congenital Hepatic Fibrosis in Autosomal Recessive Polycystic Kidney Disease using PCK rats.
  14. The effect of Dnaaf5 gene dosage on primary ciliary dyskinesia phenotypes.
  15. Structure and function of distal and subdistal appendages of the mother centriole.
  16. Editorial: Cell polarity: Trafficking and regulatory events that determine cell asymmetry.
  17. Hyperoxia impairs intraflagellar transport and causes dysregulated metabolism with resultant decreased cilia length.
  18. The non-selective Rho-kinase inhibitors Y-27632 and Y-33075 decrease contraction but increase migration in murine and human hepatic stellate cells.
  1. Clin J Am Soc Nephrol. 2023 Jan 01. 18(1): 11-13
    Tolvaptan for Autosomal Dominant Polycystic Kidney Disease in Children: Why, Who, and When?
    Erum A Hartung.
      
    DOI:  https://doi.org/10.2215/CJN.0000000000000028
  2. Clin Kidney J. 2023 Jan;16(1): 61-68
    Regional variation in tolvaptan prescribing across England: national data and retrospective evaluation from an expert centre.
    Jiehan Chong, Tess Harris, Albert C M Ong.
      Background: Tolvaptan, a vasopressin V2 receptor antagonist, was approved in 2015 by the UK National Institute for Health and Care Excellence for use in patients with autosomal dominant polycystic kidney disease (ADPKD) and rapid disease progression. Simultaneous guidance was issued by the UK Kidney Association (UKKA) to facilitate national implementation.Methods: Data on tolvaptan prescribing in England was obtained through the National Health Service (NHS) Digital, a national survey of all 77 adult kidney units, and the implementation of UKKA guidance was evaluated at an expert PKD centre.
    Results: A regional variation of up to 4-fold for tolvaptan prescribing in England was found. Despite most kidney units following UKKA guidance, centre-based estimates of eligible or treated patient numbers were highly variable. Retrospective evaluation at an expert PKD centre revealed that in a cohort demonstrating rapid estimated glomerular filtration rate (eGFR) decline, 14% would not be eligible for tolvaptan by Mayo imaging classification and more than half (57%) would not be eligible by Predicting Renal Outcome in Polycystic Kidney Disease score. The 3-year discontinuation rate was higher than expected (56%), the majority (70%) due to aquaretic symptoms. In patients taking tolvaptan for at least 2 years, 81% showed a reduction in the rate of eGFR decline compared with baseline, with earlier disease associated with positive treatment response.
    Conclusion: Real-world data have revealed a much higher regional variation in tolvaptan prescribing for ADPKD in England than expected. We propose further investigation into the factors responsible for this variation.
    Keywords:  PKD1; PKD2; autosomal dominant polycystic kidney disease; patient selection; prognostic risk assessment; tolvaptan; total kidney volume
    DOI:  https://doi.org/10.1093/ckj/sfac190
  3. bioRxiv. 2023 Jan 10. pii: 2023.01.06.522944. [Epub ahead of print]
    A hierarchical pathway for assembly of the distal appendages that organize primary cilia.
    Tomoharu Kanie, Julia F Love, Saxton D Fisher, Anna-Karin Gustavsson, Peter K Jackson.
      Distal appendages are nine-fold symmetric blade-like structures attached to the distal end of the mother centriole. These structures are critical for formation of the primary cilium, by regulating at least four critical steps: ciliary vesicle recruitment, recruitment and initiation of intraflagellar transport (IFT), and removal of CP110. While specific proteins that localize to the distal appendages have been identified, how exactly each protein functions to achieve the multiple roles of the distal appendages is poorly understood. Here we comprehensively analyze known and newly discovered distal appendage proteins (CEP83, SCLT1, CEP164, TTBK2, FBF1, CEP89, KIZ, ANKRD26, PIDD1, LRRC45, NCS1, C3ORF14) for their precise localization, order of recruitment, and their roles in each step of cilia formation. Using CRISPR-Cas9 knockouts, we show that the order of the recruitment of the distal appendage proteins is highly interconnected and a more complex hierarchy. Our analysis highlights two protein modules, CEP83-SCLT1 and CEP164-TTBK2, as critical for structural assembly of distal appendages. Functional assay revealed that CEP89 selectively functions in RAB34 + ciliary vesicle recruitment, while deletion of the integral components, CEP83-SCLT1-CEP164-TTBK2, severely compromised all four steps of cilium formation. Collectively, our analyses provide a more comprehensive view of the organization and the function of the distal appendage, paving the way for molecular understanding of ciliary assembly.
    DOI:  https://doi.org/10.1101/2023.01.06.522944
  4. Front Cell Dev Biol. 2023 ;11 1074880
    Primary cilia-associated protein IFT172 in ciliopathies.
    Nan-Xi Zheng, Ya-Ting Miao, Xi Zhang, Mu-Zhi Huang, Muhammad Jahangir, Shilin Luo, Bing Lang.
      Cilium is a highly conserved antenna-like structure protruding from the surface of the cell membrane, which is widely distributed on most mammalian cells. Two types of cilia have been described so far which include motile cilia and immotile cilia and the latter are also known as primary cilia. Dysfunctional primary cilia are commonly associated with a variety of congenital diseases called ciliopathies with multifaceted presentations such as retinopathy, congenital kidney disease, intellectual disability, cancer, polycystic kidney, obesity, Bardet Biedl syndrome (BBS), etc. Intraflagellar transport (IFT) is a bi-directional transportation process that helps maintain a balanced flow of proteins or signaling molecules essential for the communication between cilia and cytoplasm. Disrupted IFT contributes to the abnormal structure or function of cilia and frequently promotes the occurrence of ciliopathies. Intraflagellar transport 172 (IFT172) is a newly identified member of IFT proteins closely involved in some rare ciliopathies such as Mainzer-Saldino syndrome (MZSDS) and BBS, though the underpinning causal mechanisms remain largely elusive. In this review, we summarize the key findings on the genetic and protein characteristic of IFT172, as well as its function in intraflagellar transport, to provide comprehensive insights to understand IFT172-related ciliopathies.
    Keywords:  IFT172; bardet biedl syndrome; ciliopathy; intraflagellar transport; primary cilia
    DOI:  https://doi.org/10.3389/fcell.2023.1074880
  5. Kidney Int. 2023 Jan 31. pii: S0085-2538(23)00058-3. [Epub ahead of print]
    Utility of new image-derived biomarkers for autosomal dominant polycystic kidney disease prognosis using automated instance cyst segmentation.
    Adriana V Gregory, Fouad Chebib, Bhavya Poudyal, Heather Holmes, Alan S L Yu, Douglas P Landsittel, Kyongtae T Bae, Arlene B Chapman, Rahbari-Oskoui Frederic, Michal Mrug, William M Bennett, Peter C Harris, Bradley J Erickson, Vicente E Torres, Timothy L Kline.
      New image-derived biomarkers for patients affected by autosomal dominant polycystic kidney disease are needed to improve current clinical management. The measurement of total kidney volume (TKV) provides critical information for clinicians to drive care decisions. However, patients with similar TKV may present with very different phenotypes, often requiring subjective decisions based on other factors (e.g., appearance of healthy kidney parenchyma, a few cysts contributing significantly to overall TKV, etc.). In this study, we describe a new technique to individually segment cysts and quantify biometric parameters including cyst volume, cyst number, parenchyma volume, and cyst parenchyma surface area. Using data from the Consortium for Radiologic Imaging Studies of Polycystic Kidney Disease (CRISP) study the utility of these new parameters was explored, both quantitatively as well as visually. Total cyst number and cyst parenchyma surface area showed superior prediction of the slope of estimated glomerular filtration rate decline, kidney failure and chronic kidney disease stages 3A, 3B, and 4, compared to TKV. In addition, presentations such as a few large cysts contributing significantly to overall kidney volume were shown to be much better stratified in terms of outcome predictions. Thus, these new image biomarkers, which can be obtained automatically, will have great utility in future studies and clinical care for patients affected by autosomal dominant polycystic kidney disease.
    Keywords:  Polycystic kidney disease; disease prognosis; glomerular filtration rate; imaging biomarkers; instance segmentation; outcome prediction
    DOI:  https://doi.org/10.1016/j.kint.2023.01.010
  6. Clin J Am Soc Nephrol. 2023 Jan 01. 18(1): 36-46
    Tolvaptan for Children and Adolescents with Autosomal Dominant Polycystic Kidney Disease: Randomized Controlled Trial.
    Djalila Mekahli, Lisa M Guay-Woodford, Melissa A Cadnapaphornchai, Larry A Greenbaum, Mieczyslaw Litwin, Tomas Seeman, Ann Dandurand, Lily Shi, Kimberly Sikes, Susan E Shoaf, Franz Schaefer.
      BACKGROUND: Tolvaptan slows expansion of kidney volume and kidney function decline in adults with autosomal dominant polycystic kidney disease (ADPKD). Progression during childhood could be treated before irreversible kidney damage occurs, but trial data are lacking. We evaluated the safety and efficacy of tolvaptan in children/adolescents with ADPKD.METHODS: This was the 1-year, randomized, double-blind, portion of a phase 3b, two-part trial being conducted at 20 academic pediatric nephrology centers. Key eligibility criteria were ADPKD and eGFR ≥60 ml/min per 1.73 m2. Participants aged 12-17 years were the target group (group 1, enrollment goal n≥60); participants aged 4-11 years could additionally enroll (group 2, anticipated enrollment approximately 40). Treatments were tolvaptan or placebo titrated by body weight and tolerability. Coprimary end points, change from baseline in spot urine osmolality and specific gravity at week 1, assessed inhibition of antidiuretic hormone activity. The key secondary end point was change in height-adjusted total kidney volume (htTKV) to month 12 in group 1. Additional end points were safety/tolerability and quality of life. Statistical comparisons were exploratory and post hoc.
    RESULTS: Among the 91 randomized (group 1, n=66; group 2, n=25), least squares (LS) mean reduction (±SEM) in spot urine osmolality at week 1 was greater with tolvaptan (-390 [28] mOsm/kg) than placebo (-90 [29] mOsm/kg; P<0.001), as was LS mean reduction in specific gravity (-0.009 [0.001] versus -0.002 [0.001]; P<0.001). In group 1, the 12-month htTKV increase was 2.6% with tolvaptan and 5.8% with placebo (P>0.05). For tolvaptan and placebo, respectively, 65% and 16% of subjects experienced aquaretic adverse events, and 2% and 0% experienced hypernatremia. There were no elevated transaminases or drug-induced liver injuries. Four participants discontinued tolvaptan, and three discontinued placebo. Quality-of-life assessments remained stable.
    CONCLUSIONS: Tolvaptan exhibited pharmacodynamic activity in pediatric ADPKD. Aquaretic effects were manageable, with few discontinuations.
    CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: Safety, Pharmacokinetics, Tolerability and Efficacy of Tolvaptan in Children and Adolescents With ADPKD (Autosomal Dominant Polycystic Kidney Disease) NCT02964273.
    DOI:  https://doi.org/10.2215/CJN.0000000000000022
  7. J Med Chem. 2023 Feb 02.
    Structure-Affinity and Structure-Kinetic Relationship Studies of Benzodiazepine Derivatives for the Development of Efficacious Vasopressin V2 Receptor Antagonists.
    Xudong Cao, Peng Wang, Wenchao Zhao, Haoxing Yuan, Hongtao Hu, Ting Chen, Yixiao Zhang, Ying Ren, Limin Su, Kequan Fu, Hongli Liu, Dong Guo.
      Vasopressin V2 receptors (V2R) are a promising drug target for autosomal dominant polycystic kidney disease (ADPKD). As previous research demonstrated that the residence time of V2R antagonists is critical to their efficacy in both ex vivo and in vivo models of ADPKD, we performed extensive structure-kinetic relationship (SKR) analyses on a series of benzodiazepine derivatives. We found that subtle structural modifications of the benzodiazepine derivatives dramatically changed their binding kinetics but not their affinity. Compound 18 exhibited a residence time of 77 min, which was 7.7-fold longer than that of the reference compound tolvaptan (TVP). Accordingly, compound 18 exhibited higher efficacy compared to TVP in an in vivo model of ADPKD. Overall, our study exemplifies a kinetics-directed medicinal chemistry effort for the development of efficacious V2R antagonists. We envision that this strategy may also have general applicability in other therapeutic areas.
    DOI:  https://doi.org/10.1021/acs.jmedchem.3c00015
  8. Mayo Clin Proc Innov Qual Outcomes. 2023 Feb;7(1): 69-80
    Changes in Kidney and Liver Volumes in Patients With Autosomal Dominant Polycystic Kidney Disease Before and After Dialysis Initiation.
    Tatsuya Suwabe, Yoshifumi Ubara, Yuki Oba, Hiroki Mizuno, Daisuke Ikuma, Masayuki Yamanouchi, Akinari Sekine, Kiho Tanaka, Eiko Hasegawa, Junichi Hoshino, Naoki Sawa.
      Objective: To examine the changes in total kidney volume (TKV) and total liver volume (TLV) before and after dialysis initiation in patients with autosomal dominant polycystic kidney disease.Patients and Methods: This was a retrospective, single-center cohort study to investigate the changes in TKV and TLV before and after dialysis initiation, along with influencing factors, using linear mixed models. We enrolled 95 patients with autosomal dominant polycystic kidney disease (85 receiving hemodialysis [HD] and 10 receiving peritoneal dialysis [PD]) who began receiving dialysis at Toranomon Hospital from January 1, 2008, to December 31, 2020.
    Results: The least squares mean TKV ratio (TKV at each time point/TKV at dialysis initiation) was 63.8% (95% confidence interval [CI], 54.7%-72.9%) at 6 years before dialysis initiation and 95.5% (95% CI, 82.9%-108.2%) at 6 years after dialysis initiation (P<.001). A multivariate linear mixed model analysis revealed that dialysis style (HD or PD) had the strongest effect on changes in TKV (P=.002). The least squares mean TLV ratio was 98.2% (95% CI, 88.4%-108.0%) at 6 years before dialysis initiation and 95.7% (95% CI, 85.2%-106.2%) at 6 years after dialysis initiation (P=.01). Although PD did not have significant effects on changes in TLV (P=.27), the changes in TLV were greater in patients on PD than in those on HD.
    Conclusion: The TKV increased until dialysis initiation and generally decreased after dialysis initiation. The TLV continued to increase even after dialysis initiation, however, changes in the TLV significantly decreased after dialysis initiation. The increases in TKV and TLV were greater in patients on PD than in those on HD.
    Keywords:  ACDK, acquired cystic disease of the kidney; ADPKD, autosomal dominant polycystic kidney disease; ALB, albumin; BMI, body mass index; BP, blood pressure; CI, confidence interval; CT, computed tomography; ESKD, end-stage kidney disease; HD, hemodialysis; HR, heart rate; MRI, magnetic resonance imaging; PD, peritoneal dialysis; PKD, polycystic kidney disease; PLD, polycystic liver disease; TAE, transcatheter arterial embolization; TKV, total kidney volume; TLV, total liver volume; UN, urea nitrogen; eGFR, estimated glomerular filtration rate
    DOI:  https://doi.org/10.1016/j.mayocpiqo.2022.12.005
  9. Kidney Med. 2023 Feb;5(2): 100577
    Health Disparities in Kidney Failure Among Patients With Autosomal Dominant Polycystic Kidney Disease: A Cross-Sectional Study.
    Teresa N Harrison, Qiaoling Chen, Min Young Lee, Mercedes A Munis, Kerresa Morrissette, Shirin Sundar, Kristin Pareja, Ali Nourbakhsh, Yu-Hsiang Shu, Cynthia J Willey, John J Sim.
      Rationale & Objective: Understanding potential differences in patterns of kidney failure among patients with autosomal dominant polycystic kidney disease (ADPKD) may provide insights into improving disease management. We sought to characterize patients with ADPKD and kidney failure across different race/ethnicities.Study Design: Cross-sectional study.
    Setting & Participants: Kaiser Permanente Southern California members diagnosed with ADPKD between January1, 2002, and December 31, 2018.
    Exposure: ADPKD.
    Outcome: Kidney failure, dialysis, or receipt of kidney transplant.
    Analytical Approach: Differences in characteristics by race/ethnicity were assessed using analysis of variance F test and χ2 test. To compare the range and distribution of the average age at onset of kidney failure by race/ethnicity and sex, we used box plots and confidence intervals. Multivariable logistic regression was used to estimate OR for kidney transplant.
    Results: Among 3,677 ADPKD patients, 1,027 (27.3%) had kidney failure. The kidney failure cohort was comprised of Black (n=138; 30.7%), White (n=496; 30.6%), Hispanic (n=306; 24.7%), and Asian (n=87; 23.6%) patients. Hispanic patients had the youngest mean age of kidney failure onset (50 years) compared to Black (56 years) and White (57 years) patients. Black (44.2%; OR, 0.72) and Hispanic (49.7%; OR, 0.65) patients had lower rates of kidney transplantation compared to White (53.8%) patients. Preemptive kidney transplantations occurred in 15.0% of patients.
    Limitations: Retrospective study design and possible misclassification of ADPKD cases. Kidney function calculations were based on equations incorporating race, potentially overestimating kidney function in African Americans. The study was conducted within a single, integrated health care system in 1 geographic region and may not be generalizable to all ADPKD patients.
    Conclusions: Among a large diverse ADPKD population, we observed racial/ethnic differences in rates of kidney failure, age of kidney failure onset, and rates of kidney transplantation. Our real-world ADPKD cohort provides insight into racial/ethnic variation in clinical features of disease and potential disparities in care, which may affect ADPKD outcomes.
    DOI:  https://doi.org/10.1016/j.xkme.2022.100577
  10. bioRxiv. 2023 Jan 03. pii: 2023.01.03.522627. [Epub ahead of print]
    Molecular architecture of the ciliary tip revealed by cryo-electron tomography.
    T Legal, M Tong, C Black, M Valente Paterno, J Gaertig, K H Bui.
      Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila . We show the microtubules in the tip are highly cross-linked with each other and stabilised by luminal proteins, plugs and cap proteins at the plus ends. In the tip region, the central pair lacks the typical projections and twists significantly. By analysing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explain potential functions of CEP104/FAP256 . These data provide new insights into the function of the ciliary tip and inform about the mechanisms of ciliary assembly and length regulation.
    DOI:  https://doi.org/10.1101/2023.01.03.522627
  11. bioRxiv. 2023 Jan 10. pii: 2023.01.06.523037. [Epub ahead of print]
    Myristoylated Neuronal Calcium Sensor-1 captures the ciliary vesicle at distal appendages.
    Tomoharu Kanie, Roy Ng, Keene L Abbott, Olaf Pongs, Peter K Jackson.
      The primary cilium is a microtubule-based organelle that cycles through assembly and disassembly. In many cell types, formation of the cilium is initiated by recruitment of ciliary vesicles to the distal appendage of the mother centriole. However, the distal appendage mechanism that directly captures ciliary vesicles is yet to be identified. In an accompanying paper, we show that the distal appendage protein, CEP89, is important for thef ciliary vesicle recruitment, but not for other steps of cilium formation (Tomoharu Kanie, Love, Fisher, Gustavsson, & Jackson, 2023). The lack of a membrane binding motif in CEP89 suggests that it may indirectly recruit ciliary vesicles via another binding partner. Here, we identify Neuronal Calcium Sensor-1 (NCS1) as a stoichiometric interactor of CEP89. NCS1 localizes to the position between CEP89 and a ciliary vesicle marker, RAB34, at the distal appendage. This localization was completely abolished in CEP89 knockouts, suggesting that CEP89 recruits NCS1 to the distal appendage. Similarly to CEP89 knockouts, ciliary vesicle recruitment as well as subsequent cilium formation was perturbed in NCS1 knockout cells. The ability of NCS1 to recruit the ciliary vesicle is dependent on its myristoylation motif and NCS1 knockout cells expressing myristoylation defective mutant failed to rescue the vesicle recruitment defect despite localizing proper localization to the centriole. In sum, our analysis reveals the first known mechanism for how the distal appendage recruits the ciliary vesicles.
    DOI:  https://doi.org/10.1101/2023.01.06.523037
  12. Front Mol Biosci. 2022 ;9 946344
    Transcription factor Ap2b regulates the mouse autosomal recessive polycystic kidney disease genes, Pkhd1 and Cys1.
    Maoqing Wu, Naoe Harafuji, Amber K O'Connor, Ljubica Caldovic, Lisa M Guay-Woodford.
      Transcription factor Ap2b (TFAP2B), an AP-2 family transcription factor, binds to the palindromic consensus DNA sequence, 5'-GCCN3-5GGC-3'. Mice lacking functional Tfap2b gene die in the perinatal or neonatal period with cystic dilatation of the kidney distal tubules and collecting ducts, a phenotype resembling autosomal recessive polycystic kidney disease (ARPKD). Human ARPKD is caused by mutations in PKHD1, DZIP1L, and CYS1, which are conserved in mammals. In this study, we examined the potential role of TFAP2B as a common regulator of Pkhd1 and Cys1. We determined the transcription start site (TSS) of Cys1 using 5' Rapid Amplification of cDNA Ends (5'RACE); the TSS of Pkhd1 has been previously established. Bioinformatic approaches identified cis-regulatory elements, including two TFAP2B consensus binding sites, in the upstream regulatory regions of both Pkhd1 and Cys1. Based on reporter gene assays performed in mouse renal collecting duct cells (mIMCD-3), TFAP2B activated the Pkhd1 and Cys1 promoters and electromobility shift assay (EMSA) confirmed TFAP2B binding to the in silico identified sites. These results suggest that Tfap2b participates in a renal epithelial cell gene regulatory network that includes Pkhd1 and Cys1. Disruption of this network impairs renal tubular differentiation, causing ductal dilatation that is the hallmark of recessive PKD.
    Keywords:  Cys1; Pkhd1; TFAP2B; Tfap2b; autosomal recessive polycystic kidney disease (ARPKD)
    DOI:  https://doi.org/10.3389/fmolb.2022.946344
  13. bioRxiv. 2023 Jan 20. pii: 2023.01.19.524760. [Epub ahead of print]
    Global Transcriptomics of Congenital Hepatic Fibrosis in Autosomal Recessive Polycystic Kidney Disease using PCK rats.
    Satyajeet Khare, Lu Jiang, Diego Paine Cabrara, Udayan Apte, Michele T Pritchard.
      Congenital hepatic fibrosis / Autosomal recessive polycystic kidney disease (CHF/ARPKD) is an inherited neonatal disease induced by mutations in the PKHD1 gene and characterized by cysts, and robust pericystic fibrosis in liver and kidney. The PCK rat is an excellent animal model which carries a Pkhd1 mutation and exhibits similar pathophysiology. We performed RNA-Seq analysis on liver samples from PCK rats over a time course of postnatal day (PND) 15, 20, 30, and 90 using age-matched Sprague-Dawley (SD) rats as controls to characterize molecular mechanisms of CHF/ARPKD pathogenesis. A comprehensive differential gene expression (DEG) analysis identified 1298 DEGs between PCK and SD rats. The genes overexpressed in the PCK rats at PND 30 and 90 were involved cell migration (e.g. Lamc2, Tgfb2 , and Plet1 ), cell adhesion (e.g. Spp1, Adgrg1 , and Cd44 ), and wound healing (e.g. Plat, Celsr1, Tpm1 ). Connective tissue growth factor ( Ctgf ) and platelet-derived growth factor ( Pdgfb ), two genes associated with fibrosis, were upregulated in PCK rats at all time-points. Genes associated with MHC class I molecules (e.g. RT1-A2 ) or involved in ribosome assembly (e.g. Pes1 ) were significantly downregulated in PCK rats. Upstream regulator analysis showed activation of proteins involved tissue growth (MTPN) and inflammation (STAT family members) and chromatin remodeling (BRG1), and inhibition of proteins involved in hepatic differentiation (HNF4α) and reduction of fibrosis (SMAD7). The increase in mRNAs of four top upregulated genes including Reg3b, Aoc1, Tm4sf20 , and Cdx2 was confirmed at the protein level using immunohistochemistry. In conclusion, these studies indicate that a combination of increased inflammation, cell migration and wound healing, and inhibition of hepatic function, decreased antifibrotic gene expression are the major underlying pathogenic mechanisms in CHF/ARPKD.
    DOI:  https://doi.org/10.1101/2023.01.19.524760
  14. bioRxiv. 2023 Jan 14. pii: 2023.01.13.523966. [Epub ahead of print]
    The effect of Dnaaf5 gene dosage on primary ciliary dyskinesia phenotypes.
    Amjad Horani, Deepesh Kumar Gupta, Jian Xu, Huihui Xu, Lis Del Carmen Puga-Molina, Celia M Santi, Sruthi Ramagiri, Steven K Brennen, Jiehong Pan, Tao Huang, Rachael M Hyland, Sean P Gunsten, Shin-Cheng Tzeng, Jennifer M Strahle, Pleasantine Mill, Moe R Mahjoub, Susan K Dutcher, Steven L Brody.
      DNAAF5 is a dynein motor assembly factor associated with the autosomal heterogenic recessive condition of motile cilia, primary ciliary dyskinesia (PCD). The effects of allele heterozygosity on motile cilia function are unknown. We used CRISPR-Cas9 genome editing in mice to recreate a human missense variant identified in patients with mild PCD and a second, frameshift null deletion in Dnaaf5 . Litters with Dnaaf5 heteroallelic variants showed distinct missense and null gene dosage effects. Homozygosity for the null Dnaaf5 alleles was embryonic lethal. Compound heterozygous animals with the missense and null alleles showed severe disease manifesting as hydrocephalus and early lethality. However, animals homozygous for the missense mutation had improved survival, with partial preserved cilia function and motor assembly observed by ultrastructure analysis. Notably, the same variant alleles exhibited divergent cilia function across different multiciliated tissues. Proteomic analysis of isolated airway cilia from mutant mice revealed reduction in some axonemal regulatory and structural proteins not previously reported in DNAAF5 variants. While transcriptional analysis of mouse and human mutant cells showed increased expression of genes coding for axonemal proteins. Together, these findings suggest allele-specific and tissue-specific molecular requirements for cilia motor assembly that may affect disease phenotypes and clinical trajectory in motile ciliopathies.Brief Summary: A mouse model of human DNAAF5 primary ciliary dyskinesia variants reveals gene dosage effects of mutant alleles and tissue-specific molecular requirements for cilia motor assembly.
    DOI:  https://doi.org/10.1101/2023.01.13.523966
  15. J Cell Sci. 2023 Feb 01. pii: jcs260560. [Epub ahead of print]136(3):
    Structure and function of distal and subdistal appendages of the mother centriole.
    Dandan Ma, Fulin Wang, Junlin Teng, Ning Huang, Jianguo Chen.
      Centrosomes are composed of centrioles surrounded by pericentriolar material. The two centrioles in G1 phase are distinguished by the localization of their appendages in the distal and subdistal regions; the centriole possessing both types of appendage is older and referred to as the mother centriole, whereas the other centriole lacking appendages is the daughter centriole. Both distal and subdistal appendages in vertebrate cells consist of multiple proteins assembled in a hierarchical manner. Distal appendages function mainly in the initial process of ciliogenesis, and subdistal appendages are involved in microtubule anchoring, mitotic spindle regulation and maintenance of ciliary signaling. Mutations in genes encoding components of both appendage types are implicated in ciliopathies and developmental defects. In this Review, we discuss recent advances in knowledge regarding the composition and assembly of centriolar appendages, as well as their roles in development and disease.
    Keywords:  Centrosome; Ciliogenesis; Distal appendages; Microtubule anchoring; Subdistal appendages
    DOI:  https://doi.org/10.1242/jcs.260560
  16. Front Cell Dev Biol. 2023 ;11 1119485
    Editorial: Cell polarity: Trafficking and regulatory events that determine cell asymmetry.
    Andrés E Zucchetti, James R Goldenring, M Cecilia Larocca.
      
    Keywords:  cofilin; epithelial polarity; neuronal polarity; phosphoinositides; primary cilia; sonic hedgehog
    DOI:  https://doi.org/10.3389/fcell.2023.1119485
  17. Am J Physiol Lung Cell Mol Physiol. 2023 Jan 31.
    Hyperoxia impairs intraflagellar transport and causes dysregulated metabolism with resultant decreased cilia length.
    Daniella Teape, Abigail Peterson, Nagib Ahsan, Kimberlyn Ellis, Nicholas Correia, Ryan Luo, Katy Hegarty, Hongwei Yao, Phyllis Dennery.
      Supplemental oxygen is a lifesaving measure in infants born premature to facilitate oxygenation that may lead to alveolar simplification and loss of proximal airway epithelial cilia. Little is known about the mechanism of hyperoxic ciliary dysfunction in the proximal respiratory tract. We hypothesized that hyperoxia causes intraflagellar transport (IFT) dysfunction with resultant decreased cilia length. Differentiated basal human airway epithelial cells (HAEC) were exposed to hyperoxia or air for up to 48 h. Neonatal mice (<12 h old) were exposed to hyperoxia for 72 h and recovered in air until postnatal day (PND) 60. Cilia length was measured from scanning electron microscopy images using a MATLAB derived program. Proteomics and metabolomics were carried out in cells after hyperoxia. There was a significant time-dependent reduction in cilia length after hyperoxia in HAEC. Proteomic analysis showed decreased abundance of multiple proteins related to IFT including dynein motor proteins after hyperoxia. In neonatal mice exposed to hyperoxia, there was a significant decrease in acetylated α tubulin at PND10 with recovery to normal levels at PND60. In HAEC, abundance of multiple proteins associated with complex I of the electron transport chain were decreased by hyperoxia. Additionally, in HAEC, hyperoxia increased levels of malate, fumarate, and citrate, and reduced the ATP/ADP ratio at 24 h with a subsequent increase at 36 h. Exposure to hyperoxia reduces cilia length, which is associated with aberrant IFT protein expression and dysregulated metabolism. This delineates potential aberrant IFT protein expression upon hyperoxic exposure on the respiratory epithelium.
    Keywords:  bronchopulmonary dysplasia; cilia; comparative proteomics; intraflagellar transport
    DOI:  https://doi.org/10.1152/ajplung.00522.2021
  18. PLoS One. 2023 ;18(1): e0270288
    The non-selective Rho-kinase inhibitors Y-27632 and Y-33075 decrease contraction but increase migration in murine and human hepatic stellate cells.
    Nadine Bachtler, Sandra Torres, Cristina Ortiz, Robert Schierwagen, Olaf Tyc, Christoph Hieber, Marie-Luise Berres, Caroline Meier, Nico Kraus, Stefan Zeuzem, Bart Nijmeijer, Sebas Pronk, Jonel Trebicka, Sabine Klein.
      BACKGROUND: The Rho-kinase ROCK II plays a major role in the activation of hepatic stellate cells (HSC), which are the key profibrotic and contractile cells contributing to the development of chronic liver disease. Inhibition of ROCK II ultimately blocks the phosphorylation of the myosin light chain (MLC) and thus inhibits stress fibre assembly and cell contraction. We investigated the effects of the ROCK inhibitors Y-33075 as well as Y-27632 in murine and human hepatic stellate cells.METHODS: Primary isolated HSC from FVB/NJ mice and the immortalized human HSC line TWNT-4 were culture-activated and incubated with Y-27632 and Y-33075 (10nM to 10μM) for 24h. Protein expression levels were analyzed by Western Blots and transcriptional levels of pro-fibrotic markers and proliferative markers were evaluated using real-time qPCR. Migration was investigated by wound-healing assay. Proliferation was assessed by BrdU assay. Contraction of HSC was measured using 3D collagen matrices after incubation with Y-27632 or Y-33075 in different doses.
    RESULTS: Both Rho-kinase inhibitors, Y-27632 and Y-33075, reduced contraction, fibrogenesis and proliferation in activated primary mouse HSC (FVB/NJ) and human HSC line (TWNT-4) significantly. Y-33075 demonstrated a 10-times increased potency compared to Y-27632. Surprisingly, both inhibitors mediated a substantial and unexpected increase in migration of HSC in FVB/NJ.
    CONCLUSION: ROCK inhibition by the tested compounds decreased contraction but increased migration. Y-33075 proved more potent than Y27632 in the inhibition of contraction of HSCs and should be further evaluated in chronic liver disease.
    DOI:  https://doi.org/10.1371/journal.pone.0270288
This page is being maintained by Thomas Krichel. It was last updated on 2023‒02‒14 at 10:40:01.