bims-bicyki 2022-10-30 papers

bims-bicyki

Biomed News

on Bicaudal-C1 and interactors in cystic kidney disease

Issue of 2022‒10‒30
twenty-two papers selected by
Céline Gagnieux
École Polytechnique Fédérale de Lausanne (EPFL)

Kidney Cyst Lining Epithelial Cells Are Resistant to Low-Dose Cisplatin-Induced DNA Damage in a Preclinical Model of Autosomal Dominant Polycystic Kidney Disease.
Myofibroblast depletion reduces kidney cyst growth and fibrosis in autosomal dominant polycystic kidney disease.
PKD1 mosaicism associated with severe renal, hepatic, and vascular phenotype.
Predicting Progression of Autosomal Dominant Polycystic Kidney Disease by Changes in the Telomeric Epigenome.
Evaluation of the relationship between the mean platelet volume and the neutrophil/lymphocyte ratio with progression of chronic kidney disease in patients with autosomal dominant polycystic kidney disease.
Echocardiographic Abnormalities in Autosomal Dominant Polycystic Kidney Disease (ADPKD) Patients.
Enhancer and super-enhancer landscape in polycystic kidney disease.
Involvement of ceramide biosynthesis in increased extracellular vesicle release in Pkd1 knock out cells.
Impact of kidney function and kidney volume on intracranial aneurysms in patients with autosomal dominant polycystic kidney disease.
Visual inspection reveals a novel pathogenic mutation in PKD1 missed by the variant caller in whole‑exome sequencing.
Adult human kidney organoids originate from CD24+ cells and represent an advanced model for adult polycystic kidney disease.
PDGF-AA activates AKT and ERK signaling for testicular interstitial Leydig cell growth via primary cilia.
Kinesin-2 motors differentially impact biogenesis of extracellular vesicle subpopulations shed from sensory cilia.
A ccpp-6 deletion mutation does not impair gross cilia integrity in C. elegans.
Management of Renal Angiomyolipomas in Tuberous Sclerosis Complex: A Case Report and Literature Review.
Identification of a novel founder variant in DNAI2 cause primary ciliary dyskinesia in five consanguineous families derived from a single tribe descendant of Arabian Peninsula.
Biallelic variants in CEP164 cause a motile ciliopathy-like syndrome.
Basal bodies bend in response to ciliary forces.
Loss of primary cilia promotes inflammation and carcinogenesis.
IFT20: An Eclectic Regulator of Cellular Processes beyond Intraflagellar Transport.
Hypertension is Linked to Enhanced Lymphatic Contractile Response via RGS16/RhoA/ROCK Pathway.
Predicting the locations of force-generating dyneins in beating cilia and flagella.

Int J Mol Sci. 2022 Oct 19. pii: 12547. [Epub ahead of print]23(20):

Kidney Cyst Lining Epithelial Cells Are Resistant to Low-Dose Cisplatin-Induced DNA Damage in a Preclinical Model of Autosomal Dominant Polycystic Kidney Disease.

Sayanthooran Saravanabavan, Gopala K Rangan.

  Increased DNA damage response (DDR) signaling in kidney cyst-lining epithelial cells (CECs) may provide an opportunity for cell-specific therapeutic targeting in autosomal dominant polycystic kidney disease (ADPKD). We hypothesized that inhibiting ataxia telangiectasia mutated (ATM; a proximal DDR kinase) together with low-dose cisplatin overwhelms the DDR response and leads to selective apoptosis of cyst-lining epithelial cells (CECs). Pkd1RC/RC/Atm+/- mice were treated with either vehicle or a single low-dose cisplatin, and the acute effects on CECs (DNA damage and apoptosis) after 72 h and chronic effects on progression (cyst size, inflammation, fibrosis) after 3 weeks were investigated. At 72 h, cisplatin caused a dose-dependent increase in γH2AX-positive nuclei in both CECs and non-cystic tubules but did not cause selective apoptosis in Pkd1RC/RC/Atm+/- mice. Moreover, the increase in γH2AX-positive nuclei was 1.7-fold lower in CECs compared to non-cystic epithelial cells (p < 0.05). Low-dose cisplatin also did not alter long-term disease progression in Pkd1RC/RC/Atm+/- mice. In vitro, human ADPKD cyst-derived cell lines were also resistant to cisplatin (WT9-12: 61.7 ± 4.6%; WT9-7: 64.8 ± 2.7% cell viability) compared to HK-2 (25.1 ± 4.2%), and 3D cyst growth in MDCK cells was not altered. Finally, combined low-dose cisplatin with AZD0156 (an ATM inhibitor) non-selectively reduced γH2AX in both cystic and non-cystic tubular cells and exacerbated cystic kidney disease. In conclusion, these data suggest that CECs are resistant to DNA damage, and that the combination of cisplatin with ATM inhibitors is not an effective strategy for selectively eliminating kidney cysts in ADPKD.

Keywords:  DNA damage response signaling; ataxia telangiectasia mutated; γH2AX

DOI:  https://doi.org/10.3390/ijms232012547
Kidney Int. 2022 Oct 20. pii: S0085-2538(22)00841-9. [Epub ahead of print]

Myofibroblast depletion reduces kidney cyst growth and fibrosis in autosomal dominant polycystic kidney disease.

Nidhi Dwivedi, Abeda Jamadar, Sijo Mathew, Timothy A Fields, Reena Rao.

  Autosomal dominant polycystic kidney disease (ADPKD) involves the development and persistent growth of fluid filled kidney cysts. In a recent study, we showed that ADPKD kidney cyst epithelial cells can stimulate the proliferation and differentiation of peri-cystic myofibroblasts. Although dense myofibroblast populations are often found surrounding kidney cysts, their role in cyst enlargement or fibrosis in ADPKD is unclear. To clarify this, we examined the effect of myofibroblast depletion in the Pkd1RC/RC (RC/RC) mouse model of ADPKD. RC/RC; αSMAtk mice that uses the ganciclovir-thymidine kinase system to selectively deplete α-smooth muscle actin expressing myofibroblasts were generated. Ganciclovir treatment for four weeks depleted myofibroblasts, reduced kidney fibrosis and preserved kidney function in these mice. Importantly, myofibroblast depletion significantly reduced cyst growth and cyst epithelial cell proliferation in RC/RC; αSMAtk mouse kidneys. Similar ganciclovir treatment did not alter cyst growth or fibrosis in wild type or RC/RC littermates. In vitro, co-culture with myofibroblasts from the kidneys of patients with ADPKD increased 3D microcyst growth of human ADPKD cyst epithelial cells. Treatment with conditioned culture media from ADPKD kidney myofibroblasts increased microcyst growth and cell proliferation of ADPKD cyst epithelial cells. Further examination of ADPKD myofibroblast conditioned media showed high levels of protease inhibitors including PAI1, TIMP1 and 2, NGAL and TFPI-2, and treatment with recombinant PAI1 and TIMP1 increased ADPKD cyst epithelial cell proliferation in vitro. Thus, our findings show that myofibroblasts directly promote cyst epithelial cell proliferation, cyst growth and fibrosis in ADPKD kidneys, and their targeting could be a novel therapeutic strategy to treat PKD.

Keywords:  Microenvironment; PAI1; TIMP1; cell proliferation; extracellular matrix; fibrosis; ganciclovir; thymidine kinase; α-smooth muscle actin

DOI:  https://doi.org/10.1016/j.kint.2022.08.036
Clin Nephrol. 2022 Oct 24.

PKD1 mosaicism associated with severe renal, hepatic, and vascular phenotype.

Elliott Van Regemorter, Karin Dahan, Charlotte Hougardy, Olga Ciccarelli, Nada Kanaan, Yves Pirson, Nathalie Demoulin.

Autosomal dominant polycystic kidney disease (ADPKD) is mainly caused by mutations in PKD1 or PKD2 genes. Mosaicism is characterized by a post-zygotic mutation resulting in the presence of two or more populations of cells with different genotypes in an individual. Mosaicism of PKD1, rarely identified by conventional Sanger sequencing, is more easily detected using next generation sequencing techniques (NGS). PKD1 mosaicism has classically been associated with either milder kidney disease, asymmetric kidney disease, and/or negative family history. We report the case of a patient presenting severe renal, hepatic, and vascular phenotype secondary to PKD1 mosaicism, with a surprisingly low percentage of mutant allele in the patient's kidney and liver tissue. We reviewed clinical presentations of reported cases of PKD1 mosaicism.

DOI: https://doi.org/10.5414/CN110704
Cells. 2022 Oct 20. pii: 3300. [Epub ahead of print]11(20):

Predicting Progression of Autosomal Dominant Polycystic Kidney Disease by Changes in the Telomeric Epigenome.

Ismail Kocyigit, Serpil Taheri, Cihan Uysal, Mehmet Memis, Salih Guntug Ozayturk, Gokmen Zararsiz, Minoo Rassoulzadegan.

  Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of chronic kidney disease with Polycystin&nbsp;(PKD) 1 and 2 gene mutation. However, the intra-familial variability in symptoms further suggests a non-Mendelian contribution to the disease. Our goal was to find a marker to track the epigenetic changes common to rapidly progressing forms of the disease. The risk of ADPKD increases with age, and aging shortens the telomere length (TL). Telomeres are a nucleoprotein structure composed mainly of three complexes, shelterin, CST and RNA-containing telomere repeat(TERRA), which protects the ends of chromosomes from degradation and fusion, and plays a role in maintaining cellular stability and in the repair of telomeric damage. TERRAs are transcribed from telomeric regions and a part of them is engaged in a DNA/RNA hybrid (R-loop) at each chromosome end. We tracked TL and TERRA levels in blood samples of 78 patients and 20 healthy control. Our study demonstrates that TL was shortened and TERRA expression levels in the DNA-attached fraction increased in autosomal dominant polycystic kidney patients with mutations in PKD1 and PKD2 compared to the control group. Moreover, it was observed that the expression of TERRA engaged in the R-loop was higher and the length of telomeres shorter in patients with ADPKD who showed rapid disease progression. Intrafamilial variation in TL and TERRA levels with the same mutation would indicate reliable epigenetic potential biomarkers in disease monitoring.

Keywords:  R-loop; TERRAs; epigenetics; genome integrity; lncRNA; polycystic kidney disease; telomere

DOI:  https://doi.org/10.3390/cells11203300
North Clin Istanb. 2022 ;9(4): 317-322

Evaluation of the relationship between the mean platelet volume and the neutrophil/lymphocyte ratio with progression of chronic kidney disease in patients with autosomal dominant polycystic kidney disease.

Mahmut Gok.

  OBJECTIVE: Increased inflammation is known to cause higher mortality and morbidity in autosomal dominant polycystic kidney disease (ADPKD). At the same time, inflammation has been shown to contribute in chronic kidney disease (CKD) progression pathogenesis. Neutrophil-lymphocyte ratio (NLR) and mean platelet volume (MPV) have been lately found to be related with systemic inflammation. Therefore, in this study, it was intended to evaluate any correlation between the NLR and MPV degree and poor prognosis in ADPKD patients.METHODS: The study sample comprised 86 adult patients (male: 80.2%, mean age: 35.35 years) screened in the Nephrology Outpatient Clinic with the diagnosis of ADPKD. Data were obtained from the electronic database of the hospital. Two groups were made from the patients: Group I included ADPKD patients with CKD Stages I-II and Group II included ADPKD patients with CKD Stages III-V. The relationships between CKD stage and laboratory parameters were analyzed.
RESULTS: Significantly higher NLR (2.64±1.43 vs. 2.02±0.89, p=0.024), MPV (9.84±1.65 vs. 9.08±1.17, p=0.045), and hs-CRP (10.7±2.2 vs. 22.4±8.3, p=0.001) values were determined in Group II than in those with Group I. Positive correlations were statistically significative observed between hs-CRP and MPV and NLR in the patients with ADPKD.
CONCLUSION: The study results demonstrated that significantly NLR and MPV are increased in ADPKD patients with progression of CKD. Therefore, lowering the NLR and MPV level could be new, therapeutic, and preventive alternatives for patients with ADPKD.

Keywords:  C-reactive protein; inflammation; mean platelet volume; polycystic kidney disease

DOI:  https://doi.org/10.14744/nci.2021.89657
J Clin Med. 2022 Oct 11. pii: 5982. [Epub ahead of print]11(20):

Echocardiographic Abnormalities in Autosomal Dominant Polycystic Kidney Disease (ADPKD) Patients.

Mariana Becker Pfeferman, Daniel Ribeiro da Rocha, Fernanda Guedes Rodrigues, Elcio Pfeferman, Ita Pfeferman Heilberg.

  Cardiovascular abnormalities, such as left ventricular hypertrophy and valvular disorders, particularly mitral valve prolapse, have been described as highly prevalent among adult patients with autosomal dominant polycystic kidney disease (ADPKD). The present study aimed to assess echocardiographic parameters in a large sample of both normotensive and hypertensive ADPKD patients, regardless of kidney function level, and evaluate their association with clinical and laboratorial parameters. A retrospective study consisted of the analysis of clinical, laboratorial, and transthoracic echocardiograms data retrieved from the medical records of young adult ADPKD outpatients. A total of 294 patients (120 M/174 F, 41.0 ± 13.8 years old, 199 hypertensive and 95 normotensive) with a median estimated glomerular filtration rate (eGFR) of 75.5 mL/min/1.73 m2 were included. The hypertensive group (67.6%) was significantly older and exhibited significantly lower eGFR than the normotensive one. Increased left ventricular mass index (LVMI) was seen in 2.0%, mitral valve prolapse was observed in 3.4%, mitral valve regurgitation in 15.3%, tricuspid valve regurgitation in 16.0%, and aortic valve regurgitation in 4.8% of the whole sample. The present study suggested that the prevalence of mitral valve prolapse was much lower than previously reported, and increased LVMI was not seen in most adult ADPKD patients.

Keywords:  ADPKD; cardiovascular; echocardiogram; left ventricular mass index; mitral valve prolapse; polycystic disease; valvar abnormalities

DOI:  https://doi.org/10.3390/jcm11205982
Kidney Int. 2022 Oct 22. pii: S0085-2538(22)00847-X. [Epub ahead of print]

Enhancer and super-enhancer landscape in polycystic kidney disease.

Ronak Lakhia, Abheepsa Mishra, Laurence Biggers, Venkat Malladi, Patricia Cobo-Stark, Sachin Hajarnis, Vishal Patel.

  Widespread aberrant gene expression is a pathological hallmark of polycystic kidney disease (PKD). Numerous pathogenic signaling cascades, including c-Myc, Fos, and Jun are transactivated. However, the underlying epigenetic regulators are poorly defined. Here we show that H3K27ac, an acetylated modification of DNA packing protein histone H3 that marks active enhancers, is elevated in mouse and human samples of autosomal dominant PKD. Using comparative H3K27ac ChIP-Seq analysis, we mapped over 16000 active intronic and intergenic enhancer elements in Pkd1-mutant mouse kidneys. We found that the cystic kidney epigenetic landscape resembles that of a developing kidney, and over 90% of upregulated genes in Pkd1-mutant kidneys are co-housed with activated enhancers in the same topologically associated domains. Furthermore, we identified an evolutionarily-conserved enhancer cluster downstream of the c-Myc gene and super-enhancers flanking both Jun and Fos loci in mouse and human models of autosomal dominant PKD. Deleting these regulatory elements reduced c-Myc, Jun, or Fos abundance and suppressed proliferation and 3D cyst growth of Pkd1-mutant cells. Finally, inhibiting glycolysis and glutaminolysis or activating Ppara in Pkd1-mutant cells lowerd global H3K27ac levels and its abundance on c-Myc enhancers. Thus, our work suggests that epigenetic rewiring mediates the transcriptomic dysregulation in PKD, and the regulatory elements can be targeted to slow cyst growth.

Keywords:  ChIP-Seq; Fos; H3K27ac; Jun; Polycystic kidney disease; c-Myc; enhancers; epigenetics; super-enhancers

DOI:  https://doi.org/10.1016/j.kint.2022.08.039
Front Endocrinol (Lausanne). 2022 ;13 1005639

Involvement of ceramide biosynthesis in increased extracellular vesicle release in Pkd1 knock out cells.

Valentina Carotti, Jenny van der Wijst, Eric H J Verschuren, Luco Rutten, Nico Sommerdijk, Charlotte Kaffa, Vera Sommers, Juan P Rigalli, Joost G J Hoenderop.

  Autosomal Dominant Polycystic Kidney Disease (ADPKD) is an inherited disorder characterized by the development of renal cysts, which frequently leads to renal failure. Hypertension and other cardiovascular symptoms contribute to the high morbidity and mortality of the disease. ADPKD is caused by mutations in the PKD1 gene or, less frequently, in the PKD2 gene. The disease onset and progression are highly variable between patients, whereby the underlying mechanisms are not fully elucidated. Recently, a role of extracellular vesicles (EVs) in the progression of ADPKD has been postulated. However, the mechanisms stimulating EV release in ADPKD have not been addressed and the participation of the distal nephron segments is still uninvestigated. Here, we studied the effect of Pkd1 deficiency on EV release in wild type and Pkd1-/- mDCT15 and mIMCD3 cells as models of the distal convoluted tubule (DCT) and inner medullary collecting duct (IMCD), respectively. By using nanoparticle tracking analysis, we observed a significant increase in EV release in Pkd1-/- mDCT15 and mIMCD3 cells, with respect to the wild type cells. The molecular mechanisms leading to the changes in EV release were further investigated in mDCT15 cells through RNA sequencing and qPCR studies. Specifically, we assessed the relevance of purinergic signaling and ceramide biosynthesis enzymes. Pkd1-/- mDCT15 cells showed a clear upregulation of P2rx7 expression compared to wild type cells. Depletion of extracellular ATP by apyrase (ecto-nucleotidase) inhibited EV release only in wild type cells, suggesting an exacerbated signaling of the extracellular ATP/P2X7 pathway in Pkd1-/- cells. In addition, we identified a significant up-regulation of the ceramide biosynthesis enzymes CerS6 and Smpd3 in Pkd1-/- cells. Altogether, our findings suggest the involvement of the DCT in the EV-mediated ADPKD progression and points to the induction of ceramide biosynthesis as an underlying molecular mechanism. Further studies should be performed to investigate whether CerS6 and Smpd3 can be used as biomarkers of ADPKD onset, progression or severity.

Keywords:  ADPKD; Autosomal Dominant Polycistic Kidney Disease; exosomes; extracellular ATP; extracellular vesicles; purinergic signaling

DOI:  https://doi.org/10.3389/fendo.2022.1005639
Sci Rep. 2022 Oct 27. 12(1): 18056

Impact of kidney function and kidney volume on intracranial aneurysms in patients with autosomal dominant polycystic kidney disease.

Hiroshi Kataoka, Hiroyuki Akagawa, Rie Yoshida, Naomi Iwasa, Yusuke Ushio, Taro Akihisa, Masayo Sato, Shun Manabe, Shiho Makabe, Keiko Kawachi, Junichi Hoshino, Ken Tsuchiya, Kosaku Nitta, Toshio Mochizuki.

Presently, only personal or family history of intracranial aneurysm/subarachnoid hemorrhage (IA/SAH) has been established as a risk factor for IA in autosomal dominant polycystic kidney disease (ADPKD). This study aimed to verify the association between kidney function/volume and IAs in patients with ADPKD. This study included 519 patients with ADPKD. At baseline IA screening, the median age and estimated glomerular filtration rate were 44 years and 54.5 mL/min/1.73 m2, respectively. Family IA/SAH history was confirmed in 18.1% of the patients, and 54.3% of the patients had hypertension. The IA point prevalence was 12.5%. During clinical follow up of 3104 patient-years, de novo IA was detected in 29 patients (0.93% patient-years). The IA period prevalence was 18.1% (median age, 60 years). Multivariable logistic regression demonstrated that total kidney volume (TKV) ≥ 1000 mL (odds ratio [OR] = 2.81), height-adjusted TKV ≥ 500 mL (OR = 2.81), Mayo imaging classification Class 1D-1E (OR = 2.52), and chronic kidney disease stages 3-5 (OR = 2.31) were significantly associated with IA formation. IAs in patients with ADPKD may be associated not only with general risk factors for IAs but also with declining kidney function and increased KV. Kidney disease progression may contribute to effective IA screening and treatment planning in patients with ADPKD.

DOI: https://doi.org/10.1038/s41598-022-22884-9
Mol Med Rep. 2022 Dec;pii: 365. [Epub ahead of print]26(6):

Visual inspection reveals a novel pathogenic mutation in PKD1 missed by the variant caller in whole‑exome sequencing.

Bee Tee Koay, Mei Yee Chiow, Jamiila Ismail, Norfarhana Khairul Fahmy, Seow Yeing Yee, Norhazlin Mustafa, Masita Arip, Adiratna Mat Ripen, Saharuddin Bin Mohamad.

  Autosomal dominant polycystic kidney disease (ADPKD) is the most common type of inherited cystic kidney disease. The feasibility of whole‑exome sequencing (WES) to obtain molecular diagnosis of ADPKD is still in question as previous studies showed conflicting results. Utilizing WES on a patient with ADPKD, standard bioinformatics pipeline demonstrated no pathogenic variant in the genes of interest. By visualizing read alignments using the Integrative Genomics Viewer, a region with atypical alignment of numerous soft‑clipped reads at exon 45 of polycystin 1, transient receptor potential channel interacting (PKD1) gene was demonstrated. A total of four visual inspection steps were outlined to assess the origin of these soft‑clipped reads as strand bias during capture, poor mapping, sequencing error or DNA template contamination. Following assessment, the atypical alignment at PKD1 was hypothesized to be caused by an insertion/deletion mutation. Sanger sequencing confirmed the presence of a novel 20‑bp insertion in PKD1 (NM_001009944.3; c.12143_12144insTCCCCGCAGTCTTCCCCGCA; p.Val4048LeufsTer157), which introduced a premature stop codon and was predicted to be pathogenic. The present study demonstrated that WES could be utilized as a molecular diagnostic tool for ADPKD. Furthermore, visual inspection of read alignments was key in identifying the pathogenic variant. The proposed visual inspection steps may be incorporated into a typical WES data analysis workflow to improve the diagnostic yield.

Keywords:  ADPKD; IGV; WES; polycystin 1; soft‑clipped; transient receptor potential channel interacting; visual inspection

DOI:  https://doi.org/10.3892/mmr.2022.12882
Nat Genet. 2022 Oct 27.

Adult human kidney organoids originate from CD24+ cells and represent an advanced model for adult polycystic kidney disease.

Yaoxian Xu, Christoph Kuppe, Javier Perales-Patón, Sikander Hayat, Jennifer Kranz, Ali T Abdallah, James Nagai, Zhijian Li, Fabian Peisker, Turgay Saritas, Maurice Halder, Sylvia Menzel, Konrad Hoeft, Annegien Kenter, Hyojin Kim, Claudia R C van Roeyen, Michael Lehrke, Julia Moellmann, Thimoteus Speer, Eva M Buhl, Remco Hoogenboezem, Peter Boor, Jitske Jansen, Cordula Knopp, Ingo Kurth, Bart Smeets, Eric Bindels, Marlies E J Reinders, Carla Baan, Joost Gribnau, Ewout J Hoorn, Joachim Steffens, Tobias B Huber, Ivan Costa, Jürgen Floege, Rebekka K Schneider, Julio Saez-Rodriguez, Benjamin S Freedman, Rafael Kramann.

Adult kidney organoids have been described as strictly tubular epithelia and termed tubuloids. While the cellular origin of tubuloids has remained elusive, here we report that they originate from a distinct CD24+ epithelial subpopulation. Long-term-cultured CD24+ cell-derived tubuloids represent a functional human kidney tubule. We show that kidney tubuloids can be used to model the most common inherited kidney disease, namely autosomal dominant polycystic kidney disease (ADPKD), reconstituting the phenotypic hallmark of this disease with cyst formation. Single-cell RNA sequencing of CRISPR-Cas9 gene-edited PKD1- and PKD2-knockout tubuloids and human ADPKD and control tissue shows similarities in upregulation of disease-driving genes. Furthermore, in a proof of concept, we demonstrate that tolvaptan, the only approved drug for ADPKD, has a significant effect on cyst size in tubuloids but no effect on a pluripotent stem cell-derived model. Thus, tubuloids are derived from a tubular epithelial subpopulation and represent an advanced system for ADPKD disease modeling.

DOI: https://doi.org/10.1038/s41588-022-01202-z
J Cell Biochem. 2022 Oct 28.

PDGF-AA activates AKT and ERK signaling for testicular interstitial Leydig cell growth via primary cilia.

Yung-Chieh Tsai, Tian-Ni Kuo, Yu-Ying Chao, Pei-Rong Lee, Ruei-Ci Lin, Xiao-Yi Xiao, Bu-Miin Huang, Chia-Yih Wang.

  Testes control the development of male reproductive system. The testicular interstitial Leydig cells (Leydig cells) synthesize testosterone for promoting spermatogenesis and secondary sexual characteristics. Type A platelet-derived growth factor (PDGF-AA) is one of the most important growth factors in regulating Leydig cell growth and function. Knockout of PDGF-AA or its congenital receptor PDGFR-α leads to poor testicular development caused by reducing Leydig cell numbers, supporting PDGF-AA/PDGFR-α signaling regulates Leydig cell development. Primary cilium is a cellular antenna that functions as an integrative platform to transduce extracellular signaling for proper development and differentiation. Several receptors including PDGFR-α are observed on primary cilia for initiating signaling cascades in distinct cell types. Here we showed that PDGF-AA/PDGFR-α signaling promoted Leydig cells growth, migration, and invasion via primary cilia. Upon PDGF-AA treatment, AKT and ERK signaling were activated to regulate these cellular events. Interestingly, active AKT and ERK were detected around the base of primary cilia. Depletion of ciliary genes (IFT88 and CEP164) alleviated PDGF-AA-activated AKT and ERK, thus reducing Leydig cell growth, migration, and invasion. Thus, our study not only reveals the function of PDGF-AA/PDGFR-α signaling in maintaining testicular physiology but also uncovers the role of primary cilium and downstream signaling in regulating Leydig cell development.

Keywords:  Leydig cell; PDGF-AA; PDGFR-a; cell growth; invasion; migration; primary cilium

DOI:  https://doi.org/10.1002/jcb.30345
iScience. 2022 Nov 18. 25(11): 105262

Kinesin-2 motors differentially impact biogenesis of extracellular vesicle subpopulations shed from sensory cilia.

Michael Clupper, Rachael Gill, Malek Elsayyid, Denis Touroutine, Jeffrey L Caplan, Jessica E Tanis.

  Extracellular vesicles (EVs) are bioactive lipid-bilayer enclosed particles released from nearly all cells. One specialized site for EV shedding is the primary cilium. Here, we discover the conserved ion channel CLHM-1 as a ciliary EV cargo. Imaging of EVs released from sensory neuron cilia of Caenorhabditis elegans expressing fluorescently tagged CLHM-1 and TRP polycystin-2 channel PKD-2 shows enrichment of these cargoes in distinct EV subpopulations that are differentially shed in response to mating partner availability. PKD-2 alone is present in EVs shed from the cilium distal tip, whereas CLHM-1 EVs bud from a secondary site(s), including the ciliary base. Heterotrimeric and homodimeric kinesin-2 motors have discrete impacts on PKD-2 and CLHM-1 colocalization in both cilia and EVs. Total loss of kinesin-2 activity decreases shedding of PKD-2 but not CLHM-1 EVs. Our data demonstrate that anterograde intraflagellar transport is required for selective enrichment of protein cargoes into heterogeneous EVs with different signaling potentials.

Keywords:  Molecular neuroscience; Natural sciences; Neuroscience

DOI:  https://doi.org/10.1016/j.isci.2022.105262
MicroPubl Biol. 2022 ;2022

A ccpp-6 deletion mutation does not impair gross cilia integrity in C. elegans.

Jessica Dominguez, Bhumi P Shah, Nina Peel.

Tubulin glutamylation is a reversible modification that regulates microtubule function in cilia. The removal of glutamylation from microtubules is carried out by a family of cytosolic carboxypeptidase (CCP) enzymes. C. elegans has two deglutamylating enzymes, CCPP-1 and CCPP-6, homologs of mammalian CCP1 and CCP5 respectively. CCPP-1 is required for ciliary stability and function. To determine whether CCPP-6 is similarly required for cilia integrity in C. elegans we analyzed the ccpp-6(ok382) deletion mutant. We find that both dye-filling and male mating are normal, suggesting that CCPP-6 is not required for ciliary integrity in C. elegans.

DOI: https://doi.org/10.17912/micropub.biology.000649
J Clin Med. 2022 Oct 15. pii: 6084. [Epub ahead of print]11(20):

Management of Renal Angiomyolipomas in Tuberous Sclerosis Complex: A Case Report and Literature Review.

Mitchell Hunter-Dickson, Patrick Wu, Akshay Athavale, Amanda Ying Wang.

  We report a case of misdiagnosed tuberous sclerosis complex (TSC) in a patient without TSC gene variant presenting with bilateral renal angiomyolipomas and seizures in the context of strong family history of polycystic kidney disease. Clinical diagnosis of tuberous sclerosis complex was made and treatment with everolimus reduced size of renal angiomyolipomas. In this case, report we discuss the association between tuberous sclerosis complex and polycystic kidney disease and novel treatment for TSC.

Keywords:  angiomyolipoma; cystic kidney disease; everolimus; genetics; tuberous sclerosis

DOI:  https://doi.org/10.3390/jcm11206084
Front Genet. 2022 ;13 1017280

Identification of a novel founder variant in DNAI2 cause primary ciliary dyskinesia in five consanguineous families derived from a single tribe descendant of Arabian Peninsula.

Dalal A Al-Mutairi, Basel H Alsabah, Bashar A Alkhaledi, Petra Pennekamp, Heymut Omran.

  Introduction: Primary ciliary dyskinesia (PCD) is caused by dysfunction of motile cilia resulting in insufficient mucociliary clearance of the lungs. The overall aim of this study is to identify disease causing genetic variants for PCD patients in the Kuwaiti population. Methods: A cohort of multiple consanguineous PCD families was identified from Kuwaiti patients and genomic DNA from the family members was analysed for variant screening. Transmission electron microscopy (TEM) and immunofluorescent (IF) analyses were performed on nasal brushings to detect specific structural abnormalities within ciliated cells. Results: All the patients inherited the same founder variant in DNAI2 and exhibited PCD symptoms. TEM analysis demonstrated lack of outer dynein arms (ODA) in all analysed samples. IF analysis confirmed absence of DNAI1, DNAI2, and DNAH5 from the ciliary axoneme. Whole exome sequencing, autozygosity mapping and segregation analysis confirmed that seven patients carry the same homozygous missense variant (DNAI2:c.740G>A; p.Arg247Gln; rs755060592). Conclusion: DNAI2:c.740G>A is the founder variant causing PCD in patients belonging to a particular Arabian tribe which practices consanguineous marriages.

Keywords:  DNAI2 gene; consanguinity; genetics of ciliopathy; primary ciliary dyskinesia; pulmonary disease

DOI:  https://doi.org/10.3389/fgene.2022.1017280
Clin Genet. 2022 Oct 23.

Biallelic variants in CEP164 cause a motile ciliopathy-like syndrome.

Genomics England Research Consortium

  Ciliopathies may be classed as primary or motile depending on the underlying ciliary defect and are usually considered distinct clinical entities. Primary ciliopathies are associated with multisystem syndromes typically affecting the brain, kidney, and eye, as well as other organ systems such as the liver, skeleton, auditory system, and metabolism. Motile ciliopathies are a heterogenous group of disorders with defects in specialised motile ciliated tissues found within the lung, brain, and reproductive system, and are associated with primary ciliary dyskinesia, bronchiectasis, infertility and rarely hydrocephalus. Primary and motile cilia share defined core ultra-structures with an overlapping proteome, and human disease phenotypes can reflect both primary and motile ciliopathies. CEP164 encodes a centrosomal distal appendage protein vital for primary ciliogenesis. Human CEP164 mutations are typically described in patients with nephronophthisis-related primary ciliopathies but have also been implicated in motile ciliary dysfunction. Here we describe a patient with an atypical motile ciliopathy phenotype and biallelic CEP164 variants. This work provides further evidence that CEP164 mutations can contribute to both primary and motile ciliopathy syndromes, supporting their functional and clinical overlap, and informs the investigation and management of CEP164 ciliopathy patients.

Keywords:  CEP164; genetics; ciliopathy; mutation; primary ciliary dyskinesia

DOI:  https://doi.org/10.1111/cge.14251
Mol Biol Cell. 2022 Oct 26. mbcE22100468T

Basal bodies bend in response to ciliary forces.

Anthony D Junker, Louis G Woodhams, Adam W J Soh, Eileen T O'Toole, Philip V Bayly, Chad G Pearson.

Motile cilia beat with an asymmetric waveform consisting of a power stroke that generates a propulsive force and a recovery stroke that returns the cilium back to the start. Cilia are anchored to the cell cortex by basal bodies (BBs) that are directly coupled to the ciliary doublet MTs. We find that, consistent with ciliary forces imposing on BBs, bending patterns in BB triplet MTs are responsive to ciliary beating. BB bending varies as environmental conditions change the ciliary waveform. Bending occurs where striated fibers (SF) attach to BBs and mutants with short SFs that fail to connect to adjacent BBs exhibit abnormal BB bending, supporting a model in which SFs couple ciliary forces between BBs. Finally, loss of the BB stability protein, Poc1, that helps interconnect BB triplet MTs prevents the normal distributed BB and ciliary bending patterns. Collectively, BBs experience ciliary forces and manage mechanical coupling of these forces to their surrounding cellular architecture for normal ciliary beating. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].

DOI: https://doi.org/10.1091/mbc.E22-10-0468-T
EMBO Rep. 2022 Oct 25. e55687

Loss of primary cilia promotes inflammation and carcinogenesis.

Conception Paul, Ruizhi Tang, Ciro Longobardi, Rossano Lattanzio, Thibaut Eguether, Hulya Turali, Julie Bremond, Chloé Maurizy, Monica Gabola, Sophie Poupeau, Andrei Turtoi, Emilie Denicolai, Maria Concetta Cufaro, Magali Svrcek, Philippe Seksik, Vincent Castronovo, Philippe Delvenne, Vincenzo de Laurenzi, Quentin Da Costa, François Bertucci, Bénédicte Lemmers, Damiana Pieragostino, Emilie Mamessier, Carsten Janke, Valérie Pinet, Michael Hahne.

  Primary cilia (PC) are important signaling hubs, and we here explored their role in colonic pathology. In the colon, PC are mostly present on fibroblasts, and exposure of mice to either chemically induced colitis-associated colon carcinogenesis (CAC) or dextran sodium sulfate (DSS)-induced acute colitis decreases PC numbers. We generated conditional knockout mice with reduced numbers of PC on colonic fibroblasts. These mice show increased susceptibility to CAC, as well as DSS-induced colitis. Secretome and immunohistochemical analyses of DSS-treated mice display an elevated production of the proinflammatory cytokine IL-6 in PC-deficient colons. An inflammatory environment diminishes PC presence in primary fibroblast cultures, which is triggered by IL-6 as identified by RNA-seq analysis together with blocking experiments. These findings suggest an activation loop between IL-6 production and PC loss. An analysis of PC presence on biopsies of patients with ulcerative colitis or colorectal cancer (CRC) reveals decreased numbers of PC on colonic fibroblasts in pathological compared with surrounding normal tissue. Taken together, we provide evidence that a decrease in colonic PC numbers promotes colitis and CRC.

Keywords:  colitis; colon carcinogenesis; colonic fibroblasts; inflammation; primary cilia

DOI:  https://doi.org/10.15252/embr.202255687
Int J Mol Sci. 2022 Oct 12. pii: 12147. [Epub ahead of print]23(20):

IFT20: An Eclectic Regulator of Cellular Processes beyond Intraflagellar Transport.

Francesca Finetti, Anna Onnis, Cosima T Baldari.

  Initially discovered as the smallest component of the intraflagellar transport (IFT) system, the IFT20 protein has been found to be implicated in several unconventional mechanisms beyond its essential role in the assembly and maintenance of the primary cilium. IFT20 is now considered a key player not only in ciliogenesis but also in vesicular trafficking of membrane receptors and signaling proteins. Moreover, its ability to associate with a wide array of interacting partners in a cell-type specific manner has expanded the function of IFT20 to the regulation of intracellular degradative and secretory pathways. In this review, we will present an overview of the multifaceted role of IFT20 in both ciliated and non-ciliated cells.

Keywords:  IFT20; intraflagellar transport system; primary cilium; vesicular traffic

DOI:  https://doi.org/10.3390/ijms232012147
Am J Physiol Heart Circ Physiol. 2022 Oct 28.

Hypertension is Linked to Enhanced Lymphatic Contractile Response via RGS16/RhoA/ROCK Pathway.

Masashi Mukohda, Risuke Mizuno, Fumiyo Saito, Toshiyasu Matsui, Hiroshi Ozaki.

  Lymph capillary network can be expected to alter blood pressure via regulating interstitial electrolyte and volume balance. However, the pathophysiology of lymphatic vessel in hypertension is poorly understood. In this study, we examined lymph vessel function focusing on contractile response in hypertensive rats. It was found that thoracic ducts isolated from adult (10-14-week-old) spontaneously hypertensive rats (SHRs) exhibited increased agonist-mediated contraction compared with age-matched Wistar-Kyoto (WKY) rats, whereas lymphatic contractions in younger (4-week-old) SHRs, exhibiting normal blood pressure, were no different compared with age-matched control rats. Tight regulation of blood pressure with antihypertensive drugs (hydrochlorothiazide/hydralazine) did not prevent the augmented lymphatic contraction in adult SHRs; however, treatment of SHRs with angiotensin II (Ang II) type 1 receptor blocker (losartan) for 6 weeks abolished the augmentation of lymphatic contractions. Additionally, Ang II infusion in Wistar rat caused augmented lymphatic contractile responses in the thoracic duct. The augmented contractions in adult SHRs were diminished by a ROCK inhibitor (Y-27632). Consistently, the thoracic ducts in SHRs showed significantly higher phosphorylation of myosin phosphatase targeting protein-1 than WKY rats. Furthermore, gene expression profiling of adult SHR lymphatics showed marked loss of regulator of G protein signaling 16 (RGS16) mRNA, which was confirmed by the real-time PCR. Treatment with the RGS inhibitor CCG-63808 enhanced contractions in thoracic ducts from Wistar rats, which were abolished by the ROCK inhibitor. It is concluded that lymphatic contractile function was enhanced in hypertensive model rats, which could be mediated by dysregulation of the ROCK pathway possibly through RGS16.

Keywords:  Angiotensin II; Hypertension; Lymphatics; RGS; ROCK

DOI:  https://doi.org/10.1152/ajpheart.00496.2022
Front Cell Dev Biol. 2022 ;10 995847

Predicting the locations of force-generating dyneins in beating cilia and flagella.

Jonathon Howard, Alexander Chasteen, Xiaoyi Ouyang, Veikko F Geyer, Pablo Sartori.

  Cilia and flagella are slender cylindrical organelles whose bending waves propel cells through fluids and drive fluids across epithelia. The bending waves are generated by dynein motor proteins, ATPases whose force-generating activity changes over time and with position along the axoneme, the motile structure within the cilium. A key question is: where, in an actively beating axoneme, are the force-generating dyneins located? Answering this question is crucial for determining which of the conformational states adopted by the dynein motors generate the forces that bend the axoneme. The question is difficult to answer because the flagellum contains a large number of dyneins in a complex three-dimensional architecture. To circumvent this complexity, we used a molecular-mechanics approach to show how the bending moments produced by single pairs of dynein motors work against elastic and hydrodynamic forces. By integrating the individual motor activities over the length of the axoneme, we predict the locations of the force-generating dyneins in a beating axoneme. The predicted location depends on the beat frequency, the wavelength, and the elastic and hydrodynamic properties of the axoneme. To test these predictions using cryogenic electron microscopy, cilia with shorter wavelengths, such as found in Chlamydomonas, are more suitable than sperm flagella with longer wavelengths because, in the former, the lag between force and curvature is less dependent on the specific mechanical properties and experimental preparation.

Keywords:  axoneme; cilium; dynein; flagellum; force

DOI:  https://doi.org/10.3389/fcell.2022.995847