bims-bicyki Biomed News
on Bicaudal-C1 and interactors in cystic kidney disease
Issue of 2021‒01‒17
four papers selected by
Céline Gagnieux
École Polytechnique Fédérale de Lausanne (EPFL)

  1. Eur J Hum Genet. 2021 Jan 12.
      Autosomal Dominant Polycystic Kidney Disease (ADPKD) is common, with a prevalence of 1/1000 and predominantly caused by disease-causing variants in PKD1 or PKD2. Clinical diagnosis is usually by age-dependent imaging criteria, which is challenging in patients with atypical clinical features, without family history, or younger age. However, there is increasing need for definitive diagnosis of ADPKD with new treatments available. Sequencing is complicated by six pseudogenes that share 97% homology to PKD1 and by recently identified phenocopy genes. Whole-genome sequencing can definitively diagnose ADPKD, but requires validation for clinical use. We initially performed a validation study, in which 42 ADPKD patients underwent sequencing of PKD1 and PKD2 by both whole-genome and Sanger sequencing, using a blinded, cross-over method. Whole-genome sequencing identified all PKD1 and PKD2 germline pathogenic variants in the validation study (sensitivity and specificity 100%). Two mosaic variants outside pipeline thresholds were not detected. We then examined the first 144 samples referred to a clinically-accredited diagnostic laboratory for clinical whole-genome sequencing, with targeted-analysis to a polycystic kidney disease gene-panel. In this unselected, diagnostic cohort (71 males :73 females), the diagnostic rate was 70%, including a diagnostic rate of 81% in patients with typical ADPKD (98% with PKD1/PKD2 variants) and 60% in those with atypical features (56% PKD1/PKD2; 44% PKHD1/HNF1B/GANAB/ DNAJB11/PRKCSH/TSC2). Most patients with atypical disease did not have clinical features that predicted likelihood of a genetic diagnosis. These results suggest clinicians should consider diagnostic genomics as part of their assessment in polycystic kidney disease, particularly in atypical disease.
  2. Zhonghua Yi Xue Yi Chuan Xue Za Zhi. 2021 Jan 10. 38(1): 47-51
      OBJECTIVE: To detect the mutation site in a pedigree affected with autosomal dominant polycystic kidney disease (ADPKD) and verify its impact on the protein function.METHODS: Peripheral blood samples were collected from the proband and his pedigree members for the extraction of genomic DNA. Mutational analysis was performed on the proband through whole-exome sequencing. Suspected variant was verified by Sanger sequencing. A series of molecular methods including PCR amplification, restriction enzyme digestion, ligation and transformation were also used to construct wild-type and mutant eukaryotic expression vectors of the PKD2 gene, which were transfected into HEK293T and HeLa cells for the observation of protein expression and cell localization.
    RESULTS: The proband was found to harbor a c.2051dupA (p. Tyr684Ter) frame shift mutation of the PKD2 gene, which caused repeat of the 2051st nucleotide of its cDNA sequence and a truncated protein. Immunofluorescence experiment showed that the localization of the mutant protein within the cell was altered compared with the wild-type, which may be due to deletion of the C-terminus of the PKD2 gene.
    CONCLUSION: The c.2051dupA (p. Tyr684Ter) mutation of the PKD2 gene probably underlay the pathogenesis of ADPKD in this pedigree.
  3. Front Immunol. 2020 ;11 607564
      Conjugated polyenes are a class of widely occurring natural products with various biological functions. We previously identified 4-hydroxy auxarconjugatin B (4-HAB) as anti-inflammatory agent with an IC50 of ~20 µM. In this study, we synthesized a new anti-inflammatory 4-HAB analogue, F240B, which has an IC50 of less than 1 µM. F240B dose-dependently induced autophagy by increasing autophagic flux, LC3 speck formation and acidic vesicular organelle formation. F240B inhibited NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome activation through autophagy induction. In a mechanistic study, F240B inhibited interleukin (IL)-1β (IL-1β) precursor expression, promoted degradation of NLRP3 and IL-1β, and reduced mitochondrial membrane integrity loss in an autophagy-dependent manner. Additionally, F240B inhibited apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization and speck formation without affecting the interaction between NLRP3 and ASC or NIMA-related kinase 7 (NEK7) and double-stranded RNA-dependent kinase (PKR). Furthermore, F240B exerted in vivo anti-inflammatory activity by reducing the intraperitoneal influx of neutrophils and the levels of IL-1β, active caspase-1, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in lavage fluids in a mouse model of uric acid crystal-induced peritonitis. In conclusion, F240B attenuated the NLRP3 inflammasome through autophagy induction and can be developed as an anti-inflammatory agent in the future.
    Keywords:  NLRP3 inflammasome; autophagy; conjugated polyenes; mitochondria; peritonitis
  4. J Biol Regul Homeost Agents. 2020 Nov-Dec;34(6):34(6): 2049-2058
      Long non-coding ribonucleic acids (lncRNAs) have been recognized as markers in several cancers and play important roles in glioblastoma (GBM). But the role of lncRNA X inactive-specific transcript (XIST) in GBM and its possible mechanisms are rarely studied in depth. This study was conducted to explore the detailed roles of XIST in cell proliferation, migration, and invasion of GBM. Expressions of XIST, miR-448, and ρ associated coiled coil containing protein kinase 1 (ROCK1) were detected by qRT-PCR or Western blot in A172 and U251 cells. The interactions among XIST, miR-448 and ROCK1 were verified through luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Cell Counting Kit-8 (CCK-8) assay and Transwell assay were introduced to detect how XIST knockdown, miR-448 overexpression, or along with ROCK1 overexpression affect cellular malignancy of GBM cells. XIST and ROCK1 were up-regulated while miR-448 expression was decreased in GBM cells. XIST knockdown or miR-448 overexpression could dramatically inhibit GBM cell proliferation, migration, and invasion. Moreover, XIST negatively regulated miR-448 expression through the function as competing endogenous RNA (ceRNA), thus leading to the up-regulation of ROCK1, one miR-448 target gene. Moreover, ROCK1 overexpression could reverse the suppression of XIST knockdown or miR-448 upregulation on cellular malignancy. In brief, the effects of XIST may promote cellular malignancy of GBM through miR-448/ROCK1 axis, which will provide new understanding of GBM pathogenesis and progression.
    Keywords:  ROCK1; XIST; cellular malignancy; glioblastoma; miR-448