Biology subjects

Namba, M.

Publications and source records attributed to Namba, M..

2 recordsLinked to original sources

bioRxiv2021

Creation of X-linked Alport Syndrome Rat Model with Col4a5 Deficiency

Alport syndrome is an inherited chronic human kidney disease, characterized by glomerular basement membrane abnormalities. This disease is caused by mutations in COL4A3, COL4A4, or COL4A5 gene. The knockout mice for Col43, Col44, and Col45 are developed and well characterized for the study of Alport syndrome. However, disease progression and effects of pharmacological therapy depend on the genetic variability. This model is reliable only to mice. Therefore in this study, we created a novel Alport syndrome rat model utilizing rGONAD technology. Col45 deficient rats showed hematuria, proteinuria, high levels of BUN, Cre, and then died at 18 to 28 weeks of age (Hemizygous mutant males). Histological and ultrastructural analyses displayed the abnormalities including parietal cell hyperplasia, mesangial sclerosis, and interstitial fibrosis. Then, we demonstrated that 3/4/5 (IV) and 5/5/6 (IV) chains of type IV collagen disrupted in the Col45 deficient rats. Moreover, immunofluorescence analyses revealed that some glomeruli of Col45 mutant rats were found to be disrupted from postnatal day 0. Thus, Col45 mutant rat is a reliable candidate for Alport syndrome model for underlying the mechanism of renal diseases and further identifying potential therapeutic targets for human renal diseases.

bioengineering↗

bioRxiv2019

The p21 dependent G2 arrest of the cell cycle in epithelial tubular cells links to the early stage of renal fibrosis

Renal fibrosis is accompanied with the progression of chronic kidney disease (CKD). Despite a number of past and ongoing studies, our understanding of the underlying mechanisms remains elusive. Here we explored the progression of renal fibrosis by using a mouse model, unilateral ureter obstruction (UUO). We found that in the initial stage of the progression where extracellular matrix did not deposit yet, the proximal tubular cells arrested at the G2 of the cell cycle. This G2 arrest was induced prior to activation of both DNA damage checkpoint and Wnt/{beta}-Catenin pathway. Further analyses in vivo and in vitro indicated the cyclin dependent kinase inhibitor p21 is involved in the G2 arrest after the damage. The newly produced monoclonal antibody against p21 revealed that the p21 levels were sharply upregulated in response to the damage during the initial stage, but dropped down toward the later stage. To examine the function of p21 in the progression of renal fibrosis, we constructed the novel p21 deficient mice by i-GONAD. Compared with wild-type mice, p21 deficient mice showed the exacerbation of the fibrosis. Thus we propose that during the initial stage of the fibrosis following the renal damage, tubular cells arrest in the G2 phase depending on p21, thereby safeguarding the kidney functions.

cell biology↗