Kidney Week

Abstract: TH-PO1185

p38 Phosphorylation in Proximal Tubular Cells Induces Cellular Senescence and Contributes to Kidney Disease Progression

Session Information

• CKD: Mechanisms, AKI, and Beyond - 1
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2303 CKD (Non-Dialysis): Mechanisms

Authors

• Iwashige, Yohei, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Yohei Iwashige, MD

• Yamada, Ryo, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Ryo Yamada, MD

• Konishi, Ryo, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Ryo Konishi

• Morita, Keisuke, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Keisuke Morita, MD

• Morinishi, Takuya, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Takuya Morinishi, MD

• Muro, Koji, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Koji Muro, MD

• Yamamoto, Shigenori, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Shigenori Yamamoto, MD

• Yamamoto, Shinya, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Shinya Yamamoto, MD, PhD

• Yamada, Yasuhiro, Tokyo Daigaku, Bunkyo, Tokyo, Japan

Yasuhiro Yamada, MD, PhD

• Yanagita, Motoko, Kyoto Daigaku, Kyoto, Kyoto Prefecture, Japan

Motoko Yanagita, MD, PhD

Background

Phosphorylation of p38 (p-p38) has been reported in kidney injury models, and is known to induce cellular senescence in vitro. However, the role of p-p38 in kidney injury in vivo has not yet been fully elucidated.

Methods

We established transgenic mice (PT-MKK6EE mice) and cell lines (MKK6EE HK-2) that can induce doxycycline (Dox)-induced p38 phosphorylation in proximal tubular cells (PTCs). The contribution of p-p38 in the induction of cellular senescence and fibrosis was examined in these mice and cell lines.

Results

In wild-type mice, p-p38 expression was observed in injured PTCs in ischemia-reperfusion (IR) injury, with a concomitant suppression of Ki67 expression. In IR injury model induced in PT-MKK6EE mice, in which p-p38 was constitutively induced in PTCs, Ki67-positive PTCs were significantly reduced, suggesting a potential association between p-p38 and cell cycle arrest in vivo. PTCs of PT-MKK6EE mice exhibited lysosomal accumulation and nuclear enlargement, along with the upregulation of senescence-associated genes, indicating that p-p38 induces cellular senescence in vivo. Moreover, PTCs displaying these senescent characteristics were positive for VCAM1, a marker of failed repair PTCs. Additionally, kidney fibrosis was observed around VCAM1-positive PTCs, implying that senescent cells induced by persistent p38 phosphorylation contributed to chronic kidney disease (CKD) progression. To elucidate the molecular basis of these phenotypes, MKK6EE HK-2 were used. Dox treatment, which induces p-p38 expression, resulted in the accumulation of lysosomal proteins, nuclear enlargement, decreased expression of Cyclin D1, and increased expression of p21 and p27, along with the reduction of Skp2, an E3 ligase of p21 and p27. Furthermore, RNA sequencing analysis of Dox-treated MKK6EE HK-2 cells revealed upregulation of senescence-associated genes.

Conclusion

p-p38 induces G0 arrest through the accumulation of p21 and p27 via a decrease in Skp2. Additionally, persistent p-p38 leads to cellular senescence, both in vitro and in vivo. Furthermore, senescent PTCs induced by constitutive phosphorylation of p38 constitute VCAM-positive failed repair PTCs and contribute to CKD progression.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025ws19vrbv