Role of Aberrantly Activated Lysophosphatidic Acid Receptor 1 Signaling Mediated Inflammation in Renal Aging.

Yongjie Jin,Tae Hyun Ban,Chul Woo Yang,Ji Hee Lim,Hyung Duk Kim,Cheol Whee Park,Eun Nim Kim,Bum Soon Choi

doi:10.3390/cells10102580

Abstract

The increasing load of senescent cells is a source of aging, and chronic inflammation plays a pivotal role in cellular senescence. In addition, senescent renal tubular epithelial cells are closely associated with renal aging. Lysophosphatidic acid (LPA) is a bioactive lipid mainly produced by the catalytic action of autotaxin (ATX), and its ligation to LPA receptor-1 (LPAR1) is associated with chronic inflammation and renal fibrosis; however, its role in renal aging is unclear. Male 2-, 12-, and 24-month-old C57BL/6 mice and Human renal proximal tubular epithelial cells (HRPTEpiC) were used in the present study. DNA damage and oxidative stress-induced senescence were simulated using doxorubicin (DOXO) and H2O2, respectively. The aged kidney showed decreased renal function, increased fractional mesangial area, and tubulointerstitial fibrosis. Both aged kidney and senescent cells showed increased levels of LPAR1, Nuclear factor κB (NF-κB), and inflammatory cytokines. In addition, LPAR1-knockdown reduced NF-κB and subsequent inflammatory cytokine induction, and NF-κB-knockdown resulted in decreased LPAR1 expression. Our study revealed a positive feedback loop between LPAR1 and NF-κB, which reinforces the role of inflammatory response, suggesting that blocking of aberrantly activated LPAR1 may reduce excessive inflammation, thereby providing a new possible therapeutic strategy to attenuate renal aging.

Highlights

The progressive loss of physiological integrity is a characteristic feature of aging, which leads to impaired function and increased mortality [1]
Histological examination showed that the fractional mesangial area was significantly expanded in the 24 M group compared with the 2 M and
The results showed that knockdown of LPA receptor-1 (LPAR1) (Figure 7A,B) markedly reduced Nuclear factor κB (NF-κB)

Summary

Introduction

The progressive loss of physiological integrity is a characteristic feature of aging, which leads to impaired function and increased mortality [1]. In China, the prevalence of chronic kidney disease (CKD) in men and women is parallel with age, increasing from 5.1% and 7.4% in those aged 18–39 years, to 18.5% and 24.2%. The accumulation of senescent cells with age is considered an important promoter of the aging process [12]. During aging, secreted inflammatory cytokines reinforce the senescent phenotype through several positive feedback loops [16]. They produce an inflammatory cascade that affects the surrounding cells. The altered intracellular and intercellular communication results in an aberrant accumulation of senescent cells, which causes or exacerbates aging and age-related diseases [13,15,17].

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Discussion

Conclusion