SPAK Deficiency Attenuates Chemotherapy-Induced Intestinal Mucositis.

Tien-Yu Huang,Yu-Lueng Shih,Tsai-Yuan Hsieh,Jung-Chun Lin,Ming-Hong Lin,Wei-Kuo Chang,Sung-Sen Yang,Peng-Jen Chen,Ching-Len Liao,Hsuan-Hwai Lin

doi:10.3389/fonc.2021.733555

Abstract

IntroductionSte20-related protein proline/alanine-rich kinase (SPAK) affects cell proliferation, differentiation, and transformation, and sodium and chloride transport in the gut. However, its role in gut injury pathogenesis is unclear.ObjectiveWe determined the role of SPAK in chemotherapy-induced intestinal mucositis using in vivo and in vitro models.MethodsUsing SPAK-knockout (KO) mice, we evaluated the severity of intestinal mucositis induced by 5-fluorouracil (5-FU) by assessing body weight loss, histological changes in the intestinal mucosa, length of villi in the small intestine, pro-inflammatory cytokine levels, proliferative indices, and apoptotic indices. We also evaluated changes in gut permeability and tight junction-associated protein expression. Changes in cell permeability, proliferation, and apoptosis were assessed in SPAK siRNA-transfected 5FU-treated IEC-6 cells.Results5-FU-treated SPAK-KO mice exhibited milder intestinal mucositis, reduced pro-inflammatory cytokine expression, increased villus length, good maintenance of proliferative indices of villus cells, decreased apoptotic index of enterocytes, reduced gut permeability, and restoration of tight junction protein expression (vs. 5-FU-treated wild-type mice). Under in vitro conditions, siRNA-mediated SPAK-knockdown in IEC-6 cells decreased cell permeability and maintained homeostasis following 5-FU treatment.ConclusionSPAK deficiency attenuated chemotherapy-induced intestinal mucositis by modulating gut permeability and tight junction-associated protein expression and maintaining gut homeostasis in murine small intestinal tissues following gut injury. The expression of SPAK may influence the pathogenesis of chemotherapy-induced intestinal mucositis.

Highlights

Ste20-related protein proline/alanine-rich kinase (SPAK) affects cell proliferation, differentiation, and transformation, and sodium and chloride transport in the gut
Intestinal mucositis was induced in mice (SPAK-KO and WT mice, 6–8 weeks of age, male) via intraperitoneal injection of 5-FU (30 mg/kg/day; 10 ml/kg/per injection; Sigma Chemicals) on days 0–4 of the study duration
SPAK deficiency restored the length of the villi and preserved the architecture of the intestinal mucosa in mice with 5-FUinduced intestinal mucositis compared with those in WT mice (Figure 1C and Supplementary Figure 1)

Summary

Introduction

Ste20-related protein proline/alanine-rich kinase (SPAK) affects cell proliferation, differentiation, and transformation, and sodium and chloride transport in the gut. Its role in gut injury pathogenesis is unclear. Chemotherapy-induced intestinal mucositis is a major cause of morbidity and mortality in patients with cancer [1], resulting in severe diarrhea, malabsorption, infection, and reduced chemotherapeutic efficacy. Marked diarrhea develops in approximately 50%–80% of patients who are administered 5FU or other chemotherapeutic agents [3]. Chemotherapyinduced intestinal mucositis is characterized by a decrease in the villus length, an increase in mucosal permeability, and disruption of crypt cell homeostasis [4,5,6]. Mucositis results from direct chemotherapy-induced cytotoxicity and abnormal inflammatory processes [7]. Known strategies for attenuating chemotherapy-induced intestinal damage have been primarily ineffective [3], and intestinal tissue protection is typically neglected during chemotherapy [8]

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Discussion

Conclusion