RhoB, a member of the Rho family GTPases, shares high sequence similarity with RhoA and RhoC but has distinct functions [3]. It is involved in various cellular processes such as actin organization, cell migration, membrane trafficking, cell proliferation, DNA-repair, and apoptosis [3]. RhoB interfaces with signaling pathways like EGFR, Ras, and PI3K/Akt to modulate cellular structure and function [4].

In colitis, RhoB shows increased expression in ulcerative colitis (UC) patients and DSS-induced colitis mice. RhoB+/- and RhoB-/- mice develop milder DSS-induced colitis, with increased goblet cell numbers and IEC proliferation. Decreased RhoB promotes goblet cell differentiation and epithelial regeneration via inhibiting Wnt signaling and activating p38 MAPK signaling. Also, these mice have increased SCFA-producing bacteria, SCFA concentrations, and upregulated SCFA receptor expression, suggesting RhoB's potential as a biomarker and treatment target for UC [1]. In pancreatic cancer, RhoB is down-regulated in gemcitabine-resistant cells and is a downstream target of hsa-miR-3178. RhoB can reverse hsa-miR-3178-mediated gemcitabine resistance, indicating its role in chemotherapy resistance [2].

In summary, RhoB plays diverse roles in multiple biological processes and diseases. Gene knockout mouse models have revealed its significance in colitis and pancreatic cancer, highlighting its potential as a biomarker and therapeutic target in these disease areas.

References:

1. Yang, Jianming, Pei, Geng, Sun, Xuan, Yao, Zhi, Wang, Quan. 2022. RhoB affects colitis through modulating cell signaling and intestinal microbiome. In Microbiome, 10, 149. doi:10.1186/s40168-022-01347-3. https://pubmed.ncbi.nlm.nih.gov/36114582/

2. Gu, Jianyou, Huang, Wenjie, Wang, Xianxing, Wang, Huaizhi, Fan, Yingfang. 2022. Hsa-miR-3178/RhoB/PI3K/Akt, a novel signaling pathway regulates ABC transporters to reverse gemcitabine resistance in pancreatic cancer. In Molecular cancer, 21, 112. doi:10.1186/s12943-022-01587-9. https://pubmed.ncbi.nlm.nih.gov/35538494/

3. Vega, Francisco M, Ridley, Anne J. 2016. The RhoB small GTPase in physiology and disease. In Small GTPases, 9, 384-393. doi:10.1080/21541248.2016.1253528. https://pubmed.ncbi.nlm.nih.gov/27875099/

4. Gutierrez, Eutiquio, Cahatol, Ian, Bailey, Cedric A R, Dennis, Phillip, Zhang, Chunyu. 2019. Regulation of RhoB Gene Expression during Tumorigenesis and Aging Process and Its Potential Applications in These Processes. In Cancers, 11, . doi:10.3390/cancers11060818. https://pubmed.ncbi.nlm.nih.gov/31200451/