The radix achyranthes bidentata regulates BMSCs-derived chondrogenic differentiation by modulating Rab39a and activating SOX9 and RHOA/RACK1 signaling



Osteoarthritis (OA) is a global joint disease and a leading cause of disability. Radix achyranthes bidentata extract (ABE) has been extensively used to treat OA; however, the molecular basis remains unclear.



To investigate the effects of ABE on the chondrogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) and associated mechanisms.



BMSCs were obtained from the femur and tibia of rabbits and identified by staining CD44 and CD90. ABE-containing rabbit serum was prepared and administered to BMSCs. RNA samples were collected and subjected to transcriptome sequencing. GO, and KEGG enrichment analysis of differential expression genes was analyzed. iTRAQ labeling and LC-MS/MS-based proteomic analysis were conducted. Quantitative real-time PCR (RT-PCR) and Western blotting analysis were performed to determine gene transcription and protein expression.



ABE was proven to facilitate the proliferation and differentiation of BMSCs, as a promising attractive cell source for cartilage tissue repair. By integrating transcriptome and proteome data, we have dissected the global molecular signature of BMSCs upon ABE treatment and identified the energy metabolic pathway and ‘infection’ expression patterns as the key molecular signatures targeted by ABE. Rab39b was commonly identified as a novel effector protein and dramatically enriched in both RNA-seq and proteome data sets. Genetic loss of Rab39b in BMSCs reduced proliferation and chondrogenic differentiation. Mechanically, Rab39b increased cartilaginous tissue biomarkers, such as collagen alpha-1 (X) chain (COL10A1) and collagen alpha-1 (II) chain (COL2A1), by activating SOX9 and RHOA/RACK1 signaling.



The extract of Radix achyranthes bidentata could regulate BMSCs-derived chondrogenic differentiation by modulating Rab39b and activating the SOX9 and RHOA/RACK1 signaling pathways. This study uncovered the global molecular characteristics of the BMSC-derived chondrogenic differentiation, which would provide the molecular basis for developing novel cellular targets for ABE treatment against OA.
