Mechanisms of Si-Wu Decoction in the treatment of ulcerative colitis revealed by network pharmacology and experimental verification.

ETHNOPHARMACOLOGICAL RELEVANCE: Si-Wu Decoction (SWD) is a traditional Chinese medicine decoction. SWD is commonly used to treat blood deficiency syndrome. It is also used to treat some ulcerative colitis (UC) patients now, but the mechanism of action remains unclear. AIM OF THE STUDY: This study explored the efficacy and mechanism of action of SWD in treating UC based on network pharmacology and related experimental validation. MATERIALS AND METHODS: Several databases were used to screen SWD for major active ingredients, targets of the ingredients, and UC disease genes. Cytoscape 3.8.2 software was used for topological analysis to construct the drug-compound-disease gene-target relationship network. The String database platform was used to construct the target protein interaction network. The DAVID (Database for Annotation, Visualization and Integrated Discovery) database was used to perform the GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis for the key targets. DSS (Dextran Sulfate Sodium)-induced UC mouse model was used to evaluate the in-vivo activity of SWD. Western Blot analysis and quantitative polymerase chain reaction were performed to verify the targets in the related pathways. RESULTS: Network pharmacology revealed that the SWD targeted pathway network involved 12 core targets and 15 major pathways. SWD may play a part by targeting key targets such as nuclear factor-kappaB (NF-κB), Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) pathway, and several mitogenic pathways. We showed that SWD largely restored the colorectal structure in UC model mice. Compared to the model group, the SWD group showed reduced infiltration of inflammatory cells. SWD significantly decreased the mRNA levels of IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor-alpha), IL-1b (Interleukin-1beta) and other pro-inflammatory factors. Western Blot results showed that SWD concentration-dependently inhibited STAT3 and NF-κB activation in DSS-treated colon tissue. CONCLUSION: Our findings suggest that SWD treats UC by inhibiting STAT3 and NF-κB signaling pathways, reducing the expression of inflammatory cytokines, and improving epithelial repair in experimental colitis, thus shedding light on the mechanisms by which SWD exerts its effects on UC.

c-Abl regulates gastrointestinal muscularis propria homeostasis via ERKs.

The gastrointestinal tract is responsible for food digestion and absorption. The muscularis propria propels the foodstuff through the GI tract and defects in intestine motility may cause obstruction disorders. Our present genetic studies identified non-receptor tyrosine kinase c-Abl as an important regulator of the muscularis propria homeostasis and a risk factor for rectal prolapse. Mouse deficient for c-Abl showed defects in the muscularis propria of gastrointestinal tract and older c-Abl -/- mice developed megaesophagus and rectal prolapse. Inhibition of c-Abl with imatinib mesylate, an anti-CML drug, or ablation of c-Abl using Prx1-Cre, which marks smooth muscle cells, recapitulated most of the muscularis propria phenotypes. The pathogenesis of rectal prolapse was attributable to overproliferation of smooth muscle cells, which was caused by enhanced ERK1/2 activation. Administration of ERK inhibitor U0126 impeded the development of rectal prolapse in c-Abl deficient mice. These results reveal a role for c-Abl-regulated smooth muscle proliferation in the pathogenesis of rectal prolapse, and imply that long-term use of imatinib mesylate may cause gastrointestinal problems in patients while ERK inhibitor may be effective in treating rectal prolapse.

p38α MAPK regulates proliferation and differentiation of osteoclast progenitors and bone remodeling in an aging-dependent manner.

Bone mass is determined by the balance between bone formation, carried out by mesenchymal stem cell-derived osteoblasts, and bone resorption, carried out by monocyte-derived osteoclasts. Here we investigated the potential roles of p38 MAPKs, which are activated by growth factors and cytokines including RANKL and BMPs, in osteoclastogenesis and bone resorption by ablating p38α MAPK in LysM+monocytes. p38α deficiency promoted monocyte proliferation but regulated monocyte osteoclastic differentiation in a cell-density dependent manner, with proliferating p38α-/- cultures showing increased differentiation. While young mutant mice showed minor increase in bone mass, 6-month-old mutant mice developed osteoporosis, associated with an increase in osteoclastogenesis and bone resorption and an increase in the pool of monocytes. Moreover, monocyte-specific p38α ablation resulted in a decrease in bone formation and the number of bone marrow mesenchymal stem/stromal cells, likely due to decreased expression of PDGF-AA and BMP2. The expression of PDGF-AA and BMP2 was positively regulated by the p38 MAPK-Creb axis in osteoclasts, with the promoters of PDGF-AA and BMP2 having Creb binding sites. These findings uncovered the molecular mechanisms by which p38α MAPK regulates osteoclastogenesis and coordinates osteoclastogenesis and osteoblastogenesis.

p38α MAPK Regulates Lineage Commitment and OPG Synthesis of Bone Marrow Stromal Cells to Prevent Bone Loss under Physiological and Pathological Conditions.

Bone marrow-derived mesenchymal stromal cells (BM-MSCs) are capable of differentiating into osteoblasts, chondrocytes, and adipocytes. Skewed differentiation of BM-MSCs contributes to the pathogenesis of osteoporosis. Yet how BM-MSC lineage commitment is regulated remains unclear. We show that ablation of p38α in Prx1+ BM-MSCs produced osteoporotic phenotypes, growth plate defects, and increased bone marrow fat, secondary to biased BM-MSC differentiation from osteoblast/chondrocyte to adipocyte and increased osteoclastogenesis and bone resorption. p38α regulates BM-MSC osteogenic commitment through TAK1-NF-κB signaling and osteoclastogenesis through osteoprotegerin (OPG) production by BM-MSCs. Estrogen activates p38α to maintain OPG expression in BM-MSCs to preserve the bone. Ablation of p38α in BM-MSCs positive for Dermo1, a later BM-MSC marker, only affected osteogenic differentiation. Thus, p38α mitogen-activated protein kinase (MAPK) in Prx1+ BM-MSCs acts to preserve the bone by promoting osteogenic lineage commitment and sustaining OPG production. This study thus unravels previously unidentified roles for p38α MAPK in skeletal development and bone remodeling.