TGF-β signaling is a vital regulator for maintaining articular cartilage homeostasis. Runx transcription factors, downstream targets of TGF-β signaling, have been studied in the context of osteoarthritis (OA). Although Runx partner core binding factor β (Cbfβ) is known to play a pivotal role in chondrocyte and osteoblast differentiation, the role of Cbfβ in maintaining articular cartilage integrity remains obscure. This study investigated Cbfβ as a novel anabolic modulator of TGF-β signaling and determined its role in articular cartilage homeostasis. Cbfβ significantly decreased in aged mouse articular cartilage and human OA cartilage. Articular chondrocyte-specific Cbfb-deficient mice (Cbfb^△ac/△ac) exhibited early cartilage degeneration at 20 weeks of age and developed OA at 12 months. Cbfb^△ac/△ac mice showed enhanced OA progression under the surgically induced OA model in mice. Mechanistically, forced expression of Cbfβ rescued Type II collagen (Col2α1) and Runx1 expression in Cbfβ-deficient chondrocytes. TGF-β1-mediated Col2α1 expression failed despite the p-Smad3 activation under TGF-β1 treatment in Cbfβ-deficient chondrocytes. Cbfβ protected Runx1 from proteasomal degradation through Cbfβ/Runx1 complex formation. These results indicate that Cbfβ is a novel anabolic regulator for cartilage homeostasis, suggesting that Cbfβ could protect OA development by maintaining the integrity of the TGF-β signaling pathway in articular cartilage.

Pulmonary fibrosis (PF) is a terminal‐stage lung change in interstitial lung disease. It is characterized by proliferation of fibroblasts and deposition of a large amount of extracellular matrix, accompanied by inflammatory damage and structural destruction, caused by various reasons. The prognosis of PF is poor, and the average survival time after diagnosis is 2.5–3.5 years. The pathogenesis of PF is not yet fully understood. Its main mechanisms are diverse and include damage to alveolar epithelial cells, aggregation and activation of inflammatory cells and chemokines, proliferation of fibroblasts, transformation of myofibroblasts, production and deposition of large amounts of collagen, autophagy, epithelial–mesenchymal transition (EMT), mitochondrial quality‐control disorders, microRNA, and circular RNA. The diagnosis of PF is mainly based on the comprehensive evaluation of clinical manifestations, imaging characteristics, and histopathological examination. Medical and family history to determine all potential causes of PF. For PF of unknown etiology, one can refer to the Official Clinical Practice Guideline of idiopathic pulmonary fibrosis (IPF) for definitive diagnosis. In terms of treatment, modern medications such as pirfenidone and nintedanib can inhibit the progression of PF to some extent and improve lung function. However, there is no drug that can significantly improve PF, except for lung transplantation. In addition, many patients are forced to stop taking medication due to adverse reactions in clinical practice. Therefore, to better control the progression of disease, some new drugs have been developed based on the pathogenesis of PF. However, there is still controversy over their efficacy and widespread clinical application in PF, and the evidence is limited. The results of in vitro and in vivo experiments, as well as randomized clinical trials, indicate that traditional Chinese medicine (TCM) can improve PF by intervening in multiple pathways and targets. This study combines the pathogenesis and diagnosis of PF, focusing on the intervention mechanism and targets of TCM in the treatment of PF, so as to provide more options for clinical treatment and provide scientific basis for a new approach to better management of PF.

In our previous study, 4-hexylresorcinol (4HR) increased the expression level of vascular endothelial growth factor in human umbilical vein endothelial cells (HUVECs) via the transforming growth factor-β1 (TGF-β1)-mediated pathway. Endoplasmic reticulum (ER) and mitochondrial stress is a positive regulator of cellular differentiation. As TGF-β1 is a master regulator for cellular differentiation, 4HR treatment may increase TGF-β1 expression via ER stress. In this study, HUVECs were treated using 4HR (1–100 μM) for 24 h. The 4HR treatment increased ER stress-associated markers and mitochondrial stress. Increased TGF-β1 expression by 4HR administration was alleviated by tauroursodeoxycholate (ER stress inhibitor) treatment. Combining these activities with the elevated acetylation level of histone 3 (H3) by 4HR treatment, TGF-β1 expression was increased in HUVECs. Overall, 4HR increased TGF-β1 expression through upregulation of the stress response of ER as well as H3 acetylation in HUVECs.

Background: Osteoporosis is a bone remodeling disease characterized by an imbalance between bone formation and resorption, leading to bone fragility. Current treatments focus on bone resorption suppression but often have adverse effects. This study aimed to explore the potential of sericin, a silkworm-derived protein, as a dual-action therapeutic agent that enhances bone formation through its component L-serine and inhibits bone resorption via D-serine, which is derived from L-serine by the action of serine racemase. Methods: Cellular experiments were conducted to evaluate the effects of L-serine on osteoblast differentiation and D-serine on osteoclast inhibition. Serum levels of D-serine were measured following sericin administration in an osteoporosis animal model. μ-CT analysis assessed trabecular and cortical bone quality, and bone-related protein expression was analyzed using immunoprecipitation-based high-performance liquid chromatography (IP-HPLC). Results: L-serine significantly upregulated osteogenic markers, including alkaline phosphatase (ALP), Runx2, osterix, and Col1a1, in osteoblasts (p < 0.05). D-serine inhibited osteoclast activation by suppressing cathepsin K expression (p < 0.001). Sericin feeding elevated serum D-serine levels (p < 0.001) and upregulated bone-related proteins such as BMP-2, osterix, and Runx2. Micro-computed tomography (μ-CT) analysis revealed significant improvements in trabecular bone parameters in the OVX-sericin group, including increased trabecular bone volume (Tb.BV/TV; p < 0.05) and reduced trabecular separation (Tb.Sp; p < 0.05), compared to the OVX and OVX-amino acid groups. Cortical bone parameters, including cortical bone volume (Ct.BV/TV) and cortical area (Ct.Ar), did not significantly differ among OVX groups, but all were lower than in the sham group (p < 0.05). Conclusions: This study demonstrates that sericin modulates bone metabolism by enhancing osteoblast activity through L-serine and inhibiting osteoclastogenesis via D-serine. Sericin supplementation improved trabecular bone mass in an osteoporosis model, highlighting its potential for bone health.

Hypoxic environment is essential for chondrocyte maturation and longitudinal bone growth. Although hypoxia‐inducible factor 1 alpha (Hif‐1α) has been known as a key player for chondrocyte survival and function, the function of Hif‐2α in cartilage is mechanistically and clinically relevant but remains unknown. Here we demonstrated that Hif‐2α was a novel inhibitor of chondrocyte maturation through downregulation of Runx2 stability. Mechanistically, Hif‐2α binding to Runx2 inhibited chondrocyte maturation by Runx2 degradation through disrupting Runx2/Cbfβ complex formation. The Hif‐2α‐mediated‐Runx2 degradation could be rescued by Cbfβ transfection due to the increase of Runx2/Cbfβ complex formation. Consistently, mesenchymal cells derived from Hif‐2α heterozygous mice were more rapidly differentiated into hypertrophic chondrocytes than those of wild‐type mice in a micromass culture system. Collectively, these findings demonstrate that Hif‐2α is a novel inhibitor for chondrocyte maturation by disrupting Runx2/Cbfβ complex formation and consequential regulatory activity.