Annexin A5 Derived from Cell-free Fat Extract Attenuates Osteoarthritis via Macrophage Regulation.

Osteoarthritis (OA) is a challenging degenerative joint disease to manage. Previous research has indicated that cell-free fat extract (CEFFE) may hold potential for OA treatment. This study investigated the role of Annexin A5 (AnxA5) within CEFFE in regulating macrophage polarization and protecting chondrocytes. In vitro experiments demonstrated that AnxA5 effectively inhibited M1 macrophage polarization by facilitating toll-like receptor (TLR) 4 internalization and lysosomal degradation through calcium-dependent endocytosis. This process decreased TLR4 expression, suppressed pro-inflammatory mediator release, and reduced the production of reactive oxygen species. Furthermore, AnxA5 displayed protective effects against chondrocyte necrosis and apoptosis. In vivo, studies revealed that intra-articular administration of AnxA5 ameliorated pain symptoms in a monosodium iodoacetate-induced osteoarthritis rat model. Histological analyses indicated a decrease in synovial inflammation and mitigation of cartilage damage following AnxA5 treatment. These results underscored the potential of AnxA5 as a therapeutic option for OA due to its capacity to regulate macrophage polarization and maintain chondrocyte viability. Further investigation into the specific mechanisms and clinical applications of AnxA5 may help improve the management of OA.

METTL3 Promotes Nucleus Pulposus Cell Senescence in Intervertebral Disc Degeneration by Regulating TLR2 m6A Methylation and Gut Microbiota.

BACKGROUND: Nucleus pulposus cell (NPC) senescence in intervertebral disc (IVD) tissue is the major pathological cause of intervertebral disc degeneration (IDD). N6-methyladenosine (m6A) methylation and gut microbiota play important roles in the progression of IDD. This study investigated whether methyltransferase-like 3 (METTL3) regulates TLR2 m6A modification and gut microbiota to influence NPC senescence. METHODS: An IDD rat model was established by lumbar IVD puncture and NPCs were challenged with IL-1ß to mimic IVD injury. IDD rats and IL-1ß-exposed NPCs were treated with METTL3-interfering lentivirus and the TLR2 agonist Pam3CSK4. Compositional changes in the rat gut microbiota were analyzed and fecal microbiota transplantation procedures were used. NPC senescence, cell cycle, and the expression of senescence-associated secretory phenotype (SASP) factors were assessed. The m6A enrichment of TLR2 and the binding of IGF2BP1 to TLR2 mRNA were examined. RESULTS: METTL3 and TLR2 were highly expressed in IDD rats. METTL3 silencing attenuated senescent phenotypes and reduced secretion of SASP factors. Pam3CSK4 reversed the beneficial effects of METTL3 silencing on NPC senescence and IVD injury. METTL3 stabilized TLR2 mRNA in an IGF2BP1-dependent manner. METTL3 silencing restored specific gut microbiota levels in IDD rats, which was further reversed by administration of Pam3CSK4. Fecal microbiota from METTL3 silenced IDD rats altered the pathological phenotypes of IDD rats. CONCLUSIONS: These results demonstrate the beneficial effects of METTL3 silencing on NPC senescence and amelioration of IVD injury, involving modulation of TLR2 m6A modification and gut microbiota. These findings support METTL3 silencing as a potential therapeutic target for IDD.

Senescent-like macrophages mediate angiogenesis for endplate sclerosis via IL-10 secretion in male mice.

Endplate sclerosis is a notable aspect of spine degeneration or aging, but the mechanisms remain unclear. Here, we report that senescent macrophages accumulate in the sclerotic endplates of lumbar spine instability (LSI) or aging male mouse model. Specifically, knockout of cdkn2a (p16) in macrophages abrogates LSI or aging-induced angiogenesis and sclerosis in the endplates. Furthermore, both in vivo and in vitro studies indicate that IL-10 is the primary elevated cytokine of senescence-related secretory phenotype (SASP). Mechanistically, IL-10 increases pSTAT3 in endothelial cells, leading to pSTAT3 directly binding to the promoters of Vegfa, Mmp2, and Pdgfb to encourage their production, resulting in angiogenesis. This study provides information on understanding the link between immune senescence and endplate sclerosis, which might be useful for therapeutic approaches.

Novel transgenic pigs with enhanced growth and reduced environmental impact.

In pig production, inefficient feed digestion causes excessive nutrients such as phosphorus and nitrogen to be released to the environment. To address the issue of environmental emissions, we established transgenic pigs harboring a single-copy quad-cistronic transgene and simultaneously expressing three microbial enzymes, ß-glucanase, xylanase, and phytase in the salivary glands. All the transgenic enzymes were successfully expressed, and the digestion of non-starch polysaccharides (NSPs) and phytate in the feedstuff was enhanced. Fecal nitrogen and phosphorus outputs in the transgenic pigs were reduced by 23.2-45.8%, and growth rate improved by 23.0% (gilts) and 24.4% (boars) compared with that of age-matched wild-type littermates under the same dietary treatment. The transgenic pigs showed an 11.5-14.5% improvement in feed conversion rate compared with the wild-type pigs. These findings indicate that the transgenic pigs are promising resources for improving feed efficiency and reducing environmental impact.