The effective clearance of apoptotic cells is essential for maintaining central nervous system (CNS) homeostasis and restoring homeostasis after injury. In most cases of physiological apoptotic cell death, efferocytosis prevents inflammation and other pathological conditions. When apoptotic cells are not effectively cleared, destruction of the integrity of the apoptotic cell membrane integrity, leakage of intracellular contents, and secondary necrosis may occur. Efferocytosis is the mechanism by which efferocytes quickly remove apoptotic cells from tissues before they undergo secondary necrosis. Cells with efferocytosis functions, mainly microglia, help to eliminate apoptotic cells from the CNS. Here, we discuss the impacts of efferocytosis on homeostasis, the mechanism of efferocytosis, the associations of efferocytosis failure and CNS diseases, and the current clinical applications of efferocytosis. We also identify efferocytosis as a novel potential target for exploring the causes and treatments of CNS diseases.

Redundancy of multinucleated mature osteoclasts, which results from the excessive fusion of mononucleated preosteoclasts (pOCs), leads to osteolytic diseases such as osteoporosis. Unfortunately, the currently available clinical drugs completely inhibit osteoclasts, thus interfering with normal physiological bone turnover. pOC-specific regulation may be more suitable for maintaining bone homeostasis. Here, circBBS9, a previously unidentified circular RNA, was found to exert regulatory effects via the circBBS9/miR-423-3p/Traf6 axis in pOCs. To overcome the long-standing challenge of spatiotemporal RNA delivery to cells, we constructed biomimetic nanoparticles to achieve the pOC-specific targeted delivery of circBBS9. pOC membranes (POCMs) were extracted to camouflage cationic polymer for RNA interference with circBBS9 (POCM-NPs@siRNA/shRNA ^circBBS9 ). POCM-NPs endowed the nanocarriers with improved stability, accurate pOC targeting, fusogenic uptake, and reactive oxygen species–responsive release. In summary, our findings may provide an alternative strategy for multinucleated cell–related diseases that involves restriction of mononucleated cell multinucleation through a spatiotemporally selective delivery system.

The incidence of osteoporosis, which is primarily characterized by plethoric osteoclast (OC) formation and severe bone loss, has increased in recent years. Millions of people worldwide, especially postmenopausal women, suffer from osteoporosis. The drugs commonly used to treat osteoporosis still exist many disadvantages, but natural extracts provide options for the treatment of osteoporosis. Therefore, the identification of cost-effective natural compounds is important. Patchouli alcohol (PA), a natural compound extracted from Pogostemon cablin that exerts anti-inflammatory effects, is used as a treatment for gastroenteritis. However, no research on the use of Patchouli alcohol in osteoporosis has been reported. We found that PA dose-dependently inhibited the receptor activator of nuclear factor kappa-B ligand (RANKL)-induced formation and function of OCs without cytotoxicity. Furthermore, these inhibitory effects were reflected in the significant effect of PA on the NF-κB signaling pathway, as PA suppressed the transcription factors NFATc1 and c-Fos. We also determined that PA activated expression of the nuclear receptor pregnane X receptor (PXR) and promoted the PXR/Toll-like receptor 4 (TLR4) axis to inhibit the nuclear import of NF-κB (p50 and p65). Additionally, PA exerted therapeutic effects against osteoporosis in ovariectomized (OVX) mice, supporting the use of PA as a treatment for osteoporosis in the future.

The cell membrane structure is closely related to the occurrence and progression of many metabolic bone diseases observed in the clinic and is an important target to the development of therapeutic strategies for these diseases. Strong experimental evidence supports the existence of membrane microdomains in osteoclasts (OCs). However, the potential membrane microdomains and the crucial mechanisms underlying their roles in OCs have not been fully characterized. Membrane microdomain components, such as scaffolding proteins and the actin cytoskeleton, as well as the roles of individual membrane proteins, need to be elucidated. In this review, we discuss the compositions and critical functions of membrane microdomains that determine the biological behavior of OCs through the three main stages of the OC life cycle.

Background: Spinal cord injury (SCI) remains a profound medical challenge, with limited therapeutic options available. Studies focusing on individual molecular markers have limitations in addressing the complex disease process. Methods: This study utilizes RNA-sequencing (RNA-seq) to investigate the differentially expressed genes (DEGs) in spinal cord tissue from a rat SCI model at 1 and 21 days post-injury (dpi). After data processing and analysis, a series of biological pathway enrichment analyses were performed using online tools DAVID and GSEA. Interactions among the enriched genes were studied using Cytoscape software to visualize protein–protein interaction networks. Results: Our analysis identified 595 DEGs, with 399 genes significantly upregulated and 196 significantly downregulated at both time points. CD68 was the most upregulated gene at 21 dpi, with a significant fold change at 1 dpi. Conversely, MPZ was the most downregulated gene. Key immune response processes, including tumor necrosis factor (TNF) production, phagocytosis, and complement cascades, as well as systemic lupus erythematosus (SLE)-associated pathways, were enriched in the upregulated group. The enriched pathways in the downregulated group were related to the myelin sheath and neuronal synapse. Genes of interest from the most significantly downregulated DEGs were SCD, DHCR24, PRX, HHIP, and ZDHHC22. Upregulation of Fc-γ receptor genes, including FCGR2B and FCGR2A, points to potential autoimmune mechanisms. Conclusions: Our findings highlight complex immune and autoimmune responses that contribute to ongoing inflammation and tissue damage post-SCI, underscoring new avenues for therapeutic interventions targeting these molecular processes.

Mitochondrial dysfunction occurs in macrophages with efferocytosis defects, which hinders recovery from tissue injury. Targeting intercellular mitochondrial transfer is a promising therapy for augmenting cellular therapy. Here, this work elucidates the stress resistance capabilities of mitochondria in anucleate platelets and shows that platelets transfer mitochondria to macrophages under cellular stress, which restores impaired efferocytosis. This work devises a delivery system in which platelets are loaded with cationic polymers (NPs) for PPARγ overexpression and conjugated to macrophages (M‐P‐NPs@PPARγ). In this system, activated platelets induce mitochondrial transfer and release NPs into macrophages, increasing ATP production and maintaining lipid homeostasis. As a proof‐of‐concept, in representative efferocytosis‐deficit central nervous system disease spinal cord injury model, impaired efferocytosis is reversed by M‐P‐NP@PPARγ, resulting in neural regeneration and remyelination and ultimately promoting motor function recovery. In summary, this work has developed a strategy combining mitochondria and gene delivery to restore macrophage efferocytosis postinjury by regulating energy and lipid metabolism.