Alzheimer’s disease (AD) is characterized by progressive neurodegeneration, neuroinflammation, and systemic comorbidities, yet disease-modifying therapies remain elusive. Here, we show that partial epigenetic reprogramming via brain-restricted expression of Oct4, Sox2, and Klf4 (OSK) restores neuronal and neuroimmune homeostasis without loss of cellular identity. In APP/PS1 mice, OSK reprogramming improves cognitive performance across disease stages, reduces amyloid-β deposition, attenuates microglial activation, preserves synaptic integrity, and limits neuronal apoptosis. Mechanistically, reduced representation bisulfite sequencing reveals widespread reversal of AD-associated DNA methylation patterns, which is dependent on Tet2-mediated demethylation, establishing epigenetic rejuvenation as a key driver of functional recovery. Unexpectedly, brain-restricted OSK reprogramming also ameliorates systemic bone loss by reshaping brain-derived extracellular vesicle signaling, including modulation of miR-483-5p, thereby restoring osteogenic capacity. Together, these findings identify partial epigenetic reprogramming as a strategy to rewire neuro-immune circuits and link central nervous system rejuvenation to peripheral tissue homeostasis, providing a conceptual framework for targeting both neurodegeneration and its systemic consequences in AD.

Brain health is closely linked to bone homeostasis. Skeletal aging is characterized by inadequate bone formation and marrow adiposity, but whether the brain contributes to this imbalance remains unknown. This study shows that aged brain neurons, mainly those in the hippocampus and cerebral cortex, produce excess WD repeat and FYVE domain containing 1 (WDFY1) protein and transfer it to the bone via extracellular vesicles (EVs), leading to bone-fat imbalance and osteoporosis. Increasing brain Wdfy1 expression causes premature skeletal aging. Conversely, suppressing Wdfy1 in the whole brain, hippocampus or neurons, genetically deleting neuronal Wdfy1, and selectively inhibiting neuronal EV release all improve bone health. Mechanistically, WDFY1 binds to the retromer complex to promote the endosome-to-Golgi recycling of cathepsin D and peroxiredoxin 2, thus inhibiting osteogenesis and augmenting adipogenesis. This study identifies the role of aged brain neuronal EVs as an important messenger in triggering bone-fat imbalance by transferring WDFY1 to bone. Chen et al. identify a brain-to-bone communication axis whereby extracellular vesicles from aged brain neurons transport WDFY1 protein to distal bone, driving bone-fat imbalance and promoting osteoporosis.

Emerging evidence suggests that gut microbiota-derived signals can influence distant organs including the skeleton, yet the key microbial effectors remain elusive. Here, we identify Amuc_1473, a previously uncharacterized protein enriched in extracellular vesicles (EVs) from the commensal bacterium Akkermansia muciniphila (Akk), as a critical mediator of gut-bone communication. Amuc_1473 directly promotes osteogenesis and suppresses osteoclastogenesis by binding to negative elongation factor E (NELF-E) and ribosomal protein L26 (RPL26), regulators of transcriptional pausing and mRNA translation, respectively. Notably, Amuc_1473 levels decline in bone and circulation under diverse pro-osteoporotic conditions-including aging, estrogen deficiency, mechanical unloading, high-fat diet, smoking, alcohol, and chronic stress-paralleling reductions in Akk and its EVs. Intermittent fasting robustly restores Akk abundance, Amuc_1473 levels, and bone quality in these models, via enhanced mucin production. Our findings establish Amuc_1473 as a microbial effector that systemically regulates bone homeostasis, offering a translatable strategy to prevent or treat multifactorial osteoporosis.

Vascular calcification (VC) is a major contributor to cardiovascular morbidity and mortality, yet effective therapies are lacking. Here, we show that alternate-day intermittent fasting (IF1:1) attenuates vitamin D-induced VC in mice, whereas a 5:2 regimen is ineffective. The protective effect of IF1:1 is gut microbiota-dependent, particularly through enrichment of Akkermansia muciniphila (Akk). Microbiota-derived extracellular vesicles (EVs) function as nano-scale mediators that bypass the spatiotemporal constraints of bacterial survival to facilitate long-distance communication with host cells, providing a crucial pathway for downstream mechanistic investigation. Akk-derived EVs (Akk-EVs) are internalized by vascular smooth muscle cells (VSMCs), suppressing osteogenic differentiation and calcification in vitro and in vivo. Proteomic analysis identified B2URF3 as a highly enriched functional protein in Akk-EVs and Akk, which interacts with Aldehyde Dehydrogenase 1 Family Member B1 (ALDH1B1) to inhibit VSMC osteogenic transdifferentiation. Clinically, reduced fecal Akk abundance and lower serum B2URF3 levels were observed in patients with coronary calcification. These findings define a gut-vascular axis by which IF1:1 mitigates VC and nominate Akk-EVs and B2URF3 as potential therapeutic targets and biomarkers.

Osteoarthritis (OA) is a prevalent joint disease with a complex etiology, involving epigenetic alterations. Recent studies have suggested the potential of Oct4, Sox2 and Klf4 (OSK) in rejuvenating adult cells and facilitating tissue repair, but their specific role in OA pathophysiology and treatment remains unclear. Here we employed an adeno-associated virus (AAV) vector to achieve ectopic expression of OSK (AAV-OSK). Chondrocytes expressing OSK retained chondrocyte-specific markers with no increase in stemness-associated genes. AAV-OSK significantly preserved chondrocyte vitality in an inflammatory environment and counteracted the upregulation of osteogenic genes during OG differentiation. In OA murine models, AAV-OSK administration led to a notable improvement in cartilage integrity, a reduction in subchondral bone thickening and promoted the hyalinization of fibrocartilage. Furthermore, chondrocyte senescence and DNA methyltransferase expression were markedly diminished in the AAV-OSK group. Tet methylcytosine dioxygenase 2 was identified as a pivotal factor underlying the benefits of OSK-driven cartilage regeneration. Collectively, our study underscores that OSK expression within the knee joint modulates epigenetic alterations, mitigating OA progression and cartilage fibrosis through partial reprogramming, highlighting its therapeutic promise for comprehensive OA intervention.

Mitochondrial homeostasis plays a crucial role in the pathogenesis of osteoarthritis (OA), a chronic musculoskeletal disorder characterized by articular cartilage degeneration and chondrocyte apoptosis. However, molecular mechanisms underlying the association between mitophagy and OA remain unclear. Here, we aimed to investigate the role of the autophagy receptor protein optineurin (OPTN) in OA, and explore the effects of dietary intervention on OA symptoms and its relationship with OPTN-mediated mitophagy. Our findings showed the downregulation of OPTN in patients with OA. Using an Optn-knockout mouse model, we demonstrated that OPTN deficiency leads to impaired mitophagy, resulting in the accumulation of damaged mitochondria, increased production of reactive oxygen species, and chondrocyte apoptosis. Furthermore, fasting prevented OA progression by activating OPTN-mediated mitophagy and maintaining mitochondrial homeostasis in mice. The present study revealed a novel mechanism by which OPTN-mediated mitophagy influences chondrocytes and the OA phenotype in Optn-knockout mice, suggesting that OPTN-mediated mitophagy plays a crucial role in OA development and progression. This study provides new insights into the pathogenesis of OA and offers a potential avenue for the development of novel drugs targeting OPTN to mitigate OA progression.

Osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs) facilitated by mechanical loading is a promising therapy for disuse osteoporosis (DOP), however, it is difficult to implement mechanical loading for a majority of patients. Our study aims to identify circ-ITCH-mediated novel approach to facilitate osteogenic differentiation in DOP. A rat DOP model and human BM-MSCs under microgravity condition were generated as in vivo and in vitro models of DOP, respectively. The bone mineral density (BMD) and bone parameters were examined in rats. The histological changes of bones and mineralization were monitored by H E, Alcian blue and Alizarin red S staining. Co-IP was employed to examine the ubiquitination of HOXC10 and the interaction between HOXC10 and BRCA1. The direct associations among circ-ITCH, IGFBP2 and BRCA1 mRNA were assessed by RIP, FISH and RNA pull-down assays. Circ-ITCH was downregulated in rat model of DOP and BM-MSCs under microgravity stimulation. Circ-ITCH overexpression promoted osteogenic differentiation in BM-MSCs under microgravity condition. The altered bone parameters, such as BMD, trabecular number (Tb.N), trabecular separation (Tb.Sp), trabecular thickness (Tb.Th), and bone microstructure in DOP rats were rescued by circ-ITCH overexpression. Mechanistically, circ-ITCH enhanced the ubiquitination degradation of HOXC10 through enhancing BRCA1 mRNA stability. Circ-ITCH directly bound to IGF2BP2 protein to stabilize BRCA1 mRNA via m6A modification, thus facilitating osteogenic differentiation in BM-MSCs under microgravity condition. Circ-ITCH stabilized BRCA1 mRNA via IGF2BP2-mediated m6A modification, thereby facilitating the ubiquitination degradation of HOXC10 to promote osteogenic differentiation in DOP.

Background Pulmonary fibrosis (PF) is a progressive fibrosing interstitial pneumonia that leads to respiratory failure and other complications, which is ultimately fatal. Mesenchymal stem cells (MSCs) transplant is a promising strategy to solve this problem, while the procurement of MSCs from the patient for autotransplant remains a challenge. Methods Here, we presented olfactory mucosa mesenchymal stem cells (OM-MSCs) from mouse turbinate and determined the preventing efficacy of allotransplant for PF. We demonstrated the antiinflammation and immunomodulatory effects of OM-MSCs. Flow cytometric analysis was used to verify the effect of OM-MSCs on monocyte-derived macrophage populations in the lung. Results Administration of OM-MSCs reduces inflammation, attenuates the matrix metallopeptidase 13 (MMP13) expression level and restores the bleomycin (BLM)-induced pulmonary fibrosis by assessing the architecture of lung, collagen type I; (COL1A1), actin alpha 2, smooth muscle, aorta (ACTA2/α-SMA) and hydroxyproline. This therapeutic effect of OM-MSCs was related to the increase in the ratio of nonclassical monocytes to proinflammatory monocytes in the lung. Conclusions This study suggests that transplant of OM-MSCs represents an effective and safe treatment for PF.

Study designAnimal studiesObjectivesTo evaluate the therapeutic effect of olfactory mucosa mesenchymal stem cell (OM-MSCs) transplantation in mice with spinal cord injury (SCI) and to explore the mechanism by which OM-MSCs inhibit neuroinflammation and improve SCI.SettingXiangya Hospital, Central South University; Affiliated Hospital of Guangdong Medical University.MethodsMice (C57BL/6, female, 6-week-old) were randomly divided into sham, SCI, and SCI + OM-MSC groups. The SCI mouse model was generated using Allen's method. OM-MSCs were immediately delivered to the lateral ventricle after SCI using stereotaxic brain injections. One day prior to injury and on days 1, 5, 7, 14, 21, and 28 post-injury, the Basso Mouse Scale and Rivlin inclined plate tests were performed. Inflammation and microglial polarization were evaluated using histological staining, immunofluorescence, and qRT-PCR.ResultsOM-MSCs originating from the neuroectoderm have great potential in the management of SCI owing to their immunomodulatory effects. OM-MSCs administration improved motor function, alleviated inflammation, promoted the transformation of the M1 phenotype of microglia into the M2 phenotype, facilitated axonal regeneration, and relieved spinal cord injury in SCI mice.ConclusionsOM-MSCs reduced the level of inflammation in the spinal cord tissue, protected neurons, and repaired spinal cord injury by regulating the M1/M2 polarization of microglia.

Aging increases the risks of various diseases and the vulnerability to death. Cellular senescence is a hallmark of aging that contributes greatly to aging and aging-related diseases. This study demonstrates that extracellular vesicles from human urine-derived stem cells (USC-EVs) efficiently inhibit cellular senescence in vitro and in vivo. The intravenous injection of USC-EVs improves cognitive function, increases physical fitness and bone quality, and alleviates aging-related structural changes in different organs of senescence-accelerated mice and natural aging mice. The anti-aging effects of USC-EVs are not obviously affected by the USC donors' ages, genders, or health status. Proteomic analysis reveals that USC-EVs are enriched with plasminogen activator urokinase (PLAU) and tissue inhibitor of metalloproteinases 1 (TIMP1). These two proteins contribute importantly to the anti-senescent effects of USC-EVs associated with the inhibition of matrix metalloproteinases, cyclin-dependent kinase inhibitor 2A (P16INK4a), and cyclin-dependent kinase inhibitor 1A (P21cip1). These findings suggest a great potential of autologous USC-EVs as a promising anti-aging agent by transferring PLAU and TIMP1 proteins.

Osteoarthritis is a highly prevalent progressive joint disease that still requires an optimal therapeutic approach. Intermittent fasting is an attractive dieting strategy for improving health. Here this study shows that intermittent fasting potently relieves medial meniscus (DMM)- or natural aging-induced osteoarthritic phenotypes. Osteocytes, the most abundant bone cells, secrete excess neuropeptide Y (NPY) during osteoarthritis, and this alteration can be altered by intermittent fasting. Both NPY and the NPY-abundant culture medium of osteocytes (OCY-CM) from osteoarthritic mice possess pro-inflammatory, pro-osteoclastic, and pro-neurite outgrowth effects, while OCY-CM from the intermittent fasting-treated osteoarthritic mice fails to induce significant stimulatory effects on inflammation, osteoclast formation, and neurite outgrowth. Depletion of osteocyte NPY significantly attenuates DMM-induced osteoarthritis and abolishes the benefits of intermittent fasting on osteoarthritis. This study suggests that osteocyte NPY is a key contributing factor in the pathogenesis of osteoarthritis and intermittent fasting represents a promising nonpharmacological antiosteoarthritis method by targeting osteocyte NPY.

Abstract Background and aims Refractory epilepsy is also known as drug-resistant epilepsy with limited clinical treatment. Benefitting from its safety and easy availability, olfactory mucosa mesenchymal stem cells (OM-MSCs) are considered a preferable MSC source for clinical application. This study aims to investigate whether OM-MSCs are a promising alternative source for treating refractory epilepsy clinically and uncover the mechanism by OM-MSCs administration on an epileptic mouse model. Methods OM-MSCs were isolated from turbinal and characterized by flow cytometry. Autologous human OM-MSCs treatment on a patient was carried out using intrathecal administration. Epileptic mouse model was established by 1 mg/kg scopolamine and 300 mg/kg pilocarpine treatment (intraperitoneal). Stereotaxic microinjection was employed to deliver the mouse OM-MSCs. Mouse electroencephalograph recording was used to investigate the seizures. Brain structure was evaluated by magnetic resonance imaging (MRI). Immunohistochemical and immunofluorescent staining of GFAP, IBA1, MAP2, TUBB3, OLIG2, CD4, CD25, and FOXP3 was carried out to investigate the neural cells and Treg cells. QRT-PCR and ELISA were performed to determine the cytokines (Il1b, Il6, Tnf, Il10) on mRNA and protein level. Y-maze, the object location test, and novel object recognition test were performed to measure the cognitive function. Footprint test, rotarod test, balance beam test, and grip strength test were conducted to evaluate the locomotive function. Von Frey testing was carried out to assess the mechanical allodynia. Results Many beneficial effects of the OM-MSC treatment on disease status, including seizure type, frequency, severity, duration, and cognitive function, and no apparent adverse effects were observed at the 8-year follow-up case. Brain MRI indicated that autologous OM-MSC treatment alleviated brain atrophy in epilepsy patients. A study in an epileptic mouse model revealed that OM-MSC treatment recruited Treg cells to the brain, inhibited inflammation, rebuilt the neural network, and improved the cognitive, locomotive, and perceptive functions of epileptic mice. Conclusions Autologous OM-MSC treatment is efficacious for improving chronic refractory epilepsy, suggesting a future therapeutic candidate for epilepsy. Trial registration: The study was registered with Chinese Clinical Trial Registry (ChiCTR2200055357).

Endothelial cells (ECs) and bone marrow stromal cells (BMSCs) play crucial roles in supporting hematopoiesis and hematopoietic regeneration. However, whether ECs are a source of BMSCs remains unclear. Here, we evaluate the contribution of endothelial-to-mesenchymal transition to BMSC generation in postnatal mice. Single-cell RNA sequencing identifies ECs expressing BMSC markers Prrx1 and Lepr ; however, this could not be validated using Prrx1-Cre and Lepr-Cre transgenic mice. Additionally, only a minority of BMSCs are marked by EC lineage tracing models using Cdh5-rtTA-tetO-Cre or Tek-CreERT2 . Moreover, Cdh5 + BMSCs and Tek + BMSCs show distinct spatial distributions and characteristic mesenchymal markers, suggestive of their origination from different progenitors rather than CDH5 + TEK + ECs. Furthermore, myeloablation induced by 5-fluorouracil treatment does not increase Cdh5 + BMSCs. Our findings indicate that ECs hardly convert to BMSCs during homeostasis and myeloablation-induced hematopoietic regeneration, highlighting the importance of using appropriate genetic models and conducting careful data interpretation in studies concerning endothelial-to-mesenchymal transition.

Inadequate osteogenesis and excessive adipogenesis of bone marrow mesenchymal stem cells (BMSCs) are key factors in the pathogenesis of osteoporosis. Patients with Alzheimer's disease (AD) have a higher incidence of osteoporosis than healthy adults, but the underlying mechanism is not clear. Here, we show that brain-derived extracellular vesicles (EVs) from adult AD or wild-type mice can cross the blood-brain barrier to reach the distal bone tissue, while only AD brain-derived EVs (AD-B-EVs) significantly promote the shift of the BMSC differentiation fate from osteogenesis to adipogenesis and induce a bone-fat imbalance. MiR-483-5p is highly enriched in AD-B-EVs, brain tissues from AD mice, and plasma-derived EVs from AD patients. This miRNA mediates the anti-osteogenic, pro-adipogenic, and pro-osteoporotic effects of AD-B-EVs by inhibiting Igf2. This study identifies the role of B-EVs as a promoter of osteoporosis in AD by transferring miR-483-5p.

Alzheimer's disease (AD) is a common degenerative disease among the elderly population. In addition to cognitive impairment, AD is often accompanied by behavioral manifestations. However, little attention has been paid to changes in bone metabolism and related mechanisms in patients with AD. We found that AD mice (APPswe/PS1dE9) had reduced bone density, weakened bone strength, and amyloid beta (Aβ) deposition in the bone tissue. It was further found that targeting autophagy receptors Optineurin (OPTN) and Sequestosome 1 (SQSTM1) increased bone density and bone strength in AD mice, promoted the clearance of Aβ in the bone tissue, and maintained bone homeostasis. Our study suggests that abnormal Aβ deposition may be the co-pathogenesis of AD and osteoporosis (OP). Targeting OPTN and SQSTM1 has a dual-functional effect of alleviating both AD and OP through selective autophagy that specifically targets Aβ for clearance. Therapeutic strategies targeting autophagy may help guide the treatment of patients with AD complicated with OP.

Both Alzheimer's disease (AD) and osteoporosis (OP) are common age-associated degenerative diseases and are strongly correlated with clinical epidemiology. However, there is a lack of clear pathological relationship between the brain and bone in the current understanding. Here, it is found that young osteocyte, the most abundant cells in bone, secretes extracellular vesicles (OCYYoung -EVs) to ameliorate cognitive impairment and the pathogenesis of AD in APP/PS1 mice and model cells. These benefits of OCYYoung -EVs are diminished in aged osteocyte-derived EVs (OCYAged -EVs). Based on the self-constructed OCY-EVs tracer transgenic mouse models and the in vivo fluorescent imaging system, OCY-EVs have been observed to be transported to the brain under physiological and pathological conditions. In the hippocampal administration of Aβ40 induced young AD model mice, the intramedullary injection of Rab27a-shRNA adenovirus inhibits OCYYoung -EVs secretion from bone and aggravates cognitive impairment. Proteomic quantitative analysis reveals that OCYYoung -EVs, compared to OCYAged -EVs, enrich multiple protective factors of AD pathway. The study uncovers the role of OCY-EV as a regulator of brain health, suggesting a novel mechanism in bone-brain communication.

Alzheimer’s disease (AD) is a common neurodegenerative disease that contributes to 60–70

Osteonecrosis of the femoral head (ONFH) commonly occurs after glucocorticoid (GC) therapy. The gut microbiota (GM) participates in regulating host health, and its composition can be altered by GC. Here, this study demonstrates that cohousing with healthy mice or colonization with GM from normal mice attenuates GC-induced ONFH. 16S rRNA gene sequencing shows that cohousing with healthy mice rescues the GC-induced reduction of gut Lactobacillus animalis. Oral supplementation of L. animalis mitigates GC-induced ONFH by increasing angiogenesis, augmenting osteogenesis, and reducing cell apoptosis. Extracellular vesicles from L. animalis (L. animalis-EVs) contain abundant functional proteins and can enter the femoral head to exert proangiogenic, pro-osteogenic, and antiapoptotic effects, while its abundance is reduced after exposure to GC. Our study suggests that the GM is involved in protecting the femoral head by transferring bacterial EVs, and that loss of L. animalis and its EVs is associated with the development of GC-induced ONFH.

The etiology of epilepsy remains undefined in two-thirds of patients. Here, we identified a de novo variant of ATP1A2 (c.2426 T > G, p.Leu809Arg), which encodes the α2 subunit of Na+/K+-ATPase, from a family with idiopathic epilepsy. This variant caused epilepsy with hemiplegic migraine in the study patients. We generated the point variant mouse model Atp1a2L809R, which recapitulated the epilepsy observed in the study patients. In Atp1a2L809R/WT mice, convulsions were observed and cognitive and memory function was impaired. This variant affected the potassium binding function of the protein, disabling its ion transport ability, thereby increasing the frequency of nerve impulses. Valproate (VPA) and Carbamazepine (CBZ) have limited therapeutic efficacy in ameliorating the epileptic syndromes of Atp1a2L809R/WT mice. Our work revealed that ATP1A2L809R variants cause a predisposition to epilepsy. Moreover, we provide a point variant mouse model for epilepsy research and drug screening.

Background : Amyotrophic lateral sclerosis（ALS） is irreversible and fatal within 3–5years, with limited options for treatment. It is imperative to develop a symptombased treatment that may increase the survival of ALS patients and improve their quality of life. Inflammation status, especially elevated interleukin 1β（IL1β）, has been reported to play a critical role in ALS progression. Our study determined that neutralizing circulating IL1β slows down the progression of ALS in an ALS mouse model.Methods : The ALS mouse model was developed by microinjection of lentiviruscarrying OPTN E478G （optineurin, a mutation from ALS patients） into the intra-motor cortex of mice. Peripheral circulating IL1β was neutralized by injecting anti-IL1β antibody into the tail vein. Enzyme-l inked immunosorbent assay（ELISA） and real-time polymerase chain reaction（RT-PCR） were carried out to determine the protein and gene expression levels of IL1β. TUNEL assay was used to assess the neural cell death.Immunofluorescent staining of MAP2 and CASP3 was accomplished to evaluate neuronal cell apoptosis. Glial fibrillary acidic protein staining was performed to analyze the number of astrocytes. Rotarod test, grip strength test, balance beam test,and footprint test were conducted to assess the locomotive function after anti-IL1βtreatment.Results : The model revealed that neuroinflammation contributes to ALS progression.ALS mice exhibited elevated neuroinflammation and IL1β secretion. After anti-IL1βtreatment, ALS mice revealed decreased neural cell death and astrogliosis and gained improved muscle strength and motor ability.Conclusions : Blocking IL1β is a promising strategy to slow down the progression of ALS.