Cerebral ischemia-reperfusion (I/R) injury often leads to neuronal death through persistent neuroinflammatory responses. Recent research has unveiled a unique inflammatory programmed cell death mode known as PANoptosis. However, direct evidence for PANoptosis in ischemic stroke-induced neuronal death has not been established. Although it is widely thought that modulating the balance of microglial phenotypic polarization in cerebral I/R could mitigate neuroinflammation-mediated neuronal death, it remains unknown whether microglial polarization influences PANoptotic neuronal death triggered by cerebral I/R. Our prior study demonstrated that curcumin (CUR) preconditioning could boost the neuroprotective properties of olfactory mucosa-derived mesenchymal stem cells (OM-MSCs) in intracerebral hemorrhage. Yet, the potential neuroprotective capacity of curcumin-pretreated OM-MSCs (CUR-OM-MSCs) on reducing PANoptotic neuronal death during cerebral I/R injury through modulating microglial polarization is uncertain. To mimic cerebral I/R injury, We established in vivo models of reversible middle cerebral artery occlusion (MCAO) in C57BL/6 mice and in vitro models of oxygen-glucose deprivation/reoxygenation (OGD/R) in HT22 neurons and BV2 microglia. Our findings indicated that cerebral I/R injury caused PANoptotic neuronal death and triggered microglia to adopt an M1 (pro-inflammatory) phenotype both in vivo and in vitro. Curcumin pretreatment enhanced the proliferation and anti-inflammatory capacity of OM-MSCs. The CUR-OM-MSCs group experienced a more pronounced reduction in PANoptotic neuronal death and a better recovery of neurological function than the OM-MSCs group. Bioinformatic analysis revealed that microRNA-423-5p (miRNA-423-5p) expression was obviously upregulated in CUR-OM-MSCs compared to OM-MSCs. CUR-OM-MSCs treatment induced the switch to an M2 (anti-inflammatory) phenotype in microglia by releasing miRNA-423-5p, which targeted nucleotide-binding oligomerization domain 2 (NOD2), an upstream regulator of NF-kappaB (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) signaling pathways, to attenuate PANoptotic neuronal death resulting from cerebral I/R. This results provide the first demonstration of the existence of PANoptotic neuronal death in cerebral I/R conditions. Curcumin preconditioning enhanced the ameliorating effect of OM-MSCs on neuroinflammation mediated by microglia polarization via upregulating the abundance of miRNA-423-5p. This intervention effectively alleviates PANoptotic neuronal death resulting from cerebral I/R. The combination of curcumin with OM-MSCs holds promise as a potentially efficacious treatment for cerebral ischemic stroke in the future.

The mechanism of Golgi apparatus (GA) stress responses mediated by GOLPH3 has been widely studied in ischemic stroke, and the neuroprotection effect of olfactory mucosa mesenchymal stem cells (OM‐MSCs) against cerebral ischemia/reperfusion injury (IRI) has been preliminarily presented. However, the exact role of OM‐MSCs in the GA stress response following cerebral IRI remains to be elucidated. In the present study, we used an oxygen‐glucose deprivation/reoxygenation (OGD/R) model and reversible middle cerebral artery occlusion (MCAO) model to simulate cerebral IRI in vitro and in vivo. Our results showed that the level of GOLPH3 protein, reactive oxygen species (ROS), and Ca²⁺ was upregulated, SPCA1 level was downregulated, and GA fragmentation was increased in ischemic stroke models, and OM‐MSC treatment clearly ameliorated these GA stress responses in vitro and in vivo. Subsequently, the knockdown of PEDF in OM‐MSCs using PEDF‐specific siRNA further demonstrated that secretion of PEDF in OM‐MSCs protected OGD/R‐treated N2a cells and MCAO rats from GA stress response. Additionally, rescue experiment using specific pathway inhibitors suggested that OM‐MSCs could promote the phosphorylation of the PI3K/Akt/mTOR pathway, thereby mitigating OGD/R‐induced GA stress response and excessive autophagy. In conclusion, OM‐MSCs minimized the GA stress response following cerebral IRI, at least partially, through the PEDF‐PI3K/Akt/mTOR pathway.

Umbilical cord-derived mesenchymal stem cells (UC-MSCs) engraftment is a potential therapy for cerebral ischemic stroke. However, the harsh microenvironment induced by cerebral ischemia/reperfusion restricts the survival rate and therapeutic efficiency of the engrafted UC-MSCs. In this study, we explored whether small extracellular vesicles (EVs) derived from injured neuronal cells following exposure to cerebral ischemia/reperfusion insult affect the survival of transplanted UC-MSCs. To establish a simulation of cerebral ischemia/reperfusion microenvironment comprising engrafted UC-MSCs and neuronal cells, we cocultured EVs derived from injured N2A cells, caused by exposure to oxygen-glucose deprivation and reperfusion (OGD/R) insult, with UC-MSCs in a conditioned medium. Coculture of UC-MSCs with EVs exacerbated the OGD/R-induced apoptosis and oxidative stress. Suppression of EVs-release via knock-down of Rab27a effectively protected the UC-MSCs from OGD/R-induced insult. Moreover, hypoxia preconditioning not only elevated the survival of UC-MSCs but also improved the paracrine mechanism of injured N2A cells. Altogether, these results show that EVs from injured N2A cells exacerbates OGD/R-induced injury on transplanted UC-MSCs in vitro. Hypoxia preconditioning enhances the survival of the engrafted-UC-MSCs; hence, thus could be an effective approach for improving UC-MSCs therapy in ischemic stroke.

Mechanical loading is required for bone homeostasis, but the underlying mechanism is still unclear. Our previous studies revealed that the mechanical protein polycystin-1 (PC1, encoded by Pkd1) is critical for bone formation. However, the role of PC1 in bone resorption is unknown. Here, we found that PC1 directly regulates osteoclastogenesis and bone resorption. The conditional deletion of Pkd1 in the osteoclast lineage resulted in a reduced number of osteoclasts, decreased bone resorption, and increased bone mass. A cohort study of 32,500 patients further revealed that autosomal dominant polycystic kidney disease, which is mainly caused by loss-of-function mutation of the PKD1 gene, is associated with a lower risk of hip fracture than those with other chronic kidney diseases. Moreover, mice with osteoclast-specific knockout of Pkd1 showed complete resistance to unloading-induced bone loss. A mechanistic study revealed that PC1 facilitated TAZ nuclear translocation via the C-terminal tail-TAZ complex and that conditional deletion of Taz in the osteoclast lineage resulted in reduced osteoclastogenesis and increased bone mass. Pharmacological regulation of the PC1-TAZ axis alleviated unloading- and estrogen deficiency- induced bone loss. Thus, the PC1-TAZ axis may be a potential therapeutic target for osteoclast-related osteoporosis.

Oxidative stress is essential in brain injury after intracerebral hemorrhage (ICH). Ferroptosis, iron-dependent oxidative cell death, overwhelms the antioxidant system. Recently, Olfactory mucosa-derived mesenchymal stem cells (OM-MSCs) hold great potential for treating ferroptosis-mediated oxidative brain damage after ICH. However, massive grafted cell death, possibly caused by a hostile host brain microenvironment, lessens the effectiveness of OM-MSCs. Therefore, it is necessary to develop strategies to upregulate the therapeutic efficacy of OM-MSCs in ICH. Curcumin, a well-established traditional herbal substance, has potent antioxidant property. In the present study, curcumin preconditioning might enhance the anti-oxidative activity of OM-MSCs, thereby augmenting the therapeutic efficacy of OM-MSCs in ICH. In vitro model of ICH, we demonstrated that curcumin-preconditioned OM-MSCs co-culture is more effective in attenuating the cell injury, oxidative stress, and ferroptosis of neuronal cells compared to the native OM-MSCs treatment. In vivo model of ICH, transplantation of curcumin-preconditioned OM-MSCs also showed better neuroprotective effects. Moreover, curcumin pretreatment promoted the survival of OM-MSCs under a conditioned medium from hemin-insulted neurons by improving the anti-oxidative capacities of OM-MSCs. Collectively, our investigation suggested that curcumin preconditioning effectively enhanced the survival and neuroprotective effects of OM-MSCs in the ICH model by upregulating the anti-oxidative capacities of OM-MSCs. Curcumin-preconditioned OM-MSCs might be taken as a novel therapeutic strategy for treating ICH.

Intestinal ischemia-reperfusion (II/R) injury represents a life-threatening and complex pathophysiological process that remains challenging to treat clinically, and emerging evidence suggests that ferroptosis plays an essential role in its pathogenesis. This study aimed to investigate whether extracellular vesicles derived from bone marrow mesenchymal stem cells (BMSC-EVs) can mitigate II/R-induced ferroptosis in a murine model. Using a bioinformatics database, we initially identified genes with abnormal expression patterns in II/R injury. Then, we confirmed the association between II/R injury, ferroptosis, and the HMGB1/SREBF2 axis through in vivo and in vitro experiments. To determine the role of HMGB1 in hypoxia/reoxygenation (H/R)-induced ferroptosis in Caco-2 cells, we transfected cells with either sh-HMGB1 or control sh-NC constructs and developed an H/R model in vitro. Subsequently, we examined factors regulating HMGB1-mediated ferroptosis in Caco-2 cells and assessed the effect of BMSC-EVs on this process. To further explore the mechanism underlying the protective effects of BMSC-EVs in II/R injury, we screened for miRNAs with reduced expression during II/R and verified their involvement. Among these, miR-378a-3p was identified as a candidate for regulating ferroptosis. To confirm its functional role, we treated II/R mice with BMSC-EVs overexpressing miR-378a-3p and assessed the outcomes. Our findings revealed that HMGB1, which is a key regulatory factor of ferroptosis, was significantly upregulated during II/R injury, and its knockdown alleviated H/R-induced ferroptosis in Caco-2 cells. We also found that SREBF2 directly regulates HMGB1 expression to promote H/R-induced ferroptosis in vitro. Importantly, BMSC-EVs alleviated II/R injury by suppressing ferroptosis in Caco-2 cells, and mechanistically, miR-378a-3p, a miRNA derived from BMSC-EVs, inhibited II/R-induced ferroptosis by modulating the SREBF2/HMGB1 axis. In conclusion, BMSC-EVs may exert protective effects against II/R injury by delivering miR-378a-3p, which regulates the SREBF2/HMGB1 axis to suppress ferroptosis, providing important insights into the pathological mechanisms underlying II/R injury and potential therapeutic strategies for its management.