Apoptotic vesicles rejuvenate mesenchymal stem cells via Rab7-mediated autolysosome formation and alleviate bone loss in aging mice

Aging skeletons display decreased bone mass,increased marrow adiposity,and impaired bone marrow mesenchymal stem cells(MSCs).Apoptosis is a programmed cell death process that generates a large number of apoptotic vesicles(apoVs).Dysregulated apoptosis has been closely linked to senescence-associated diseases.However,whether apoVs mediate agingrelated bone loss is not clear.In this study,we showed that young MSC-derived apoVs effectively rejuvenated the nuclear abnormalities of aged bone marrow MSCs and restored their impaired self-renewal,osteo-/adipo-genic lineage differentiation capacities via activating autophagy.Mechanistically,apoptotic young MSCs generated and enriched a high level of Ras-related protein 7(Rab7)into apoVs.Subsequently,recipient aged MSCs reused apoV-derived Rab7 to restore autolysosomes formation,thereby contributing to autophagy flux activation and MSC rejuvenation.Moreover,systemic infusion of young MSC-derived apoVs enhanced bone mass,reduced marrow adiposity,and recused the impairment of recipient MSCs in aged mice.Our findings reveal the role of apoVs in rejuvenating aging-MSCs via restoring autolysosome formation and provide a potential approach for treating age-related bone loss.

A High-Contrast Autolysosome Probe for Detecting Interaction between Autophagosomes and Autolysosomes in Mitophagy

Comprehensive Summary,Autophagy is a multi-step cell metabolism process in which cells remove damaged and unwanted materials.During autophagy,autophagosomes fuse with lysosomes to form autophagosomes.Autophagosomal membrane components are recycled from autolysosomes through the autophagosomal components recycling(ACR),while lysosomal components circulate on the autolysosomal surface through the autophagic lysosome reformation(ALR)process.Autolysosomes contain components from autophagosomes and lysosomes.However,whether there is a fusion between autolysosome and autophagosome or lysosome at the organelle level remains unknown.In this study,a pH and viscosity dual-controlled mitochondria-targeting fluorescent probe Mito-Q was designed based on an asymmetric norcyanine to achieve the high-contrast imaging of mitochondria-containing autolysosomes.Mito-Q not only effectively detected mitochondrial viscosity changes and mitophagy with high sensitivity,but more importantly,the fusion of mitochondria-containing autolysosomes and autophagosomes(FMAA)was observed during autophagy by the real-time confocal imaging of HeLa cells.

High-frequency spinal cord stimulation produces longlasting analgesic effects by restoring lysosomal function and autophagic flux in the spinal dorsal horn

High-frequency spinal cord stimulation(HF-SCS) has been established as an effective therapy for neuropathic pain. However, the analgesic mechanisms involved in HF-SCS remain to be clarified. In our study, adult rat neuropathic pain was induced by spinal nerve ligation. Two days after modeling, the rats were subjected to 4 hours of HF-SCS(motor threshold 50%, frequency 10,000 Hz, and pulse width 0.024 ms) in the dorsal horn of the spinal cord. The results revealed that the tactile allodynia of spinal nerve-injured rats was markedly alleviated by HFSCS, and the effects were sustained for 3 hours after the stimulation had ceased. HF-SCS restored lysosomal function, increased the levels of lysosome-associated membrane protein 2(LAMP2) and the mature form of cathepsin D(matu-CTSD), and alleviated the abnormally elevated levels of microtubule-associated protein 1 A/B-light chain 3(LC3)-II and sequestosome 1(P62) in spinal nerve-injured rats. HF-SCS also mostly restored the immunoreactivity of LAMP2, which was localized in neurons in the superficial layers of the spinal dorsal horn in spinal nerve-injured rats. In addition, intraperitoneal administration of 15 mg/kg chloroquine for 60 minutes reversed the expression of the aforementioned proteins and shortened the timing of the analgesic effects of HF-SCS. These findings suggest that HF-SCS may exhibit longlasting analgesic effects on neuropathic pain in rats through improving lysosomal dysfunction and alleviating autophagic flux. This study was approved by the Laboratory Animal Ethics Committee of China Medical University, Shenyang, China(approval No. 2017 PS196 K) on March 1, 2017.

Engineering cannabidiol synergistic carbon monoxide nanocomplexes to enhance cancer therapy via excessive autophagy

Although carbon monoxide(CO)-based treatments have demonstrated the high cancer efficacy by promoting mitochondrial damage and core-region penetrating ability,the efficiency was often compromised by protective autophagy(mitophagy).Herein,cannabidiol(CBD)is integrated into biomimetic carbon monoxide nanocomplexes(HMPOC@M)to address this issue by inducing excessive autophagy.The biomimetic membrane not only prevents premature drugs leakage,but also prolongs blood circulation for tumor enrichment.After entering the acidic tumor microenvironment,carbon monoxide(CO)donors are stimulated by hydrogen oxide(H_(2)O_(2))to disintegrate into CO and Mn^(2+).The comprehensive effect of CO/Mn^(2+)and CBD can induce ROS-mediated cell apoptosis.In addition,HMPOC@Mmediated excessive autophagy can promote cancer cell death by increasing autophagic flux via classⅢPI3K/BECN1 complex activation and blocking autolysosome degradation via LAMP1 downregulation.Furthermore,in vivo experiments showed that HMPOC@M+laser strongly inhibited tumor growth and attenuated liver and lung metastases by downregulating VEGF and MMP9 proteins.This strategy may highlight the pro-death role of excessive autophagy in TNBC treatment,providing a novel yet versatile avenue to enhance the efficacy of CO treatments.Importantly,this work also indicated the applicability of CBD for triple-negative breast cancer(TNBC)therapy through excessive autophagy.

Chlorpromazine protects against acetaminophen-induced liver injury in mice by modulating autophagy and c-Jun N-terminal kinase activation

Background and aim:Overdose of acetaminophen(APAP)leads to liver injury,which is one of the most common causes of liver failure in the United States.We previously demonstrated that pharmacological activation of autophagy protects against APAP-induced liver injury in mice via removal of damaged mitochondria and APAP-adducts(APAP-ADs).Using an image-based high-throughput screening for autophagy modulators,we recently identified that chlorpromazine(CPZ),a dopamine inhibitor used for anti-schizophrenia,is a potent autophagy inducer in vitro.Therefore,the aim of the present study is to determine whether CPZ may protect against APAP-induced liver injury via inducing autophagy.Methods:Wild type C57BL/6J mice were injected with APAP to induce liver injury.CPZ was administrated either at the same time with APAP(co-treatment)or 2 h later after APAP administration(post-treat-ment).Hemotoxyline and eosin(H&E)staining of liver histology,terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling(TUNEL)staining of necrotic cell death as well as serum levels of alanine aminotransferase(ALT)were used to monitor liver injury.Results:We found that CPZ markedly protected against APAP-induced liver injury as demonstrated by decreased serum levels of ALT,liver necrotic areas as well as TUNEL-positive cells in mice that were either co-treated or post-treated with CPZ.Mechanistically,we observed that CPZ increased the number of autolysosomes and decreased APAP-induced c-Jun N-terminal kinase activation without affecting the metabolic activation of APAP.Pharmacological inhibition of autophagy by chloroquine partially weak-ened the protective effects of CPZ against APAP-induced liver injury.Conclusions:Our results indicate that CPZ ameliorates APAP-induced liver injury partially via activating hepatic autophagy and inhibiting JNK activation.