Mitochondrial transfer from bone-marrow-derived mesenchymal stromal cells to chondrocytes protects against cartilage degenerative mitochondrial dysfunction in rats chondrocytes

Background:Previous studies have reported that mitochondrial dysfunction participates in the pathological process of osteoarthritis(OA).However,studies that improve mitochondrial function are rare in OA.Mitochondrial transfer from mesenchymal stem cells(MSCs)to OA chondrocytes might be a cell-based therapy for the improvement of mitochondrial function to prevent cartilage degeneration.This study aimed to determine whether MSCs can donate mitochondria and protect the mitochondrial function and therefore reduce cartilage degeneration.Methods:Bone-marrow-derived mesenchymal stromal cells(BM-MSCs)were harvested from the marrow cavities of femurs and tibia in young rats.OA chondrocytes were gathered from the femoral and tibial plateau in old OA model rats.BM-MSCs and OA chondrocytes were co-cultured and mitochondrial transfer from BM-MSCs to chondrocytes was identified.Chondrocytes with mitochondria transferred from BM-MSCs were selected by fluorescence-activated cell sorting.Mitochondrial function of these cells,including mitochondrial membrane potential(Δψm),the activity of mitochondrial respiratory chain(MRC)enzymes,and adenosine triphosphate(ATP)content were quantified and compared to OA chondrocytes without mitochondrial transfer.Chondrocytes proliferation,apoptosis,and secretion ability were also analyzed between the two groups.Results:Mitochondrial transfer was found from BM-MSCs to OA chondrocytes.Chondrocytes with mitochondrial from MSCs(MSCs+OA group)showed increased mitochondrial membrane potential compared with OA chondrocytes without mitochondria transfer(OA group)(1.79±0.19 vs.0.71±0.12,t=10.42,P<0.0001).The activity of MRC enzymes,including MRC complex I,II,III,and citrate synthase was also improved(P<0.05).The content of ATP in MSCs+OA group was significantly higher than that in OA group(161.90±13.49 vs.87.62±11.07 nmol/mg,t=8.515,P<0.0001).Meanwhile,we observed decreased cell apoptosis(7.09%±0.68%vs.15.89%±1.30%,t=13.39,P<0.0001)and increased relative secretion of type II collagen(2.01±0.14 vs.1.06±0.11,t=9.141,P=0.0008)and proteoglycan protein(2.08±0.20 vs.0.97±0.12,t=8.227,P=0.0012)in MSCs+OA group,contrasted with OA group.Conclusions:Mitochondrial transfer from BM-MSCs provided protection for OA chondrocytes against mitochondrial dysfunction and degeneration through improving mitochondrial function,cell proliferation,and inhibiting apoptosis in chondrocytes.This finding may offer a new therapeutic direction for OA.

Oxidative stress and mitochondrial transfer:A new dimension towards ocular diseases

Ocular cells like,retinal pigment epithelium(RPE)is a highly specialized pigmented monolayer of post-mitotic cells,which is located in the posterior segment of the eye between neuro sensory retina and vascular choroid.It functions as a selective barrier and nourishes retinal visual cells.As a result of high-level oxygen consumption of retinal cells,RPE cells are vulnerable to chronic oxidative stress and an increased level of reactive oxygen species(ROS)generated from mitochondria.These oxidative stress and ROS generation in retinal cells lead to RPE degeneration.Various sources including mtDNA damage could be an important factor of oxidative stress in RPE.Gene therapy and mitochondrial transfer studies are emerging fields in ocular disease research.For retinal degenerative diseases stem cell-based transplantation methods are developed from basic research to preclinical and clinical trials.Translational research contributions of gene and cell therapy would be a new strategy to prevent,treat and cure various ocular diseases.This review focuses on the effect of oxidative stress in ocular cell degeneration and recent translational researches on retinal degenerative diseases to cure blindness.

Human iPSCs derived astrocytes rescue rotenone-induced mitochondrial dysfunction and dopaminergic neurodegeneration in vitro by donating functional mitochondria

Background Parkinson’s disease(PD)is one of the neurodegeneration diseases characterized by the gradual loss of dopaminergic(DA)neurons in the substantia nigra region of the brain.Substantial evidence indicates that at the cellular level mitochondrial dysfunction is a key factor leading to pathological features such as neuronal death and accumulation of misfoldedα-synuclein aggregations.Autologous transplantation of healthy purified mitochondria has shown to attenuate phenotypes in vitro and in vivo models of PD.However,there are significant technical difficulties in obtaining large amounts of purified mitochondria with normal function.In addition,the half-life of mitochondria varies between days to a few weeks.Thus,identifying a continuous source of healthy mitochondria via intercellular mitochondrial transfer is an attractive option for therapeutic purposes.In this study,we asked whether iPSCs derived astrocytes can serve as a donor to provide functional mitochondria and rescue injured DA neurons after rotenone exposure in an in vitro model of PD.Methods We generated DA neurons and astrocytes from human iPSCs and hESCs.We established an astroglial-neuronal co-culture system to investigate the intercellular mitochondrial transfer,as well as the neuroprotective effect of mitochondrial transfer.We employed immunocytochemistry and FACS analysis to track mitochondria.Results We showed evidence that iPSCs-derived astrocytes or astrocytic conditioned media(ACM)can rescue DA neurons degeneration via intercellular mitochondrial transfer in a rotenone induced in vitro PD model.Specifically,we showed that iPSCs-derived astrocytes from health spontaneously release functional mitochondria into the media.Mito-Tracker Green tagged astrocytic mitochondria were detected in the ACM and were shown to be internalized by the injured neurons via a phospho-p38 depended pathway.Transferred mitochondria were able to significantly reverse DA neurodegeneration and axonal pruning following exposure to rotenone.When rotenone injured neurons were cultured in presence of ACM depleted of mitochondria(by ultrafiltration),the neuroprotective effects were abolished.Conclusions Our studies provide the proof of principle that iPSCs-derived astrocytes can act as mitochondria donor to the injured DA neurons and attenuate pathology.Using iPSCs derived astrocytes as a donor can provide a novel strategy that can be further developed for cellular therapy for PD.

Alda-1 treatment promotes the therapeutic effect of mitochondrial transplantation for myocardial ischemia-reperfusion injury

Mitochondrial damage is a critical driver in myocardial ischemia-reperfusion(I/R)injury and can be alleviated via the mitochondrial transplantation.The efficiency of mitochondrial transplantation is determined by mitochondrial vitality.Because aldehyde dehydrogenase 2(ALDH2)has a key role in regulating mitochondrial homeostasis,we aimed to investigate its potential therapeutic effects on mitochondrial transplantation via the use of ALDH2 activator,Alda-1.Our present study demonstrated that time-dependent internalization of exogenous mitochondria by cardiomyocytes along with ATP production were significantly increased in response to mitochondrial transplantation.Furthermore,Alda-1 treatment remarkably promoted the oxygen consumption rate and baseline mechanical function of cardiomyocytes caused by mitochondrial transplantation.Mitochondrial transplantation inhibited cardiomyocyte apoptosis induced by the hypoxia-reoxygenation exposure,independent of Alda-1 treatment.However,promotion of the mechanical function of cardiomyocytes exposed to hypoxia-reoxygenation treatment was only observed after mitochondrial Alda-1 treatment and transplantation.By using a myocardial I/R mouse model,our results revealed that transplantation of Alda-1-treated mitochondria into mouse myocardial tissues limited the infarction size after I/R injury,which was at least in part due to increased mitochondrial potential-mediated fusion.In conclusion,ALDH2 activation in mitochondrial transplantation shows great potential for the treatment of myocardial I/R injury.