Young Sca-1+ bone marrow stem cell-derived exosomes preserve visual function via the miR-150-5p/MEKK3/JNK/c-Jun pathway to reduce M1 microglial polarization.

BACKGROUND: Polarization of microglia, the resident retinal immune cells, plays important roles in mediating both injury and repair responses post-retinal ischemia-reperfusion (I/R) injury, which is one of the main pathological mechanisms behind ganglion cell apoptosis. Aging could perturb microglial balances, resulting in lowered post-I/R retinal repair. Young bone marrow (BM) stem cell antigen 1-positive (Sca-1+) cells have been demonstrated to have higher reparative capabilities post-I/R retinal injury when transplanted into old mice, where they were able to home and differentiate into retinal microglia. METHODS: Exosomes were enriched from young Sca-1+ or Sca-1- cells, and injected into the vitreous humor of old mice post-retinal I/R. Bioinformatics analyses, including miRNA sequencing, was used to analyze exosome contents, which was confirmed by RT-qPCR. Western blot was then performed to examine expression levels of inflammatory factors and underlying signaling pathway proteins, while immunofluorescence staining was used to examine the extent of pro-inflammatory M1 microglial polarization. Fluoro-Gold labelling was then utilized to identify viable ganglion cells, while H&E staining was used to examine retinal morphology post-I/R and exosome treatment. RESULTS: Sca-1+ exosome-injected mice yielded better visual functional preservation and lowered inflammatory factors, compared to Sca-1-, at days 1, 3, and 7 days post-I/R. miRNA sequencing found that Sca-1+ exosomes had higher miR-150-5p levels, compared to Sca-1- exosomes, which was confirmed by RT-qPCR. Mechanistic analysis found that miR-150-5p from Sca-1+ exosomes repressed the mitogen-activated protein kinase kinase kinase 3 (MEKK3)/JNK/c-Jun axis, leading to IL-6 and TNF-α downregulation, and subsequently reduced microglial polarization, all of which contributes to reduced ganglion cell apoptosis and preservation of proper retinal morphology. CONCLUSION: This study elucidates a potential new therapeutic approach for neuroprotection against I/R injury, via delivering miR-150-5p-enriched Sca-1+ exosomes, which targets the miR-150-5p/MEKK3/JNK/c-Jun axis, thereby serving as a cell-free remedy for treating retinal I/R injury and preserving visual functioning.

Influence of optical zone on myopic correction in small incision lenticule extraction: a short-term study.

BACKGROUND: To evaluate the influence of preoperative optical zone on myopic correction in small incision lenticule extraction. METHODS: In this retrospective clinical study, 581 eyes from 316 patients underwent SMILE were selected, including 117 eyes in the small optical zone group (range from 6.0 to 6.4 mm) and 464 eyes in the large optical zone group (range from 6.5 to 6.8 mm). The measurements included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical, and cylinder were measured preoperatively and 3 months postoperatively. Propensity score match (PSM) analysis was performed with age, gender, eye (right/left), keratometry and preoperative spherical equivalent between two different groups. The influence of optical zones on postoperative refractive outcomes were evaluated using univariate regression analysis. RESULTS: In total, 78 pairs of eyes were selected by PSM (match ratio 1:1). There were no differences in the age, gender, eye (right/left), keratometry or preoperative spherical equivalent between the small and large optical zone groups. However, the difference of postoperative spherical equivalent was significantly between groups. Patients with larger optical zones had a trend towards less undercorrection (P = 0.018). Univariate linear regression model analysis found that each millimeter larger optical zone resulted in 8.13% or 0.39D less undercorrection (P < 0.001). The dependency between the optical zones and postoperative spherical equivalent was significant in the higher preoperative myopia group (r = 0.281, P < 0.001), but not significant in the lower myopia group (r = 0.028, P = 0.702). CONCLUSION: The diameter of optical zones would affect postoperative refractive outcomes in small incision lenticule extraction. This study indicated that larger optical zones induced less undercorrection, especially in patients with high myopia.

Age-related visual impairments and retinal ganglion cells axonal degeneration in a mouse model harboring OPTN (E50K) mutation.

Retinal ganglion cells (RGCs) axons are the signal carriers of visual information between retina and brain. Therefore, they play one of the important roles affected in many optic neurodegenerative diseases like glaucoma. Among the genetic risks associated with glaucoma, the E50K mutation in the Optineurin (OPTN) gene are known to result in glaucoma in the absence of increased intraocular pressure (IOP), whereas the relevant pathological mechanism and neurological issues remain to be further investigated. In this study, the OPTN (E50K) mutant mouse model was established through CRISPR/Cas9-mediated genome editing, and aging-related RGCs loss and the visual dysfunction were identified. In E50K mice 16 months old, the axonal transport decreased comparing to wild-type (WT) mice at the same age. Furthermore, results of electron microscopy demonstrated significant morphological anomaly of mitochondria in RGCs axons of young E50K mice 3 months old, and these changes were aggravated with age. These indicated that the damaged mitochondria-associated dysfunction of RGCs axon should play an etiological role in glaucoma as an age-related outcome of OPTN (E50K) mutation. The findings of this study have potential implications for the targeted prevention and treatment of NTG.

Neuroprotective effects of bone marrow Sca-1+ cells against age-related retinal degeneration in OPTN E50K mice.

Glaucoma is characterized by retinal ganglion cell (RGC) death, the underlying mechanisms of which are still largely unknown. An E50K mutation in the Optineurin (OPTN) gene is a leading cause of normal-tension glaucoma (NTG), which directly affects RGCs in the absence of high intraocular pressure and causes severe glaucomatous symptoms in patients. Bone marrow (BM) stem cells have been demonstrated to play a key role in regenerating damaged tissue during ageing and disease through their trophic effects and homing capability. Here, we separated BM stem cells into Sca-1+ and Sca-1- cells and transplanted them into lethally irradiated aged OPTN E50K mice to generate Sca-1+ and Sca-1- chimaeras, respectively. After 3 months of BM repopulation, we investigated whether Sca-1+ cells maximized the regenerative effects in the retinas of NTG model mice with the OPTN E50K mutation. We found that the OPTN E50K mutation aggravated age-related deficiency of neurotrophic factors in both retinas and BM during NTG development, leading to retinal degeneration and BM dysfunction. Sca-1+ cells from young healthy mice had greater paracrine trophic effects than Sca-1- cells and Sca-1+ cells from young OPTN E50K mice. In addition, Sca-1+ chimaeras demonstrated better visual functions than Sca-1- chimaeras and untreated OPTN E50K mice. More Sca-1+ cells than Sca-1- cells were recruited to repair damaged retinas and reverse visual impairment in NTG resulting from high expression levels of neurotrophic factors. These findings indicated that the Sca-1+ cells from young, healthy mice may have exhibited an enhanced ability to repair retinal degeneration in NTG because of their excellent neurotrophic capability.

Proteomic analysis of aged and OPTN E50K retina in the development of normal tension glaucoma.

Progressive degeneration of retinal ganglion cells (RGCs) is a major characteristic of glaucoma, whose underlying mechanisms are still largely unknown. An E50K mutation in the Optineurin (OPTN) gene is a leading cause of normal tension glaucoma (NTG), directly affecting RGCs without high intraocular pressure and causing severe glaucomatous symptoms in clinical settings. A systematic analysis of the NTG mouse model is crucial for better understanding of the underlying pathological mechanisms for glaucoma. To elucidate proteomic and biochemical pathway alterations during NTG development, we established an OPTN E50K mutant mouse model through CRISPR/Cas9. Retinal proteins from resulting mice exhibiting glaucomatous phenotypes were subject to tandem mass tag-labeled quantitative proteomics and then analyzed through bioinformatics methods to characterize the molecular and functional signatures of NTG. We identified 6364 quantitative proteins in our proteomic analysis. Bioinformatics analysis revealed that OPTN E50K mice experienced protein synthesis dysregulation, age-dependent energy defects and autophagy-lysosome pathway dysfunction. Certain biological features, including amyloid deposition, RNA splicing, microglia activation and reduction of crystallin production, were similar to Alzheimer's disease. Our study is the first to describe proteomic and biochemical pathway alterations in NTG pathogenesis during disease advancement. Several proteomic signatures overlapped with retinal changes found in the ad mice model, suggesting the presence of common mechanisms between age-related degenerative disorders, as well as prospective new targets for diagnostic and therapeutic strategies.

The E50K optineurin mutation impacts autophagy-mediated degradation of TDP-43 and leads to RGC apoptosis in vivo and in vitro.

The glaucoma-associated E50K mutation in optineurin (OPTN) is known to affect autophagy and cause the apoptosis of retinal ganglion cells (RGCs), but the pathogenic mechanism remains unclear. In this study, we investigated whether the OPTN (E50K) mutation caused TDP-43 aggregation by disrupting autophagy in vivo and in vitro. OPTN (E50K) mutant mice were generated and analysed for genotype and phenotype. Adeno-associated virus type 2 vectors containing either GFP only, GFP-tagged wild-type OPTN or GFP-tagged E50K-mutated OPTN were used to transfect R28 cells. Loss of RGCs decreased retinal thickness and visual impairment were observed in OPTN (E50K) mice compared with WT mice. Moreover, overexpression of E50K OPTN induced R28 cell apoptosis. Increased p62/SQSTM1 and LC3-II levels indicated that autophagic flux was inhibited and contributed to TDP-43 aggregation in vivo and in vitro. We found that rapamycin effectively reduced the aggregation of TDP-43 in OPTN (E50K) mice and decreased the protein levels of p62/SQSTM1 and the autophagic marker LC3-II. Moreover, rapamycin increased the RGC number and visual function of E50K mice. In addition, we also observed increased cytoplasmic TDP-43 in the spinal cord and motor dysfunction in 24-month-old OPTN (E50K) mice, indicating that TDP-43 accumulation may be the common pathological mechanism of glaucoma and amyotrophic lateral sclerosis (ALS). In conclusion, the disruption of autophagy by OPTN (E50K) affected the degradation of TDP-43 and may play an important role in OPTN (E50K)-mediated glaucomatous retinal neurodegeneration.

Knock-out of MicroRNA 145 impairs cardiac fibroblast function and wound healing post-myocardial infarction.

Prevention of infarct scar thinning and dilatation and stimulation of scar contracture can prevent progressive heart failure. Since microRNA 145 (miR-145) plays an important role in cardiac fibroblast response to wound healing and cardiac repair after an myocardial infarction (MI), using a miR-145 knock-out (KO) mouse model, we evaluated contribution of down-regulation of miR-145 to cardiac fibroblast and myofibroblast function during adverse cardiac remodelling. Cardiac function decreased more and the infarct size was larger in miR-145 KO than that in WT mice after MI and this phenomenon was accompanied by a decrease in cardiac fibroblast-to-myofibroblast differentiation. Quantification of collagen I and α-SMA protein levels as well as wound contraction revealed that transdifferentiation of cardiac fibroblasts into myofibroblasts was lower in KO than WT mice. In vitro restoration of miR-145 induced more differentiation of fibroblasts to myofibroblasts and this effect involved the target genes Klf4 and myocardin. MiR-145 contributes to infarct scar contraction in the heart and the absence of miR-145 contributes to dysfunction of cardiac fibroblast, resulting in greater infarct thinning and dilatation. Augmentation of miR-145 could be an attractive target to prevent adverse cardiac remodelling after MI by enhancing the phenotypic switch of cardiac fibroblasts to myofibroblasts.

Long-term repopulation of aged bone marrow stem cells using young Sca-1 cells promotes aged heart rejuvenation.

Reduced quantity and quality of stem cells in aged individuals hinders cardiac repair and regeneration after injury. We used young bone marrow (BM) stem cell antigen 1 (Sca-1) cells to reconstitute aged BM and rejuvenate the aged heart, and examined the underlying molecular mechanisms. BM Sca-1+ or Sca-1- cells from young (2-3 months) or aged (18-19 months) GFP transgenic mice were transplanted into lethally irradiated aged mice to generate 4 groups of chimeras: young Sca-1+ , young Sca-1- , old Sca-1+ , and old Sca-1- . Four months later, expression of rejuvenation-related genes (Bmi1, Cbx8, PNUTS, Sirt1, Sirt2, Sirt6) and proteins (CDK2, CDK4) was increased along with telomerase activity and telomerase-related protein (DNA-PKcs, TRF-2) expression, whereas expression of senescence-related genes (p16INK4a , P19ARF , p27Kip1 ) and proteins (p16INK4a , p27Kip1 ) was decreased in Sca-1+ chimeric hearts, especially in the young group. Host cardiac endothelial cells (GFP- CD31+ ) but not cardiomyocytes were the primary cell type rejuvenated by young Sca-1+ cells as shown by improved proliferation, migration, and tubular formation abilities. C-X-C chemokine CXCL12 was the factor most highly expressed in homed donor BM (GFP+ ) cells isolated from young Sca-1+ chimeric hearts. Protein expression of Cxcr4, phospho-Akt, and phospho-FoxO3a in endothelial cells derived from the aged chimeric heart was increased, especially in the young Sca-1+ group. Reconstitution of aged BM with young Sca-1+ cells resulted in effective homing of functional stem cells in the aged heart. These young, regenerative stem cells promoted aged heart rejuvenation through activation of the Cxcl12/Cxcr4 pathway of cardiac endothelial cells.

Glaucoma Drainage Device Coated with Mitomycin C Loaded Opal Shale Microparticles to Inhibit Bleb Fibrosis.

Excessive fibrosis is the topmost factor for the defeat of surgical glaucoma drainage device (GDD) implantation. Adjuvant drug approaches are promising to help reduce the scar formation and excessive fibrosis. Opal shale (OS), as a natural state and noncrystalline silica substance with poriferous nature and strong adsorbability, is highly likely to undertake drug loading and delivery. Here, we employed OS microparticles (MPs) by ultrasound and centrifugation and presented an innovative and improved GDD coated with OS MPs, which were loaded with mitomycin C (MMC). MMC-loaded OS MPs were physically absorbed on the Ahmed glaucoma valve surface through OS' adsorbability. About 5.51 µg of MMC was loaded on the modified Ahmed glaucoma valve and can be released for 18 days in vitro. MMC-loaded OS MPs inhibited fibroblast proliferation and showed low toxicity to primary Tenon's fibroblasts. The ameliorated drainage device was well tolerated and effective in reducing the fibrous reaction in vivo. Hence, our study constructed an improved Ahmed glaucoma valve using OS MPs without disturbing aqueous humor drainage pattern over the valve surface. The modified Ahmed glaucoma valve successfully alleviated scar tissue formation after GDD implantation surgery.

Young bone marrow Sca-1 cells protect aged retina from ischaemia-reperfusion injury through activation of FGF2.

Retinal ganglion cell apoptosis and optic nerve degeneration are prevalent in aged patients, which may be related to the decrease in bone marrow (BM) stem cell number/function because of the possible cross-talk between the two organs. This pathological process is accelerated by retinal ischaemia-reperfusion (I/R) injury. This study investigated whether young BM stem cells can regenerate and repair the aged retina after acute I/R injury. Young BM stem cell antigen 1 positive (Sca-1+ ) or Sca-1- cells were transplanted into lethally irradiated aged recipient mice to generate Sca-1+ and Sca-1- chimaeras, respectively. The animals were housed for 3 months to allow the young Sca-1 cells to repopulate in the BM of aged mice. Retinal I/R was then induced by elevation of intraocular pressure. Better preservation of visual function was found in Sca-1+ than Sca-1- chimaeras 7 days after injury. More Sca-1+ cells homed to the retina than Sca-1- cells and more cells differentiated into glial and microglial cells in the Sca-1+ chimaeras. After injury, Sca-1+ cells in the retina reduced host cellular apoptosis, which was associated with higher expression of fibroblast growth factor 2 (FGF2) in the Sca-1+ chimaeras. Young Sca-1+ cells repopulated the stem cells in the aged retina and diminished cellular apoptosis after acute I/R injury through FGF2 and Akt signalling pathways.

Synergistic neuroprotective effect of rasagiline and idebenone against retinal ischemia-reperfusion injury via the Lin28-let-7-Dicer pathway.

Retinal ischemia-reperfusion (RIR) injury causes neuronal degeneration and initiates various optic nerve diseases. This study aimed to investigate the synergistic neuroprotective effect of rasagiline and idebenone against RIR injury. A combination of rasagiline and idebenone was administered intraperitoneally immediately after establishment of the RIR model. Treatment with the combination of the two drugs resulted in a significant restoration of retinal thickness and retinal ganglion cells. Apoptosis of cells in ganglion cell layers was also ameliorated, suggesting that the effect of the two drugs was synergistic and the expression of brain-derived neurotrophic factor increased. Furthermore, idebenone and rasagiline induced the expression of Lin28A and Lin28B, respectively, which resulted in a reduced expression of microRNAs in the let-7 family and an increased protein output of Dicer. The data obtained from gene overexpression and knockdown experiments indicated that let-7 and Dicer were necessary for the synergistic neuroprotective effect of the two drugs. Our findings suggested that combination therapy with rasagiline and idebenone produced a synergistic effect that ameliorated RIR injury and restored visual function. In addition, the combined treatment provided neuroprotection via enhancement of the selective regulation of let-7 by Lin28A/B. These findings implied that a treatment with the combination of rasagiline and idebenone is a feasible treatment option for optic nerve diseases.

Young Bone-Marrow Sca-1+ Stem Cells Rejuvenate the Aged Heart and Improve Function after Injury through PDGFRß-Akt pathway.

Bone marrow (BM) reconstitution with young BM cells in aged recipients restores the functionality of cardiac resident BM-derived progenitors. This study investigated the cell type primarily responsible for this effect. We reconstituted old mice with BM cells from young or old mice and found that the number of stem cell antigen 1 (Sca-1) cells homing to the heart was significantly greater in young than old chimeras. We then reconstituted old mice with young BM Sca-1+ or Sca-1- cells. We found that Sca-1 cells repopulated the recipient BM and homed to the heart. The number of BM-derived cells in the aged myocardium co-expressing PDGFRß was 3 times greater in Sca-1+ than Sca-1- chimeric mice. Sca-1+ chimeras had more active cell proliferation in the infarcted heart and improved ventricular function after MI. The improved regeneration involved activation of the PDGFRß/Akt/p27Kip1 pathway. Sca-1+ stem cells rejuvenated cardiac tissue in aged mice. Restoration of the Sca-1+ subset of stem cells by BM reconstitution improved cardiac tissue regeneration after injury in aged mice.

Aged Human Multipotent Mesenchymal Stromal Cells Can Be Rejuvenated by Neuron-Derived Neurotrophic Factor and Improve Heart Function After Injury.

Reduced regenerative capacity of aged stem cells hampers the benefits of autologous cell therapy for cardiac regeneration. This study investigated whether neuron-derived neurotrophic factor (NDNF) could rejuvenate aged human bone marrow (hBM)- multipotent mesenchymal stromal cells (MSCs) and whether the rejuvenated hBM-MSCs could improve cardiac repair after ischemic injury. Over-expression of NDNF in old hBM-MSCs decreased cell senescence and apoptosis. Engraftment of NDNF over-expressing old hBM-MSCs into the ischemic area of mouse hearts resulted in improved cardiac function after myocardial infarction, while promoting implanted stem cell survival. Our findings suggest NDNF could be a new factor to rejuvenate aged stem cells and improve their capability to repair the aged heart after injury.

Targeted myocardial delivery of GDF11 gene rejuvenates the aged mouse heart and enhances myocardial regeneration after ischemia-reperfusion injury.

Ischemic cardiac injury is the main contributor to heart failure, and the regenerative capacity of intrinsic stem cells plays an important role in tissue repair after injury. However, stem cells in aged individuals have reduced regenerative potential and aged tissues lack the capacity to renew. Growth differentiation factor 11 (GDF11), from the activin-transforming growth factor ß superfamily, has been shown to promote stem cell activity and rejuvenation. We carried out non-invasive targeted delivery of the GDF11 gene to the heart using ultrasound-targeted microbubble destruction (UTMD) and cationic microbubble (CMB) to investigate the ability of GDF11 to rejuvenate the aged heart and improve tissue regeneration after injury. Young (3 months) and old (21 months) mice were used to evaluate the expression of GDF11 mRNA in the myocardium at baseline and after ischemia/reperfusion (I/R) and myocardial infarction. GDF11 expression decreased with age and following myocardial injury. UTMD-mediated delivery of the GDF11 plasmid to the aged heart after I/R injury effectively and selectively increased GDF11 expression in the heart, and improved cardiac function and reduced infarct size. Over-expression of GDF11 decreased senescence markers, p16 and p53, as well as the number of p16+ cells in old mouse hearts. Furthermore, increased proliferation of cardiac stem cell antigen 1 (Sca-1+) cells and increased homing of endothelial progenitor cells and angiogenesis in old ischemic hearts occurred after GDF11 over-expression. Repetitive targeted delivery of the GDF11 gene via UTMD can rejuvenate the aged mouse heart and protect it from I/R injury.

Decreased expression of miR­9 due to E50K OPTN mutation causes disruption of the expression of BDNF leading to RGC­5 cell apoptosis.

The aims of the present study were to investigate the effect of E50K optineurin (OPTN) mutation on RGC­5 cells and to define the role of microRNA­9 (miR­9) in this system. Transfected RGC­5 cells were used to evaluate the effects of E50K OPTN on the expression of miR­9 and subsequent disruption of RGC­5 cell apoptosis was analyzed using western blotting. The results showed that the expression of E50K OPTN was associated with a marked reduction in the levels of miR­9 in the E50K OPTN­transfected RGC­5 cells. The E50K OPTN­dependent reductions in miR­9 led to increased expression of the transcriptional repressor, RE1­silencing transcription factor and decreased the expression of brain­derived neurotrophic factor. Thus, E50K OPTN may disrupt the expression of miR­9, suggesting a potential mechanism by which E50K OPTN mutation may lead to RGC­5 cell apoptosis.

Non-invasive Macrophage Tracking Using Novel Porphysome Nanoparticles in the Post-myocardial Infarction Murine Heart.

PURPOSE: We generated a folate-conjugated porphyrin nanoparticle (porphysome) suitable for multimodal non-invasive active macrophage tracking post-myocardial infarction (MI). PROCEDURES: Macrophage uptake of folate-conjugated porphysomes was selective. Folate-porphysome cardiac macrophage tracking was detected in vivo using radioligand and fluorescent imaging. To track post-MI macrophage mobilization, cardiac fluorescence signal in folate-porphysome-injected mice was measured for 9 day post-MI. Active macrophage phenotype was assessed using immunohistochemistry. RESULTS: Heart active macrophage presence peaked on day 1, returned to baseline by day 3, and peaked again on day 7 post-MI. Macrophages were distributed throughout the left ventricle at day 1, but aggregated within scar tissue at day 7. Macrophage phenotype was pro-inflammatory (TNFα(+)) at day 1, whereas scar-resident macrophages expressed anti-inflammatory markers (IL-10, TGFß) at day 7. However, day 7 macrophages outside the scar expressed neither pro- nor anti-inflammatory markers. CONCLUSIONS: We established that folate-porphysomes are suitable for non-invasive imaging of macrophages and used it to investigate active macrophage behavior in the infarcted heart.

The cardiac repair benefits of inflammation do not persist: evidence from mast cell implantation.

Multiple mechanisms contribute to progressive cardiac dysfunction after myocardial infarction (MI) and inflammation is an important mediator. Mast cells (MCs) trigger inflammation after MI by releasing bio-active factors that contribute to healing. c-Kit-deficient (Kit(W/W-v) ) mice have dysfunctional MCs and develop severe ventricular dilatation post-MI. We explored the role of MCs in post-MI repair. Mouse wild-type (WT) and Kit(W/W-v) MCs were obtained from bone marrow (BM). MC effects on fibroblasts were examined in vitro by proliferation and gel contraction assays. MCs were implanted into infarcted mouse hearts and their effects were evaluated using molecular, cellular and cardiac functional analyses. In contrast to WT, Kit(W/W-v) MC transplantation into Kit(W/W-v) mice did not improve cardiac function or scar size post-MI. Kit(W/W-v) MCs induced significantly reduced fibroblast proliferation and contraction compared to WT MCs. MC influence on fibroblast proliferation was Basic fibroblast growth factor (bFGF)-dependent and MC-induced fibroblast contractility functioned through transforming growth factor (TGF)-ß. WT MCs transiently rescue cardiac function early post-MI, but the benefits of BM cell implantation lasted longer. MCs induced increased inflammation compared to the BM-injected mice, with increased neutrophil infiltration and infarct tumour necrosis factor-α (TNF-α) concentration. This augmented inflammation was followed by increased angiogenesis and myofibroblast formation and reduced scar size at early time-points. Similar to the functional data, these beneficial effects were transient, largely vanishing by day 28. Dysfunctional Kit(W/W-v) MCs were unable to rescue cardiac function post-MI. WT MC implantation transiently enhanced angiogenesis and cardiac function. These data suggest that increased inflammation is beneficial to cardiac repair, but these effects are not persistent.

Uterine-derived progenitor cells are immunoprivileged and effectively improve cardiac regeneration when used for cell therapy.

Cell therapy to prevent cardiac dysfunction after myocardial infarction (MI) is less effective in aged patients because aged cells have decreased regenerative capacity. Allogeneic transplanted stem cells (SCs) from young donors are usually rejected. Maintaining transplanted SC immunoprivilege may dramatically improve regenerative outcomes. The uterus has distinct immune characteristics, and we showed that reparative uterine SCs home to the myocardium post-MI. Here, we identify immunoprivileged uterine SCs and assess their effects on cardiac regeneration after allogeneic transplantation. We found more than 20% of cells in the mouse uterus have undetectable MHC I expression by flow cytometry. Uterine MHC I((neg)) and MHC I((pos)) cells were separated by magnetic cell sorting. The MHC I((neg)) population expressed the SC markers CD34, Sca-1 and CD90, but did not express MHC II or c-kit. In vitro, MHC I((neg)) and ((pos)) SCs show colony formation and endothelial differentiation capacity. In mixed leukocyte co-culture, MHC I((neg)) cells showed reduced cell death and leukocyte proliferation compared to MHC I((pos)) cells. MHC I((neg)) and ((pos)) cells had significantly greater angiogenic capacity than mesenchymal stem cells. The benefits of intramyocardial injection of allogeneic MHC I((neg)) cells after MI were comparable to syngeneic bone marrow cell transplantation, with engraftment in cardiac tissue and limited recruitment of CD4 and CD8 cells up to 21 days post-MI. MHC I((neg)) cells preserved cardiac function, decreased infarct size and improved regeneration post-MI. This new source of immunoprivileged cells can induce neovascularization and could be used as allogeneic cell therapy for regenerative medicine.

A secreted protein (Canopy 2, CNPY2) enhances angiogenesis and promotes smooth muscle cell migration and proliferation.

AIMS: Ischaemic heart disease is a leading cause of mortality. After ischaemic injury, tissue hypoxia induces the activity of angiogenic factors that promote revascularization. Increased understanding of hypoxia-responsive genes and their role in angiogenesis will lead to new therapies for ischaemic injury. We delineated the function of Canopy 2 (CNPY2), a newly discovered, hypoxia-regulated gene. METHODS AND RESULTS: We found CNPY2 in a screen for genes induced by low oxygen in human smooth muscle cells (SMCs). CNPY2 protein co-localized with the endoplasmic reticulum and the Golgi. Treatment with Brefeldin A, which destroys Golgi stacks, resulted in CNPY2 accumulation in the endoplasmic reticulum. Secreted CNPY2 was detected in the blood of healthy mice and humans, and the medium of cultured SMCs. SMCs under hypoxia or treated with a prolyl-4-hydroxylase inhibitor stabilized HIF-1α protein and up-regulated CNPY2, while CNPY2 induction was lost after HIF-1α silencing. Chromatin immunoprecipitation demonstrated that HIF-1α binds to a hypoxia response element (HRE-1157) upstream of the human CNPY2 promoter, which was verified by a luciferase reporter driven by HRE-1157-containing constructs. CNPY2 stimulation activated Cdc42, PAK1, and FAK in SMCs, resulting in enhanced proliferation and migration in vitro, and dramatic aortic ring sprouting ex vivo. CNPY2 significantly increased revascularization of the mouse retina after reperfusion injury. CONCLUSIONS: CNPY2 is a HIF-1α-regulated, secreted angiogenic growth factor that promotes SMC migration, proliferation, and tissue revascularization. This new target may have a broader profile than currently available proteins.