Cardiac Nerve Growth Factor Overexpression Induces Bone Marrow-derived Progenitor Cells Mobilization and Homing to the Infarcted Heart

Stem cell-based therapy in cardiac repair after myocardial infarction: Promise, challenges, and future directions

Stem cells represent an attractive resource for cardiac regeneration. However, the survival and function of transplanted stem cells is poor and remains a major challenge for the development of effective therapies. As two main cell types currently under investigation in heart repair, mesenchymal stromal cells (MSCs) indirectly support endogenous regenerative capacities after transplantation, while induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) functionally integrate into the damaged myocardium and directly contribute to the restoration of its pump function. These two cell types are exposed to a common microenvironment with many stressors in ischemic heart tissue. This review summarizes the research progress on the mechanisms and challenges of MSCs and iPSC-CMs in post-MI heart repair, introduces several randomized clinical trials with 3D-mapping-guided cell therapy, and outlines recent findings related to the factors that affect the survival and function of stem cells. We also discuss the future directions for optimization such as biomaterial utilization, cell combinations, and intravenous injection of engineered nucleus-free MSCs.

EPO regulates the differentiation and homing of bone marrow mesenchymal stem cells through Notch1/Jagged pathway to treat pulmonary hypertension

Purpose

To investigate whether erythropoietin (EPO) can treat pulmonary arterial hypertension (PAH) in rats by regulating the differentiation and homing of bone marrow mesenchymal stem cells (BMSCs) through Notch1/Jagged signaling pathway.

Materials & methods

BMSCs were isolated from the bone marrow of 6-week-old male SD rats by whole bone marrow method and identified. BMSCs were treated with 500 IU/mL EPO, and the proliferation, migration, invasion and differentiation ability, and the expression of MMP-2 and MMP-9 protein of BMSCs were detected in vitro. After the establishment of the pulmonary hypertension model in rats, BMSCs were intervened with different concentrations of EPO and injected into the rats through intravenous injection. The levels of TNF-α, IL-1β and IL-6 in lung tissue, the expression of SRY CXCR4, CCR2, Notch1 and Jagged protein in lung tissue, and the levels of TGF-α, vascular endothelial factor (VEGF), IGF-1 and HGF in serum were detected. Immunofluorescence (IF) staining was used to detect the co-localization of CD34.

Results

EPO promoted the proliferation, migration, and invasion of BMSCs by inhibiting Notch1/Jagged pathway in vitro, and induced BMSCs to differentiate into vascular smooth muscle cells and vascular endothelial cells. EPO inhibited Notch1/Jagged pathway in PAH rats, induced BMSCs homing and differentiation, increased the levels of TGF-α, VEGF, IGF-1 and HGF, and decreased the levels of TNF-α, IL-1β and IL-6.

Discussion & conclusion

EPO can inhibit the Notch1/Jagged pathway and promote the proliferation, migration, invasion, homing and differentiation of BMSCs to treat pulmonary hypertension in rats in vitro and in vivo.

Hepatobiliary organoids differentiated from hiPSCs relieve cholestasis-induced liver fibrosis in nonhuman primates

There is an urgent need for novel therapies to treat end-stage liver disease due to the shortage of available organs. Although cell transplantation holds considerable promise, its availability is limited due to the low engrafted cell mass and lack of unifying cell transplantation strategies. Here, we optimally established human induced pluripotent stem cell-derived functional hepatobiliary organoids (HBOs) based on our previous research and transplanted them into a monkey model via liver subcapsular and submesenteric transplantation routes to assess their potential clinical application. Our study revealed that HBO transplantation could safely and effectively improve hepatoprotection effects by antiapoptotic and antifibrotic agents. In addition, we also discovered that while multiple HBO transplantation pathways may have a shared effector mechanism, their respective treatment approaches have distinct advantages. Transplantation of HBOs could promote the high expression of CTSV in hepatic sinusoid endothelial cells, which might halt the progression of hepatic sinusoidal capillarization and liver fibrosis. Liver subcapsular transplants had stronger pro-CTSV upregulation than HBO submesenteric transplants, which could be attributed to naturally high CTSV expression in HBOs. Interestingly, both transplantation routes of HBOs were targeted the injured liver and triggered a new pattern of ductular reaction to alleviate the degree of liver fibrosis by surrounding the area with CK19-positive labeled cells. These residing, homing and repairing effects might be related to the high expression of MMP family genes. By promoting a unique pattern of ductular reactions, submesenteric HBO transplantation has a more representative antifibrotic impact than liver subcapsular transplantation. Altogether, our data strongly imply that the treatment of severe liver diseases with liver subcapsular and submesenteric transplantation of HBOs may be clinically effective and safe. These findings provide new insight into HBOs for further experimental and clinical validation.

TrkA specific signalling pathways are critical for mechanical allodynia development and bone alterations in a mouse model of rheumatoid arthritis

ABSTRACT

Rheumatoid arthritis is frequently associated with chronic pain that still remains difficult to treat. Targeting nerve growth factor (NGF) seems very effective to reduce pain in at least, osteoarthritis and chronic low back pain but leads to some potential adverse events. Our aim was to better understand the involvement of the intracellular signalling pathways activated by NGF through its specific tyrosine kinase type A (TrkA) receptor in the pathophysiology of rheumatoid arthritis using the complete Freund adjuvant model in our knock-in TrkA/C mice. Our multimodal study demonstrated that knock-in TrkA/C mice exhibited a specific decrease of mechanical allodynia, weight bearing deficit, peptidergic (CGRP+) and sympathetic (TH+) peripheral nerve sprouting in the joints, a reduction in osteoclast activity and bone resorption markers, and a decrease of CD68 positive cells in the joint with no apparent changes in joint inflammation compared to WT mice following arthritis. Finally, transcriptomic analysis show several differences in DRGs mRNA expression of putative mechanotransducers such as ASIC3 and TRAAK as well as intracellular pathways such as c-Jun in the joint/DRGs. These results suggest that TrkA specific intracellular signalling pathways are specifically involved in mechanical hypersensitivity and bone alterations following arthritis using TrkA/C mice.

Apocynin prevents reduced myocardial nerve growth factor, contributing to amelioration of myocardial apoptosis and failure

Reduced nerve growth factor (NGF) is associated with cardiac sympathetic nerve denervation in heart failure (HF) which is characterized by increased oxidative stress. Apocynin is considered an antioxidant agent which inhibits NADPH oxidase activity and improves reactive oxygen species scavenging. However, it is unclear whether apocynin prevents reduced myocardial NGF, leading to improvement of cardiac function in HF. In this study, we tested the hypothesis that apocynin prevents reduced myocardial NGF, contributing to amelioration of myocardial apoptosis and failure. Rabbits with myocardial infarction (MI) or sham operation were randomly assigned to receive apocynin or placebo for 4 weeks. MI rabbits exhibited left ventricular (LV) dysfunction, and elevation in oxidative stress, as evidenced by a decreased reduced-to-oxidized glutathione ratio and an increased 4-hydroxynonenal expression, and reduction in NGF and NGF receptor tyrosine kinase A (TrKA) expression in the remote non-infarcted myocardium. Apocynin treatment ameliorated LV dysfunction, reduced oxidative stress, prevented decreases in NGF and TrKA expression and reduced cardiomyocyte apoptosis after MI. In cultured H9C2 cardiomyocytes, hypoxia or hydrogen peroxide decreased NGF expression, and apocynin normalized hypoxia-induced reduction of NGF. Recombinant NGF attenuated hypoxia-induced apoptosis. Apocynin prevented hypoxia-induced apoptosis, and the suppressive effect of apocynin on apoptosis was abolished by NGF receptor TrKA inhibitor K252a. We concluded that apocynin prevented reduced myocardial NGF, leading to attenuation of cardiomyocyte apoptosis and LV remodelling and dysfunction in HF after MI. These findings suggest that strategies to prevent NGF reduction by inhibition of oxidative stress may be of value in amelioration of LV dysfunction in HF.

Precision medicine in distinct heart failure phenotypes: Focus on clinical epigenetics

Heart failure (HF) management is challenging due to high clinical heterogeneity of this disease which makes patients responding differently to evidence-based standard therapy established by the current reductionist approach. Better understanding of the genetic and epigenetic interactions may clarify molecular signatures underlying maladaptive responses in HF, including metabolic shift, myocardial injury, fibrosis, and mitochondrial dysfunction. DNA methylation, histone modifications and micro-RNA (miRNAs) may be major epigenetic players in the pathogenesis of HF. DNA hypermethylation of the kruppel-like factor 15 (KLF15) gene plays a key role in switching the failing heart from oxidative to glycolytic metabolism. Moreover, hypomethylation at H3K9 promoter level of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) genes also leads to reactivation of fetal genes in man. The role of miRNAs has been investigated in HF patients undergoing heart transplantation, for whom miR-10a, miR-155, miR-31, and miR-92 may be putative useful prognostic biomarkers. Recently, higher RNA methylation levels have been observed in ischemic human hearts, opening the era of "epitranscriptome" in the pathogenesis of HF. Currently, hydralazine, statins, apabetalone, and omega-3 polyunsatured fatty acids (PUFA) are being tested in clinical trials to provide epigenetic-driven therapeutic interventions. Moreover, network-oriented analysis could advance current medical practice by focusing on protein-protein interactions (PPIs) perturbing the "cardiac" interactome. In this review, we provide an epigenetic map of maladaptive responses in HF patients. Furthermore, we propose the "EPi-transgeneratIonal network mOdeling for STratificatiOn of heaRt Morbidity" (EPIKO-STORM), a clinical research strategy offering novel opportunities to stratify the natural history of HF.

N-Cadherin Overexpression Mobilizes the Protective Effects of Mesenchymal Stromal Cells Against Ischemic Heart Injury Through a β-Catenin-Dependent Manner

RATIONALE

Mesenchymal stromal cell-based therapy is promising against ischemic heart failure. However, its efficacy is limited due to low cell retention and poor paracrine function. A transmembrane protein capable of enhancing cell-cell adhesion, N-cadherin garnered attention in the field of stem cell biology only recently.

OBJECTIVE

The current study investigates whether and how N-cadherin may regulate mesenchymal stromal cells retention and cardioprotective capability against ischemic heart failure.

METHODS AND RESULTS

Adult mice-derived adipose tissue-derived mesenchymal stromal cells (ADSC) were transfected with adenovirus harboring N-cadherin, T-cadherin, or control adenovirus. CM-DiI-labeled ADSC were intramyocardially injected into the infarct border zone at 3 sites immediately after myocardial infarction (MI) or myocardial ischemia/reperfusion. ADSC retention/survival, cardiomyocyte apoptosis/proliferation, capillary density, cardiac fibrosis, and cardiac function were determined. Discovery-driven/cause-effect analysis was used to determine the molecular mechanisms. Compared with ADSC transfected with adenovirus-control, N-cadherin overexpression (but not T-cadherin) markedly increased engrafted ADSC survival/retention up to 7 days post-MI. Histological analysis revealed that ADSC transfected with adenovirus-N-cadherin significantly preserved capillary density and increased cardiomyocyte proliferation and moderately reduced cardiomyocyte apoptosis 3 days post-MI. More importantly, ADSC transfected with adenovirus-N-cadherin (but not ADSC transfected with adenovirus-T-cadherin) significantly increased left ventricular ejection fraction and reduced fibrosis in both MI and myocardial ischemia/reperfusion mice. In vitro experiments demonstrated that N-cadherin overexpression promoted ADSC-cardiomyocyte adhesion and ADSC migration, enhancing their capability to increase angiogenesis and cardiomyocyte proliferation. MMP (matrix metallopeptidases)-10/13 and HGF (hepatocyte growth factor) upregulation is responsible for N-cadherin's effect upon ADSC migration and paracrine angiogenesis. N-cadherin overexpression promotes cardiomyocyte proliferation by HGF release. Mechanistically, N-cadherin overexpression significantly increased N-cadherin/β-catenin complex formation and active β-catenin levels in the nucleus. β-catenin knockdown abolished N-cadherin overexpression-induced MMP-10, MMP-13, and HGF expression and blocked the cellular actions and cardioprotective effects of ADSC overexpressing N-cadherin.

CONCLUSIONS

We demonstrate for the first time that N-cadherin overexpression enhances mesenchymal stromal cells-protective effects against ischemic heart failure via β-catenin-mediated MMP-10/MMP-13/HGF expression and production, promoting ADSC/cardiomyocyte adhesion and ADSC retention.

Useful applications of growth factors for cardiovascular regenerative medicine

Novel advances for cardiovascular diseases (CVDs) include regenerative approaches for fibrosis, hypertrophy, and neoangiogenesis. Studies indicate that growth factor (GF) signaling could promote heart repair since most of the evidence is derived from preclinical models. Observational studies have evaluated GF serum/plasma levels as feasible biomarkers for risk stratification of CVDs. Noteworthy, two clinical interventional published studies showed that the administration of growth factors (GFs) induced beneficial effect on left ventricular ejection fraction (LVEF), myocardial perfusion, end-systolic volume index (ESVI). To date, large scale ongoing studies are in Phase I-II and mostly focussed on intramyocardial (IM), intracoronary (IC) or intravenous (IV) administration of vascular endothelial growth factor (VEGF) and fibroblast growth factor-23 (FGF-23) which result in the most investigated GFs in the last 10 years. Future data of ongoing randomized controlled studies will be crucial in understanding whether GF-based protocols could be in a concrete way effective in the clinical setting.

Impaired Regeneration Contributes to Poor Outcomes in Diabetic Peripheral Artery Disease

Diabetes mellitus increases the risk and accelerates the course of peripheral artery disease, making patients more susceptible to ischemic events and infections and delaying tissue healing. Current understanding of pathogenic mechanisms is mainly based on the negative influence of diabetes mellitus on atherosclerotic disease and inflammation. In recent years, the novel concept that diabetes mellitus can impinge on endogenous regenerative processes has been introduced. Diabetes mellitus affects regeneration at the local level, disturbing proper angiogenesis, collateral artery formation, and muscle repair. Recent evidence indicates that an impairment in vascular mural cells, alias pericytes, may participate in diabetic peripheral vasculopathy. Moreover, the bone marrow undergoes a global remodeling, consisting of microvessels and sensory neurons rarefaction and fat accumulation, which creates a hostile microenvironment for resident stem cells. Bone marrow remodeling is also responsible for detrimental systemic effects. In particular, the aid of reparative cells from the bone marrow is compromised: these elements are released in an improper manner and become harmful vectors of inflammatory and antiangiogenic molecules and noncoding RNAs. This new understanding of impaired regeneration is inspiring new therapeutic options for the treatment of ischemic complications in people with diabetes mellitus.

Nerve growth factor gene therapy improves bone marrow sensory innervation and nociceptor-mediated stem cell release in a mouse model of type 1 diabetes with limb ischaemia

AIMS/HYPOTHESIS

Sensory neuropathy is common in people with diabetes; neuropathy can also affect the bone marrow of individuals with type 2 diabetes. However, no information exists on the state of bone marrow sensory innervation in type 1 diabetes. Sensory neurons are trophically dependent on nerve growth factor (NGF) for their survival. The aim of this investigation was twofold: (1) to determine if sensory neuropathy affects the bone marrow in a mouse model of type 1 diabetes, with consequences for stem cell liberation after tissue injury; and (2) to verify if a single systemic injection of the NGF gene exerts long-term beneficial effects on these phenomena.

METHODS

A mouse model of type 1 diabetes was generated in CD1 mice by administration of streptozotocin; vehicle was administered to non-diabetic control animals. Diabetic animals were randomised to receive systemic gene therapy with either human NGF or β-galactosidase. After 13 weeks, limb ischaemia was induced in both groups to study the recovery post injury. When the animals were killed, samples of tissue and peripheral blood were taken to assess stem cell mobilisation and homing, levels of substance P and muscle vascularisation. An in vitro cellular model was adopted to verify signalling downstream to human NGF and related neurotrophic or pro-apoptotic effects. Normally distributed variables were compared between groups using the unpaired Student's t test and non-normally distributed variables were assessed by the Wilcoxon-Mann-Whitney test. The Fisher's exact test was employed for categorical variables.

RESULTS

Immunohistochemistry indicated a 3.3-fold reduction in the number of substance P-positive nociceptive fibres in the bone marrow of type 1 diabetic mice (p < 0.001 vs non-diabetic). Moreover, diabetes abrogated the creation of a neurokinin gradient which, in non-diabetic mice, favoured the mobilisation and homing of bone-marrow-derived stem cells expressing the substance P receptor neurokinin 1 receptor (NK1R). Pre-emptive gene therapy with NGF prevented bone marrow denervation, contrasting with the inhibitory effect of diabetes on the mobilisation of NK1R-expressing stem cells, and restored blood flow recovery from limb ischaemia. In vitro hNGF induced neurite outgrowth and exerted anti-apoptotic actions on rat PC12 cells exposed to high glucose via activation of the canonical neurotrophic tyrosine kinase receptor type 1 (TrkA) signalling pathway.

CONCLUSIONS/INTERPRETATION

This study shows, for the first time, the occurrence of sensory neuropathy in the bone marrow of type 1 diabetic mice, which translates into an altered modulation of substance P and depressed release of substance P-responsive stem cells following ischaemia. NGF therapy improves bone marrow sensory innervation, with benefits for healing on the occurrence of peripheral ischaemia. Nociceptors may represent a new target for the treatment of ischaemic complications in diabetes.

Resistin promotes cardiac homing of mesenchymal stem cells and functional recovery after myocardial ischemia-reperfusion via the ERK1/2-MMP-9 pathway

Stem cell therapy is a potentially effective and promising treatment for ischemic heart disease. Resistin, a type of adipokine, has been found to bind to adipose-derived mesenchymal stem cells (ADSCs). However, the effects of resistin on cardiac homing by ADSCs and on ADSC-mediated cardioprotective effects have not been investigated. ADSCs were obtained from enhanced green fluorescent protein transgenic mice. C57BL/6J mice were subjected to myocardial ischemia-reperfusion (I/R) or sham operations. Six hours after the I/R operation, mice were intravenously injected with resistin-treated ADSCs (ADSC-resistin) or vehicle-treated ADSCs (ADSC-vehicle). Cardiac homing by ADSCs and cardiomyocyte apoptosis were investigated 3 days after I/R. Cardiac function, fibrosis, and angiogenesis were evaluated 4 wk after I/R. Cellular and molecular mechanisms were investigated in vitro using cultured ADSCs. Both immunostaining and flow cytometric experiments showed that resistin treatment promoted ADSC myocardial homing 3 days after intravenous injection. Echocardiographic experiments showed that ADSC-resistin, but not ADSC-vehicle, significantly improved left ventricular ejection fraction. ADSC-resistin transplantation significantly mitigated I/R-induced fibrosis and reduced atrial natriuretic peptide/brain natriuretic peptide mRNA expression. In addition, cardiomyocyte apoptosis was reduced, whereas angiogenesis was increased by ADSC-resistin treatment. At the cellular level, resistin promoted ADSC proliferation and migration but did not affect H2O2-induced apoptosis. Molecular experiments identified the ERK1/2-matrix metalloproteinase-9 pathway as a key component mediating the effects of resistin on ADSC proliferation and migration. These results demonstrate that resistin can promote homing of injected ADSCs into damaged heart tissue and stimulate functional recovery, an effect mediated through the ERK1/2 signaling pathway and matrix metalloproteinase-9.

NEW & NOTEWORTHY First, intravenous injection of adipose-derived mesenchymal stem cells (ADSCs) treated with resistin significantly increased angiogenesis and reduced myocardial apoptosis and fibrosis in a murine model of ischemia-reperfusion, resulting in improved cardiac performance. Second, resistin treatment significantly increased myocardial homing of intravenously delivered ADSCs. Finally, the ERK1/2-matrix metalloproteinase 9 pathway contributed to the higher proliferative and migratory capacities of ADSCs treated with resistin.

Sphingosine 1-phosphate promotes mesenchymal stem cell-mediated cardioprotection against myocardial infarction via ERK1/2-MMP-9 and Akt signaling axis

AIMS

The sphingolipid metabolite sphingosine 1‑phosphate (S1P) has emerged as a potential cardioprotective molecule against ischemic heart disease. Moreover, S1P triggers mobilization and homing of bone marrow-derived stem/progenitor cells into the damaged heart. However, it remains elusive whether S1P promotes mesenchymal stem cells (MSCs)-mediated cardioprotection against ischemic heart diseases.

MAIN METHODS

Adipose tissue-derived MSCs (AT-MSCs) were obtained from GFP transgenic mice or C57BL/6J. Myocardial infarction (MI) was induced in C57BL/6J mice by ligation of the left anterior descending coronary artery (LAD). Subsequently, S1P-treated AT-MSCs or vehicle-treated AT-MSCs were intravenously administered for 24 h after induction of MI or sham procedure.

KEY FINDINGS

Pre-conditioning with S1P significantly enhanced the migratory and anti-apoptotic efficacies of AT-MSCs. In MI-induced mice, intravenous administration of S1P-treated AT-MSCs significantly augmented their homing and engraftment in ischemic area. Besides, AT-MSCs with S1P pre-treatment exhibited enhanced potencies to inhibit cardiomyocyte apoptosis and fibrosis, and stimulate angiogenesis and preserve cardiac function. Mechanistic studies revealed that S1P promoted AT-MSCs migration through activation of ERK1/2-MMP-9, and protected AT-MSCs against apoptosis via Akt activation. Further, S1P activated the ERK1/2 and Akt via S1P receptor 2 (S1PR2), but not through S1PR1. S1PR2 knockdown by siRNA, however, significantly attenuated S1P-mediated AT-MSCs migration and anti-apoptosis.

SIGNIFICANCE

The findings of the present study revealed the protective efficacies of S1P pretreatment on the survival/retention and cardioprotection of engrafted MSCs. Pre-conditioning of donor MSCs with S1P is an effective strategy to promote the therapeutic potential of MSCs for ischemic heart diseases.

Stem Cell Homing: a Potential Therapeutic Strategy Unproven for Treatment of Myocardial Injury

Despite advances in the prevention and therapeutic modalities of ischemic heart disease, morbidity and mortality post-infarction heart failure remain big challenges in modern society. Stem cell therapy is emerging as a promising therapeutic strategy. Stem cell homing, the ability of stem cells to find their destination, is receiving more attention. Identification of specific cues and understanding the signaling pathways that direct stem cells to targeted destination will improve stem cell homing efficiency. This review discusses the cellular and molecular mechanism of stem cell homing at length in the light of literature and analyzes the problem and considerations of this approach as a treatment strategy for the treatment of ischemic heart disease clinically.

Chemokines and Heart Disease: A Network Connecting Cardiovascular Biology to Immune and Autonomic Nervous Systems

Among the chemokines discovered to date, nineteen are presently considered to be relevant in heart disease and are involved in all stages of cardiovascular response to injury. Chemokines are interesting as biomarkers to predict risk of cardiovascular events in apparently healthy people and as possible therapeutic targets. Moreover, they could have a role as mediators of crosstalk between immune and cardiovascular system, since they seem to act as a “working-network” in deep linkage with the autonomic nervous system. In this paper we will describe the single chemokines more involved in heart diseases; then we will present a comprehensive perspective of them as a complex network connecting the cardiovascular system to both the immune and the autonomic nervous systems. Finally, some recent evidences indicating chemokines as a possible new tool to predict cardiovascular risk will be described.