Enriched human embryonic stem cells-derived CD133+, CD24+ renal progenitors engraft and restore function in a gentamicin-induced kidney injury in mice.

Introduction: Acute kidney injury (AKI) is a common health problem that leads to high morbidity and potential mortality. The failure of conventional treatments to improve forms of this condition highlights the need for innovative and effective treatment approaches. Regenerative therapies with Renal Progenitor Cells (RPCs) have been proposed as a promising new strategy. A growing body of evidence suggests that progenitor cells differentiated from different sources, including human embryonic stem cells (hESCs), can effectively treat AKI. Methods: Here, we describe a method for generating RPCs and directed human Embryoid Bodies (EBs) towards CD133+CD24+ renal progenitor cells and evaluate their functional activity in alleviating AKI. Results: The obtained results show that hESCs-derived CD133+CD24+ RPCs can engraft into damaged renal tubules and restore renal function and structure in mice with gentamicin-induced kidney injury, and significantly decrease blood urea nitrogen levels, suppress oxidative stress and inflammation, and attenuate histopathological disturbances, including tubular necrosis, tubular dilation, urinary casts, and interstitial fibrosis. Conclusion: The results suggest that RPCs have a promising regenerative potential in improving renal disease and can lay the foundation for future cell therapy and disease modeling.

Spinal Cord Injury Causes Prominent Tau Pathology Associated with Brain Post-Injury Sequela.

Spinal cord injury (SCI) can result in significant neurological impairment and functional and cognitive deficits. It is well established that SCI results in focal neurodegeneration that gradually spreads to other cord areas. On the other hand, traumatic brain injury (TBI) is strongly associated with tau protein pathology and neurodegeneration that can spread in areas throughout the brain. Tau is a microtubule-associated protein abundant in neurons and whose abnormalities result in neuronal cell death. While SCI and TBI have been extensively studied, there is limited research on the relationship between SCI and brain tau pathology. As a result, in this study, we examined tau pathology in spinal cord and brain samples obtained from severe SCI mouse models at various time points. The effects of severe SCI on locomotor function, spatial memory, anxiety/risk-taking behavior were investigated. Immunostaining and immunoblotting confirmed a progressive increase in tau pathology in the spinal cord and brain areas. Moreover, we used electron microscopy to examine brain samples and observed disrupted mitochondria and microtubule structure following SCI. SCI resulted in motor dysfunction, memory impairment, and abnormal risk-taking behavior. Notably, eliminating pathogenic cis P-tau via systemic administration of appropriate monoclonal antibodies restored SCI's pathological and functional consequences. Thus, our findings suggest that SCI causes severe tauopathy that spreads to brain areas, indicating brain dysfunction. Additionally, tau immunotherapy with an anti-cis P-tau antibody could suppress pathogenic outcomes in SCI mouse models, with significant clinical implications for SCI patients. SCI induces profound pathogenic cis p-tau, which diffuses into the brain through CSF, resulting in brain neurodegeneration and cognitive decline.

Assessment of the Effect of Infliximab on Immunomodulation Properties of Mesenchymal Stem Cells In Vitro.

Purpose: Mesenchymal stem cells (MSCs) have immunomodulatory traits making them a promising choice in the treatment of inflammatory diseases such as graft-versus-host disease (GVHD). Tumor necrosis factor-alpha (TNFα) is a major player of inflammatory disease which is blocked by infliximab to reduce the inflammation. The present study aims to assess the infliximab effects on the anti-inflammatory properties of MSCs. Methods: In this study, bone marrow mesenchymal stem cells (BMMSCs) were co-cultured with peripheral blood mononuclear cells (PBMCs) of GVHD patients in the presence of 10, 20 and 30 µg/mL of infliximab for 48 and 72 hours. The mRNA expression of indoleamine-2,3- dioxygenase (IDO) and inducible nitric oxide synthase (iNOS), as well as the secreted amount of prostaglandin E2 (PGE2) in the culture supernatant, were examined. Results: The results of this study show that the expression of IDO and iNOS genes, as well as the secretion amount of PGE2 in co-cultured groups raised dramatically, compared to the culture of BMMSCs or PBMCs alone. In co-culture groups containing infliximab, the expression of IDO and iNOS and also the amount of released PGE2 was significantly decreased compared to the control group without infliximab. However, no difference was found in the expression of assayed factors between 48 and 72 hours of treatments. Conclusion: As an anti-TNFα agent, infliximab can decrease the inflammation in the microenvironment of MSCs, which might mitigate the immunomodulatory effects of MSCs. These effects of anti-inflammatory agents on the immunomodulatory capacity of MSCs should be considered in MSC therapy.

Immunomodulatory Activity of Human Bone Marrow and Adipose-Derived Mesenchymal Stem Cells Prolongs Allogenic Skin Graft Survival in Nonhuman Primates.

OBJECTIVE: In the present study, we examined the tolerance-inducing effects of human adipose-derived mesenchymal stem cells (hAD-MSCs) and bone marrow-derived MSCs (hBM-MSCs) on a nonhuman primate model of skin transplantation. MATERIALS AND METHODS: In this experimental study, allogenic and xenogeneic of immunomodulatory properties of human AD-MSCs and BM-MSCs were evaluated by mixed lymphocyte reaction (MLR) assays. Human MSCs were obtained from BM or AD tissues (from individuals of either sex with an age range of 35 to 65 years) and intravenously injected (2×106 MSCs/kg) after allogeneic skin grafting in a nonhuman primate model. The skin sections were evaluated by H and E staining for histopathological evaluations, particularly inflammation and rejection reaction of grafts after 96 hours of cell injection. At the mRNA and protein levels, cellular mediators of inflammation, such as CD4+IL-17+ (T helper 17; Th17) and CD4+INF-γ+ (T helper 1, Th1) cells, along with CD4+FoxP3+ cells (Treg), as the mediators of immunomodulation, were measured by RT-PCR and flow cytometry analyses. RESULTS: A significant Treg cells expansion was observed in MSCs-treated animals which reached the zenith at 24 hours and remained at a high concentration for 96 hours; however, Th1 and Th17 cells were significantly decreased. Our results showed that human MSCs significantly decrease Th1 and Th17 cell proliferation by decreasing interleukin-17 (IL-17) and interferon-γ (INF-γ) production and significantly increase Treg cell proliferation by increasing FoxP3 production. They also extend the allogenic skin graft survival in nonhuman primates. Histological evaluations showed no obvious presence of inflammatory cells or skin redness or even bulging after MSCs injection up to 96 hours, compared to the group without MSCs. There were no significant differences between hBM-MSCs and hAD-MSCs in terms of histopathological scores and inflammatory responses (P<0.05). CONCLUSION: It seems that MSCs could be regarded as a valuable immunomodulatory tool to reduce the use of immunosuppressive agents.

Improved differentiation of human enriched CD133+CD24+ renal progenitor cells derived from embryonic stem cell with embryonic mouse kidney-derived mesenchymal stem cells co-culture.

End-stage renal disease (ESRD) is a major global public health issue. In the past decade, regenerative medicine and cell-based therapies were recommended for treatment of devastating diseases like ESRD. Renal progenitor (RP) cells are essential players in such treatment approaches. The major practical difficulties in application of RP cells are generation of these cells and preservation of their self-renewal capacity; also, they should lack identified appropriate cell surface markers. To identify and isolate RP cells, two cell surface markers namely, CD133 and CD24 were recently used. In this study, we used these markers to facilitate selection and purification of RP cells from embryoid bodies (EBs), and assessed the impact of the use of bFGF on frequency of CD133+CD24+ expression in cells presented in EBs. Moreover, following isolation of CD133+CD24+ cells from EBs, we evaluated the effect of embryonic, neonatal and adult mouse kidney-derived mesenchymal stem cells (E-KMSC, N-KMSC and A-KMSC respectively) and fibronectin on further differentiation of the sorted cells. Hence, we cultured undifferentiated human embryonic stem cells (hESCs) in suspension state in the presence or absence of bFGF and determined maximum number of CD133+CD24+ cells in bFGF-treated EBs on day 7. Then, we tested the effect of E-KMSC co-culture and seeding on fibronectin-coated plated on differentiation of the sorted cells into renal epithelial cells. Results revealed down-regulation of several RP cells, markers in CD133+CD24+ cells. In contrast, renal epithelial marker gene expressions were up-regulated after 7 days of co-culture with E-KMSC. Furthermore, fibronectin resulted in higher expression of renal epithelial markers compared to the E-KMSC co-cultured cells. All in all, bFGF could enhance the number of RP cells expressing CD133 and CD24 markers, in human EBs. We suggest E-KMSC and fibronectin as a promising supplementary factor to further induce differentiation of RP cells into renal epithelial cells.

cis pT231-Tau Drives Neurodegeneration in Bipolar Disorder.

Bipolar disorder is a complex neuropsychiatric disorder, characterized by intermittent episodes of mania and depression. Recent studies have indicated argyrophilic grains, composed of hyperphosphorylated tau, are observable in postmortem brains of bipolar patients. It remains uncertain how tau hyperphosphorylation results in neurodegeneration upon the disease. Recent studies have demonstrated that phosphorylated tau at Thr231 exists in two distinct cis and trans conformations, in which cis pT231-tau is highly neurotoxic and acts as an early driver of tauopathy in several neurodegenerative diseases. We herein employed an in vitro model, which resembles some aspects of bipolar disorder, to study the cis p-tau mediatory role. We established GSK3ß overexpressing SH-SY5Y cells and examined cell viability, cis p-tau formation, and lithium effects by immunofluorescence and flow cytometry. We found an increase in cis p-tau levels as well as viability decrease in the cell model. Furthermore, we discovered that lithium treatment inhibits cis p-tau formation, resulting in diminished cell death. We also examined BD and healthy human brain samples and detected cis p-tau in the patients' brains. Our results show that tauopathy, observed in bipolar disorder, is being mediated through cis p-tau and that a conformer could be the cause of neurodegeneration upon the disease. Our findings would suggest novel therapeutic target to fight the devastating disorder.

Stem cell therapy in Alzheimer's disease: possible benefits and limiting drawbacks.

Alzheimer's disease (AD) is the sixth leading cause of death globally and the main reason for dementia in elderly people. AD is a long-term and progressive neurodegenerative disorder that steadily worsens memory and communicating skills eventually leads to a disabled person of performing simple daily tasks. Unfortunately, numerous clinical trials exploring new therapeutic drugs have encountered disappointing outcomes in terms of improved cognitive performance since they are not capable of halting or stimulating the regeneration of already-damaged neural cells, and merely provide symptomatic relief. Therefore, a deeper understanding of the mechanism of action of stem cell may contribute to the development of novel and effective therapies. The revolutionary discovery of stem cells has cast a new hope for the development of disease-modifying treatments for AD, in terms of their potency in the replenishment of lost cells via differentiating towards specific lineages, stimulating in situ neurogenesis, and delivering the therapeutic agents to the brain. Herein, firstly, we explore the pathophysiology of AD. Next, we summarize the most recent preclinical stem cell reports designed for AD treatment, their benefits and outcomes according to cell type. We briefly review relevant clinical trials and their potential clinical applications in order to find a unique solution to effectively relieve the patients' pain.