TLR3 stimulation improves the migratory potency of adipose-derived mesenchymal stem cells through the stress response pathway in the melanoma mouse model.

BACKGROUND: Mesenchymal stem cells (MSCs) are utilized as a carrier of anti-tumor agents in targeted anti-cancer therapy. Despite the improvements in this area, there are still some unsolved issues in determining the appropriate dose, method of administration and biodistribution of MSCs. The current study aimed to determine the influence of toll-like receptor 3 (TLR3) stimulation on the potential of MSCs migration to the neoplasm environment in the mouse melanoma model. METHODS AND RESULTS: Adipose-derived MSCs (ADMSCs) were isolated from the GFP+ transgenic C57BL/6 mouse and treated with different doses (1 µg/ml and 10 µg/ml) of polyinosinic-polycytidylic acid, the related TLR3 agonist, at various time points (1 and 4 h). Following the treatment, the expression of targeted genes such as α4, α5, and ß1 integrins and TGF-ß and IL-10 anti-inflammatory cytokines was determined using real-time PCR. In vivo live imaging evaluated the migration index of the intraperitoneally (IP) injected treated ADMSCs in a lung tumor-bearing mouse (C57BL/6) melanoma model (n = 5). The presented findings demonstrated that TLR3 stimulation enhanced both migration of ADMSCs to the tumor area compared with control group (n = 5) and expression of α4, α5, and ß1 integrins. It was also detected that the engagement of TLR3 resulted in the anti-inflammatory behavior of the cells, which might influence the directed movement of ADMSCs. CONCLUSION: This research identified that TLR3 activation might improve the migration via the stimulation of stress response in the cells and depending on the agonist concentration and time exposure, this activated pathway drives the migratory behavior of MSCs.

The effect of poly I:C or LPS priming on the therapeutic efficacy of mesenchymal stem cells in an adjuvant-induced arthritis rat model.

BACKGROUND: The immunomodulatory properties of mesenchymal stem cells (MSCs) have made them a prospective treatment option for inflammatory and autoimmune disorders. Recent studies have found an association between the immunomodulatory function of MSCs and Toll-like receptors (TLRs). Here, we investigated the effect of priming with lipopolysaccharide (LPS) as TLR4 ligand or polyinosinic:polycytidylic acid (poly I:C) as TLR3 ligand on the immunomodulatory function of adipose-derived MSCs (ADMSCs) in vitro and for the first time in an adjuvant-induced arthritis model (AIA). METHODS: ADMSCs were treated with LPS or poly I:C for 1 h. Splenocyte proliferation in the presence of primed ADMSCs was assessed in vitro using an MTT assay. Next, we investigated the therapeutic effect of primed ADMSCs in vivo. Male Wistar rats were infused with complete Freund's adjuvant (CFA) to develop arthritis and then intraperitoneally treated with not-primed, poly I:C- or LPS-primed ADMSCs. Clinical signs, histopathological alteration, and serum and spleen cytokine levels were analyzed. RESULTS: Poly I:C-primed ADMSCs significantly reduced splenocytes proliferation, while ADMSCs primed with LPS increased splenocytes proliferation. Furthermore, poly I:C-primed ADMSCs significantly alleviated the clinical and histopathological severity and the secretion of inflammatory cytokines associated with Th17/Th1 such as IL-17 and IFN-γ. Poly I:C-primed ADMSCs also increased cytokines IL-10 and TGF-ß. TNF-α and IL-6 Levels were also markedly diminished in the serum of AIA animals treated with poly I:C-primed ADMSCs. In contrast, priming ADMSCs with LPS significantly reduced the therapeutic effect of ADMSCs in AIA animals. CONCLUSION: As a result of these findings, poly I:C priming may be a new technique for improving the therapeutic effects of MSCs in arthritic disorders.

Transplantation of decellularised human amniotic membranes seeded with mesenchymal stem cell-educated macrophages into animal models.

The reconstruction of chronic skin wounds remains a public health challenge in dermatology. Precisely controlling and monitoring the wound-healing process should result in enhanced outcomes for the patient. Cell-based therapies have shown great potential in medicine due to their immunomodulatory and healing properties. Herein, we produced activated macrophages by treating circulating monocytes with mesenchymal stem cell (MSC) supernatant. We also demonstrated the critical role of activated macrophages transplantation using amniotic membranes in accelerating wound healing in an animal wound model. The activated macrophages not only exhibited immunomodulatory cytokines like transforming growth factorß (TGFß) and interleukin 10 (and IL10) secretion but also showed attachment and proliferation ability on the amniotic membrane scaffold. Moreover, MSCs supernatant-treated cells also displayed significant ARG1, CD206, and IL 10 genes expression. Inspired by the in vitro results, we examined the in vivo therapeutic efficacy of the activated macrophage transplantation using an acellular amniotic membrane carrier in a full-thickness cutaneous wound model. The wound healing rate was significant in the group treated with macrophages generated via mesenchymal cell therapy seeded human amniotic membrane. There was less scarring in the wound sites after placing cell-scaffold constructs in the wound sites in the animal models. Overall, macrophages stimulated with mesenchymal cells' supernatant exhibited improved healing processes in incisional wounds by decreasing the inflammatory phase, increasing angiogenesis, and reducing scar tissue development.

Possible involvement of ATP-sensitive potassium channels in the antidepressant-like effects of gabapentin in mouse forced swimming test.

Gabapentin as an anticonvulsant drug also has beneficial effects in treatment of depression. Previously, we showed that acute administration of gabapentin produced an antidepressant-like effect in the mouse forced swimming test (FST) by a mechanism that involves the inhibition of nitric oxide (NO). Considering the involvement of NO in adenosine triphosphate (ATP)-sensitive potassium channels (KATP), in the present study we investigated the involvement of KATP channels in antidepressant-like effect of gabapentin. Gabapentin at different doses (5-10 mg/kg) and fluoxetine (20 mg/kg) were administrated by intraperitoneal route, 60 and 30 min, respectively, before the test. To clarify the probable involvement of KATP channels, mice were pretreated with KATP channel inhibitor or opener. Gabapentin at dose 10 mg/kg significantly decreased the immobility behavior of mice similar to fluoxetine (20 mg/kg). Co-administration of subeffective dose (1 mg/kg) of glibenclamide (inhibitor of KATP channels) with gabapentin (3 mg/kg) showed a synergistic antidepressant-like effect. Also, subeffective dose of cromakalim (opener of KATP channels, 0.1 mg/kg) inhibited the antidepressant-like effect of gabapentin (10 mg/kg). None of the treatments had any impact on the locomotor movement. Our study, for the first time, revealed that antidepressant-like effect of gabapentin in mice is mediated by blocking the KATP channels.