Polyurethane-based nanofibrous mat containing porphyrin with photosensitivity and bactericidal properties can promote cutaneous tissue healing in rats.

The regeneration of cutaneous tissue is one of the most challenging issues in human regenerative medicine. To date, several studies have been done to promote cutaneous tissue healing with minimum side effects. The healing potential of polyurethane (PU)/Poly (caprolactone)-poly (ethylene glycol)-poly (caprolactone) (PCEC)/chitosan (CS) (PCS) nanofibrous mat with cationic photosensitizer meso tetrakis (N-methyl pyridinium-4-yl) porphyrin tetratosylate salt (TMP) was examined. The CS tripolyphosphate nanoparticles (CSNPs) were prepared and loaded by TMP to provide an efficient drug release system (TMPNPs) for delivery of TMP to promote wound healing. In in vitro setting, parameters such as bactericidal effects, cytocompatibility, and hemolytic effects were examined. The healing potential of prepared nanofibrous mats was investigated in a rat model of full-thickness cutaneous injury. PCS/TMP/TMPNPs nanofibers can efficiently release porphyrin in the aqueous phase. The addition of TMPNPs and CS to the PU backbone increased the hydrophilicity, degradation, and reduced mechanical properties. The culture of human fetal foreskin fibroblasts (HFFF2) on PCS/TMP/TMPNPs scaffold led to an increased survival rate and morphological adaptation analyzed by MTT and SEM images. Irradiation with a red laser (635 nm, 3 J/cm2) for the 30 s reduced viability of S. aureus and E. Coli bacteria plated on PCS/TMP and PCS/TMP/TMPNPs nanofibrous mats compared to PU/PCEC (PC) and PU/PCEC/CS (PCS) groups, indicating prominent antibacterial effects of PCS/TMP and PCS/TMP/TMPNPs nanofibrous (p < 0.05). Data indicated that PCS/TMP/TMPNPs mat enhanced healing of the full-thickness excisional wound in a rat model by the reduction of inflammatory response and fibrotic changes compared to the PC, and PCS groups (p < 0.05). Immunofluorescence imaging indicated that levels of Desmoglein were increased in rats that received PCS/TMP/TMPNPs compared to the other groups. It is found that a PU-based nanofibrous mat is an appropriate scaffold to accelerate the healing of injured skin.

Activation of toll-like receptor signaling in endothelial progenitor cells dictates angiogenic potential: from hypothesis to actual state.

Human endothelial progenitor cells (EPCs) were isolated from cord blood samples and enriched by magnetic activated cell sorting method based on the CD133 marker. Cells were incubated with different doses of bacterial lipopolysaccharide, ranging from 2, 5, 10, 50, 100, 200, 250, 500, to 1000 µg/ml, for 48 h. The cell survival rate was determined by using MTT assay. To confirm activation of the toll-like receptor signaling pathway, PCR array analysis was performed. Protein levels of ERK1/2, p-ERK1/2, NF-ƙB and TRIF proteins were measured using western blotting. The content of TNF-α and lipoprotein lipase activity were analyzed by immunofluorescence imaging. Flow cytometric analysis of CD31 was performed to assess the maturation rate. Cell migration was studied by the Transwell migration assay. The expression of genes related to exosome biogenesis was measured using real-time PCR analysis. In vivo gel plug angiogenesis assay was done in nude mice. Lipopolysaccharide changed endothelial progenitor cells' survival in a dose-dependent manner with maximum viable cells in groups treated with 2 µg/ml. PCR array analysis showed the activation of toll-like signaling pathways after exposure to LPS (p<0.05). Western blotting analysis indicated an induction of p-ERK1/2 and Erk1/2, NF-kB and TRIF in LPS-treated EPCs compared with the control (p<0.05). Immunofluorescence staining showed an elevation of TNF-α and lipoprotein lipase activity after lipopolysaccharide treatment (p<0.05). Lipopolysaccharide increased EPC migration and expression of exosome biogenesis-related genes (p<0.05). In vivo gel plug analysis revealed enhanced angiogenesis in cells exposed to bacterial lipopolysaccharide. Data highlighted the close relationship between the toll-like receptor signaling pathway and functional activity in EPCs.

Mitochondrial donation in translational medicine; from imagination to reality.

The existence of active crosstalk between cells in a paracrine and juxtacrine manner dictates specific activity under physiological and pathological conditions. Upon juxtacrine interaction between the cells, various types of signaling molecules and organelles are regularly transmitted in response to changes in the microenvironment. To date, it has been well-established that numerous parallel cellular mechanisms participate in the mitochondrial transfer to modulate metabolic needs in the target cells. Since the conception of stem cells activity in the restoration of tissues' function, it has been elucidated that these cells possess a unique capacity to deliver the mitochondrial package to the juxtaposed cells. The existence of mitochondrial donation potentiates the capacity of modulation in the distinct cells to achieve better therapeutic effects. This review article aims to scrutinize the current knowledge regarding the stem cell's mitochondrial transfer capacity and their regenerative potential.

Correction to: Low-level laser irradiation at a high power intensity increased human endothelial cell exosome secretion via Wnt signaling.

After publication of this paper, the authors determined an error in Fig. 4. Below is the correct Fig. 4.

Silibinin protects human endothelial cells from high glucose-induced injury by enhancing autophagic response.

Silibin, a flavonoid from the seeds of Silybum marianum (L.) Gaertn. (Asteraceae) has been reported to produce curative properties in diabetes. Autophagy is generated by a vast array of insults for removal of damaged proteins and organelles from the cell. Inadequate autophagy promotes endothelial cells dysfunction and delays in diabetic ulcers recovery. We hypothesized that silibinin could protect endothelial cells against high glucose-induced damage by engaging autophagic responses. HUVECs viability was evaluated by MTT assay. The Griess method and TBARS assay were used to monitor changes in the levels of nitric oxide and malondialdehyde, respectively. ROS generation was recorded in DCFDA-stained cells analyzed by flow cytometry. To investigate the role of silibinin on migration, we used scratch test. The level of autophagy proteins LC3, Becline-1, and P62 were measured by Western blotting. Our data showed that silibinin had potential to increase cell survival after exposure to high glucose condition. Total levels of oxidative stress markers were profoundly reduced and the activity of GSH was increased by silibinin. High glucose suppressed HUVECs migration to the scratched area. However, a significant increase in cell migration was observed after exposure to silibinin. Autophagy was blocked at the late stage by high glucose concentration and silibinin initiated an autophagic response by reducing P62 and enhancing Beclin-1 and LC3-II-LC3-I ratio. These effects were blocked by autophagy inhibitor of 3-Methyladenine. These observations suggest that silibinin could protect HUVECs from high glucose induced-damage possibly by activation of autophagy pathway.

Carvacrol promotes angiogenic paracrine potential and endothelial differentiation of human mesenchymal stem cells at low concentrations.

OBJECTIVES: Phenolic monoterpene compound, named Carvacrol, has been found to exert different biological outcomes. It has been accepted that the angiogenic activity of human mesenchymal stem cells was crucial in the pursuit of appropriate regeneration. In the current experiment, we investigated the contribution of Carvacrol on the angiogenic behavior of primary human mesenchymal stem cells. METHODS: Mesenchymal stem cells were exposed to Carvacrol in a dose ranging from 25 to 200µM for 48h. We measured cell survival rate by MTT assay and migration rate by a scratch test. The oxidative status was monitored by measuring SOD, GPx activity. The endothelial differentiation was studied by evaluating the level of VE-cadherin and vWF by real-time PCR and ELISA analyses. The content of VEGF and tubulogenesis behavior was monitored in vitro. We also conducted Matrigel plug in vivo CAM assay to assess the angiogenic potential of conditioned media from human mesenchymal stem cells after exposure to Carvacrol. RESULTS: Carvacrol was able to increase mesenchymal stem cell survival and migration rate (p<0.05). An increased activity of SOD was obtained while GPx activity unchanged or reduced. We confirmed the endothelial differentiation of stem cells by detecting vWF and VE-cadherin expression (p<0.05). The VEGF expression was increased and mesenchymal stem cells conditioned media improved angiogenesis tube formation in vitro (p<0.05). Moreover, histological analysis revealed an enhanced microvascular density at the site of Matrigel plug in CAM assay. CONCLUSIONS: Our data shed lights on the possibility of a Carvacrol to induce angiogenesis in human mesenchymal stem cells by modulating cell differentiation and paracrine angiogenic response.

Low-level laser irradiation at a high power intensity increased human endothelial cell exosome secretion via Wnt signaling.

The distinct role of low-level laser irradiation (LLLI) on endothelial exosome biogenesis remains unclear. We hypothesize that laser irradiation of high dose in human endothelial cells (ECs) contributes to the modulation of exosome biogenesis via Wnt signaling pathway. When human ECs were treated with LLLI at a power density of 80 J/cm2, the survival rate reduced. The potential of irradiated cells to release exosomes was increased significantly by expressing genes CD63, Alix, Rab27a, and b. This occurrence coincided with an enhanced acetylcholine esterase activity, pseudopodia formation, and reduced zeta potential value 24 h post-irradiation. Western blotting showed the induction of LC3 and reduced level of P62, confirming autophagy response. Flow cytometry and electron microscopy analyses revealed the health status of the mitochondrial function indicated by normal ΔΨ activity without any changes in the transcription level of PINK1 and Optineurin. When cells exposed to high power laser irradiation, p-Akt/Akt ratio and in vitro tubulogenesis capacity were blunted. PCR array and bioinformatics analyses showed the induction of transcription factors promoting Wnt signaling pathways and GTPase activity. Thus, LLLI at high power intensity increased exosome biogenesis by the induction of autophagy and Wnt signaling. LLLI at high power intensity increases exosome biogenesis by engaging the transcription factors related to Wnt signaling and autophagy stimulate.

Functional convergence of Akt protein with VEGFR-1 in human endothelial progenitor cells exposed to sera from patient with type 2 diabetes mellitus.

Diabetes mellitus type 2 predisposes patients to various microvascular complications. In the current experiment, the potent role of diabetes mellitus was investigated on the content of VEGFR-1, -2, Tie-1 and -2, and Akt in human endothelial progenitor cells. The gene expression profile of mTOR and Hedgehog signaling pathways were measured by PCR array. The possible crosstalk between RTKs, mTOR and Hedgehog signaling was also studied by bioinformatic analysis. Endothelial progenitor cells were incubated with serum from normal and diabetic for 7days. Compared to non-treated cells, diabetic serum-induced cell apoptosis (~2-fold) and prohibited cell migration toward bFGF (p<0.001). ELISA analysis showed that diabetes exposed cells had increased abundance of Tie-1, -2 and VEGFR-2 and reduced amount of VEGFR-1 (p<0.0001) in diabetic cells. Western blotting showed a marked reduction in the protein level of Akt after cells exposure to serum from diabetic subjects (p<0.0001). PCR array revealed a significant stimulation of both mTOR and Hedgehog signaling pathways in diabetic cells (p<0.05). According to data from bioinformatic datasets, we showed VEGFR-1, -2 and Tie-2, but not Tie-1, are master regulators of angiogenesis. There is a crosstalk between RTKs and mTOR signaling by involving P62, GABARAPL1, and HTT genes. It seems that physical interaction and co-expression of Akt decreased the level of VEGFR-1 in diabetic cells. Regarding data from the present experiment, diabetic serum contributed to uncontrolled induction of both mTOR and Hedgehog signaling in endothelial progenitor cells. Diabetes mellitus induces mTOR pathway by involving receptor tyrosine kinases while Hedgehog stimulation is independent of these receptors.

Does the Global Outbreak of COVID-19 or Other Viral Diseases Threaten the Stem Cell Reservoir Inside the Body?

The COVID-19 pandemic has profoundly influenced public health and contributed to global economic divergences of unprecedented dimensions. Due to the high prevalence and mortality rates, it is then expected that the consequence and public health challenges will last for long periods. The rapid global spread of COVID-19 and lack of enough data regarding the virus pathogenicity multiplies the complexity and forced governments to react quickly against this pandemic. Stem cells represent a small fraction of cells located in different tissues. These cells play a critical role in the regeneration and restoration of injured sites. Because of their specific niche and a limited number of stem cells, the key question is whether there are different anti-viral mechanisms against viral infection notably COVID-19. Here, we aimed to highlight the intrinsic antiviral resistance in different stem cells against viral infection. These data could help us to understand the possible viral infections in different stem cells and the activation of specific molecular mechanisms upon viral entrance.

Estradiol modulated colorectal cancer stem cells bioactivity and interaction with endothelial cells.

This study aimed to evaluate the modulatory role of sex-related hormone estradiol on cancer stem cells with the origin of colorectal adenocarcinoma in vitro. Cancer stem cells were incubated with 100 nM estradiol for 48 h. The cell survival rate was analyzed using the MTT assay. Immunocytochemistry staining of Ki-67 and Inhibin and Apoptosis PCR array were done to measure proliferation/apoptosis. Cell migration was monitored via the Transwell Migration assay. The expression of exosome biogenesis genes was measured using a real-time PCR assay. The fatty acid profile was monitored using gas chromatography. The level of FAK, SQSTM1, ER, and SIRT1 was examined using Western blotting. Cancer stem-endothelial cell interaction was investigated using Surface Plasmon Resonance assay. Data showed no significant differences in cancer stem cell viability and proliferation between control and estradiol-treated groups (p>0.05). PCR array highlighted the up-regulation of both pro- and anti-apoptosis effectors in the treatment group compared to the control cells (p<0.05). Cell migration capacity was increased after treatment with estradiol (p<0.001). Both exocytosis and exosome biogenesis were decreased in cancer stem cells exposed to estradiol (p<0.05). Data showed the reduction of palmitic acid, and increase of Palmitoleic and Linolenic acids in estradiol-treated cells. Estrogen induced estrogen receptor, SQSTM1 proteins and decreased SIRT1 factor after 48 h. Surface Plasmon Resonance revealed the suppression of cancer stem-endothelial cell interaction and affinity. Estradiol could change the migration, juxtacrine and paracrine activities of cancer stem cells, showing the importance of sex-related hormones in the dynamic of cancer development.

Quercetin promotes learning and memory performance concomitantly with neural stem/progenitor cell proliferation and neurogenesis in the adult rat dentate gyrus.

The decline in neurogenesis is a very critical problem in Alzheimer disease. Different biological activities have been reported for medicinal application of quercetin. Herein, we investigated the neurogenesis potential of quercetin in a rat model of Alzheimer's disease induced by amyloid-beta injection. Rats were randomly divided into Control, Alzheimer + Saline and Alzheimer + Quercetin groups. Following the administration of Amyloid-beta, rats in the Alzheimer + Quercetin group received 40 mg/kg/day quercetin orally for one month. Our data demonstrated amyloid-ß injection could impair learning and memory processing in rats indicated by passive avoidance test evaluation. We noted that one-month quercetin treatment alleviated the detrimental effects of amyloid-ß on spatial learning and memory parameters using Morris water maze analysis. Quercetin was found to increase the number of proliferating neural stem/progenitor cells. Notably, quercetin increased the number of DCX-expressing cells, indicating the active dynamic growth of neural progenitor cells in the dentate gyrus of the hippocampus. We further observed that the quercetin improved the number of BrdU/NeuN positive cells contributed to enhanced adult neurogenesis. Based on our results, quercetin had the potential to promote the expression of BDNF, NGF, CREB, and EGR-1 genes involved in regulating neurogenesis. These data suggest that quercetin can play a valuable role in alleviating Alzheimer's disease symptoms by enhancing adult neurogenesis mechanism.