The Beneficial and Adverse Effects of Autophagic Response to Caloric Restriction and Fasting.

Each cell is equipped with a conserved housekeeping mechanism, known as autophagy, to recycle exhausted materials and dispose of injured organelles via lysosomal degradation. Autophagy is an early-stage cellular response to stress stimuli in both physiological and pathological situations. It is thought that the promotion of autophagy flux prevents host cells from subsequent injuries by removing damaged organelles and misfolded proteins. As a correlate, the modulation of autophagy is suggested as a therapeutic approach in diverse pathological conditions. Accumulated evidence suggests that intermittent fasting or calorie restriction can lead to the induction of adaptive autophagy and increase longevity of eukaryotic cells. However, prolonged calorie restriction with excessive autophagy response is harmful and can stimulate a type II autophagic cell death. Despite the existence of a close relationship between calorie deprivation and autophagic response in different cell types, the precise molecular mechanisms associated with this phenomenon remain unclear. Here, we aimed to highlight the possible effects of prolonged and short-term calorie restriction on autophagic response and cell homeostasis.

c-kit+ cells offer hopes in ameliorating asthmatic pathologies via regulation of miRNA-133 and miRNA-126.

OBJECTIVES: There are still challenges regarding c-kit+ cells' therapeutic outcome in the clinical setting. Here, we examined the c-kit+ cell effect on the alleviation of asthma by modulating miRNAs expression. MATERIALS AND METHODS: To induce asthma, male rats were exposed to ovalbumin. Bone marrow-derived c-kit+ cells were enriched by MACS. Animals were classified into four groups (6 rats each). Control rats received PBS intratracheally; Ovalbumin-sensitized rats received PBS intratracheally; Ovalbumin-sensitized rats received PBS intratracheally containing 3×105 c-kit+ and c-kit- cells. Cells were stained with Dil fluorescent dye to track in vivo condition. Pathological changes were monitored in asthmatic rats after transplantation of c-kit+ and c-kit- cells. Serum levels of IL-4 and INF-γ were measured by ELISA. Transcription of miRNAs (-126 and 133) was assessed by real-time PCR analysis. RESULTS: Pathological examination and Th1 and Th2 associated cytokine fluctuation confirmed the occurrence of asthma in rats indicated by chronic changes and prominent inflammation compared with the control group (P<0.05). Both c-kit+ and c-kit- cells were verified in pulmonary niche. Administration of c-kit positive cells had the potential to change INF-γ/IL-4 ratio close to the normal values compared with matched-control asthmatic rats (P<0.05). We also found that c-kit+ cells regulated the expression of miRNA-126 and -133, indicated by an increase of miRNA-133 and decrease of miRNA-126 compared with cell-free sensitized groups (P<0.05). CONCLUSION: c-kit- cells were unable to promote any therapeutic outcomes in the asthmatic milieu. c-kit+ cells had the potential to diminish asthma-related pathologies presumably by controlling the transcription of miRNA-126 and -133.

Low-Level Laser Irradiation Modulated Viability of Normal and Tumor Human Lymphocytes In Vitro.

Introduction: Laser radiation is a promising strategy against various malignancies. Recent studies have shown that the application of low-power laser therapy (LPLT) at different doses and exposure times could modulate the growth dynamic of tumor cells. Based on the type of laser, LPLT could potentially trigger cell proliferation, differentiation, and apoptosis in different cell lines. Methods: In this study, MTT assay was used to monitor the effect of low and high laser intensities on the viability of normal and cancer lymphocytes. The protein levels of Ki-67 (a proliferation marker) and Caspase-3 (an apoptosis factor) were measured in human peripheral mononuclear cells (PBMCs) and the B-lymphoblastic cell line (Nalm-6) using flow cytometry after being-exposed to 630-nm LPLT at low (2, 4, 6, and 10 J/cm2 ) and high (15, 30, 60, and 120 J/cm2) energy densities in a continuous mode for 48 and 72 hours. Results: By using higher energy densities, 60 and 120 J/cm2 , a significant decrease was shown in the viability of Nalm-6 cells, which reached 6.6 and 10.1% after 48 hours compared to the control cells (P<0.05). Notably, Cell exposure to doses 30, 60, and 120 J/cm2 yielded 7.5, 12.9, and 21.6 cell viability reduction after 72 hours. The collected data showed that the high-intensity parameters of LPLT (15 to 120 J/cm2) promoted significant apoptotic changes in the exposed cells coincided with the activation of Caspase-3 compared to the none-treated control cells (P<0.05). The data further showed the stimulation of the Ki-67 factor both in primary PBMCs and the lymphoblastic cell line treated with LPLT at energy densities of 4 and 6 J/cm2 (P<0.05), indicating enhanced cell proliferation. Similar to Nalm-6 cells, primary PBMCs showed apoptosis after 48 hours of being exposed to doses 60, and 120 J/cm2 , indicated by increased Caspase-3 levels (P<0.05). As expected, the Nalm-6 cells were resistant to cytotoxic effects of laser irradiation in the first 48 hours (P>0.05) compared to normal PBMCs. The exposure of Nalm-6 cells to low-intensity laser intensities increased a proliferation rate compared to the PBMCs treated with the same doses. Conclusion: We showed the potency of LPLT in the induction of apoptosis and proliferation in human primary PBMCs and Nalm-6 cells in a dose and time-dependent manner after 72 hours.