1.PD-L1 Expression on Circulating CD34+ Hematopoietic Stem Cells Closely Correlated with T-cell Apoptosis in Chronic Hepatitis C Infected Patients
Hussein ABDELLATIF ; Gamal SHIHA
International Journal of Stem Cells 2018;11(1):78-86
BACKGROUND AND OBJECTIVES: Lack of understanding of the interplay between hematopoietic stem cells (HSCs) and the immune system has severely hampered stem cell research. Programmed death-1 (PD-L1) has been reported on parenchymal cells in patients with chronically inflamed livers and found to play an essential role in T cell homeostasis regulation. However, the bidirectional interaction between HSCs and lymphocytes remains elusive. Here, we aimed to get more insight into circulating CD34+ HSCs PD-L1 expression and T cell apoptosis in chronic HCV infected patients. METHODS: CD34+ HSCs were isolated and purified by immunomagnetic separation. PD-L1 expression was analyzed by quantitative PCR and flow cytometry. Furthermore, co-culture experiments between CD34+ HSCs and T-lymphocytes were established. T-cell lymphocyte apoptosis in peripheral blood and in cultures was detected. RESULTS: CD34+ HSCs constitutively express low levels of PD-L1. Its expression is up-regulated in chronic HCV infected patients. Moreover, PD-L1 expression on circulating CD34+ HSCs enhanced T cell apoptosis in peripheral blood and co-culture. CONCLUSION: Our results suggest novel bidirectional interplay between HSCs and lymphocytes mediated by PD-L1 expression on CD34+ HSCs. PD-L1 expression correlated with T-cell lymphocyte apoptosis. This may contribute to immunomodulatory properties of HSCs which improves its use for allogeneic transplantation.
Apoptosis
;
Coculture Techniques
;
Flow Cytometry
;
Hematopoietic Stem Cells
;
Hepatitis C, Chronic
;
Hepatitis, Chronic
;
Homeostasis
;
Humans
;
Immune System
;
Immunomagnetic Separation
;
Liver
;
Lymphocytes
;
Polymerase Chain Reaction
;
Stem Cell Research
;
T-Lymphocytes
;
Transplantation, Homologous
2.Effect of Intermittent Fasting on Glucose Homeostasis and Bone Remodeling in Glucocorticoid-Induced Osteoporosis Rat Model
Majed G. ALROWAILI ; Abdelaziz M. HUSSEIN ; Elsayed A. EID ; Mohamed S. SERRIA ; Hussein ABDELLATIF ; Hussein F SAKR
Journal of Bone Metabolism 2021;28(4):307-316
Background:
The present study examined the effect of intermittent fasting (IF) on bone mineral content (BMC) and bone mineral density (BMD) and the markers of bone remodeling in a glucocorticoid-induced osteoporosis (GIO) rat model.
Methods:
Forty male rats were allocated to 4 groups (N=10 per group): control group of normal rats; control+IF group (normal rats subjected to IF for 16-18 hr daily for 90 days); dexamethasone (DEX) group: (DEX [0.5 mg i.p.] for 90 days); and DEX+IF group (DEX and IF for 90 days). By the end of the experiment, BMD and BMC in the right tibia were measured. Serum levels of the following were measured: glucose; insulin; triglycerides (TGs); total cholesterol; parathyroid hormone (PTH); osteoprotegerin (OPG); receptor activator of nuclear factor-κB (RANK); bone-resorbing cytokines, including bone deoxypyridinoline (DPD), N-terminal telopeptide of collagen type I (NTX-1), and tartrate-resistant acid phosphatase 5b (TRAP-5b); and bone-forming cytokines, including alkaline phosphatase (ALP) and osteocalcin (OC).
Results:
DEX administration for 90 days resulted in significantly increased serum levels of glucose, insulin, TGs, cholesterol, PTH, OPG, DPD, NTX-1, and TRAP-5b and significantly decreased BMD, BMC, and serum levels of RANK, OC, and ALP (all P<0.05). IF for 90 days significantly improved all these parameters (all P<0.05).
Conclusions
IF corrected GIO in rats by inhibiting osteoclastogenesis and PTH secretion and stimulating osteoblast activity.