Potential role of the CD38/cADPR signaling pathway as an underlying mechanism of the effects of medetomidine on insulin and glucose homeostasis

CD38 affects the biological behavior and energy metabolism of nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is the most common malignant tumor type in Southern China and South-East Asia. Cluster of differentiation (CD)38 is highly expressed in the human immune system and participates in the activation of T, natural killer and plasma cells mediated by CD2 and CD3 through synergistic action. CD38 is a type II transmembrane glycoprotein, which was observed to mediate diverse activities, including signal transduction, cell adhesion and cyclic ADP-ribose synthesis. However, the significance of CD38 in NPC biological behavior and cellular energy metabolism has not been examined. In order to elucidate the effect of CD38 on the biological behavior of NPC cells, stable CD38-overexpressed NPC cell lines were established. It was demonstrated that CD38 promoted NPC cell proliferation with Cell Counting Kit-8 and colony formation assays. It was also indicated that CD38 inhibited cell senescence, and promoted cell metastasis. Furthermore, it was determined that CD38 promoted the conversion of cells to the S phase and decreased the content of reactive oxygen species and Ca²⁺. Additionally, cell metabolism assays demonstrated that CD38 increased the concentration of ATP, lactic acid, cyclic adenosine monophosphate and human ADP/acrp30 concentration in NPC cells. To investigate the possible mechanism, bioinformatics analysis and mass spectrometry technology was used to determine the most notably changing molecule and signaling pathways, and it was determined and verified that CD38 regulated the metabolic-associated signaling pathways associated with tumor protein 53, hypoxia inducible factor-1α and sirtuin 1. The present results indicated that CD38 may serve a carcinogenic role in NPC by regulating metabolic-associated signaling pathways.

A radioresistant fraction of acute promyelocytic leukemia cells exhibit CD38 cell-surface antigen and mRNA expression

In the present study, the cell viability and cluster of differentiation (CD)38 mRNA expression were evaluated in radioresistant (Res)-HL60 acute promyelocytic leukemia (APL) cells. Cell viability in Res-HL60 cells was higher compared with wild-type HL60 cells, but did not differ between high and mid/low CD38 antigen expression groups in Res-HL60 cells. A higher expression of CD38 mRNA in Res-HL60 cells was observed, particularly in the CD38^high cell subpopulation. Furthermore, the expression of CD38 mRNA was upregulated following exposure to X-irradiation. In contrast, the characteristic expression of CD45 and CCAAT/enhancer-binding protein α mRNA were not altered. These results suggest that the accumulation of CD38 protein in radioresistant APL cells, resulting from the constant expression of CD38 mRNA induced by X-irradiation, is a characteristic response of the radioresistant-surviving fraction; however, the accumulation of CD38 did not influence the extent of radioresistant behavior.

Effects of pentobarbital, isoflurane, or medetomidine-midazolam-butorphanol anesthesia on bronchoalveolar lavage fluid and blood chemistry in rats

Bronchoalveolar lavage fluid (BALF) is commonly examined for pulmonary toxicity in animal studies. Two common means of anesthesia before euthanasia and bronchoalveolar lavage in rats are intraperitoneal injection of pentobarbital and inhalation of isoflurane. Medetomidine-midazolam-butorphanol is an alternative anesthesia to pentobarbital for animal welfare; however, the effect of this combination on BALF and blood chemistry is unknown. Here, we compared the effects of anesthesia by intraperitoneal injection of pentobarbital or one of two combinations of medetomidine-midazolam-butorphanol (dose, 0.375-2.0-2.5 or 0.15-2.0-2.5 mg/kg) or by inhalation of isoflurane on BALF and blood chemistry in rats with or without pulmonary inflammation. In BALF, we determined total protein, albumin, lactate dehydrogenase, total cell count and neutrophil count. In serum, we conducted a general chemistry screen. After anesthesia with pentobarbital or isoflurane, there were no significant differences between any of the BALF or blood chemistry parameters with or without inflammation. After anesthesia with either of the combinations of medetomidine-midazolam-butorphanol, lactate dehydrogenase, total cell count, neutrophil count, and almost all of the blood chemistry parameters were comparable with those observed after pentobarbital or isoflurane; however, BALF albumin and serum glucose were significantly increased in rats without inflammation. After the combination of low-dose medetomidine in rats with inflammation, BALF parameters were comparable with those observed after pentobarbital or isoflurane. Our results show that, of the anesthetics examined, inhalation of isoflurane is the most appropriate means of anesthesia when examining BALF or serum for toxicity studies in rats.