Tumor necrosis factor-α modifies the effects of Shiga toxin on glial cells

Ginger facilitates cell migration and heat tolerance in mouse fibroblast cells

The components of ginger root (Zingiber officinale Roscoe) are widely used for various medicinal purposes. Several bioactive compounds have been identified in ginger, including 6‑, 8‑ and 10‑gingerols, and 6‑shogaol, which are agonists of the thermo‑sensors transient receptor potential (TRP) cation channel subfamily V member 1 and TRP ankyrin 1. Our previous study demonstrated that ginger powder may affect human metabolism in vivo. However, the effects of the bioactive compounds of ginger on cells have not been completely elucidated. The present study investigated whether ginger powder extracts could modify cell functions in mouse fibroblast cells. The active components of ginger powder extracts were characterized using high‑performance liquid chromatography. The activation of protein kinases, actin assembly, cell migration, expression levels of heat shock proteins (HSPs) and cell viability after heat shock were analyzed in NIH3T3 mouse fibroblast cells. Subsequently, 6‑, 8‑, 10‑ and 12‑gingerols, as well as 6‑, 8‑ and 10‑shogaols, were detected in ginger powder extracts. The levels of phosphorylated Akt, mTOR, ERK and p38 MAPK increased after a 10‑min stimulation with ginger powder extracts. In addition, HSP expression levels, lamellipodia formation occurring at cell edges, cell migration and tolerance against heat shock were facilitated following ginger powder extract stimulation. These results suggest that ginger modified cell functions, including actin assembly and heat tolerance, in vitro.

Pathogenic functions and diagnostic utility of cytokines/chemokines in EHEC-HUS

Hemolytic - uremic syndrome (HUS) is a severe complication of infection by Shiga toxin (STx)-producing enterohemorrhagic Escherichia coli. Hemolytic - uremic syndrome is defined clinically as a triad of non-immune microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injuries. Neurologic complications such as acute encephalopathy are also observed. In humans, endothelial cells, proximal tubular epithelial cells, mesangial cells, podocytes, intestinal epithelial cells, and monocytes / macrophages are susceptible to STx-mediated injury. Shiga toxin induces the secretion of inflammatory cytokines and chemokines from susceptible cells, including tumor necrosis factor-α interleukin (IL)-1, IL-6, and IL-8. These cytokines and chemokines contribute to the pathogenesis of HUS and encephalopathy by enhancing STx-induced cytotoxicity and inducing inflammatory cell infiltration. Serum cytokine/chemokine levels are therefore useful as indicators of disease activity and predictors of progression from acute kidney injury to chronic kidney disease. Anti-inflammation therapy combined with apheresis to remove excessive cytokines / chemokines and methylprednisolone pulse therapy to suppress cytokine/chemokine production may be an effective treatment regimen for severe E. coli-associated HUS. However, this regimen requires careful monitoring of potential side effects, such as infections, thrombus formation, and hypertension.

Corticosterone inhibits the expression of cannabinoid receptor-1 and cannabinoid receptor agonist-induced decrease in cell viability in glioblastoma cells

The endocannabinoid system regulates physiological and pathological conditions, including inflammation and cancer. Recently, emotional and physical stressors were observed to be involved in impairing the endocannabinoid system, which was concomitant with an increase in serum corticosteroids. However, the influence of corticosteroids on the endocannabinoid system has yet to be completely elucidated. The present study investigated the effects of corticosterone, one of the corticosteroids, on the endocannabinoid system in malignant glioblastoma cells in vitro. U-87 MG cells derived from malignant glioblastoma were subjected to corticosterone stimulation and their viability, signal transduction, and endocannabinoid-related gene expression were examined. Corticosterone decreased the mRNA and protein expressions of cyclooxygenase-2. Of note, although endocannabinoids decreased cell viability, corticosterone inhibited the cannabinoid receptor agonist-induced decrease in cell viability by downregulating the mRNA and protein expressions of cannabinoid receptor 1 (CB1) in glioblastoma cells. These results suggest that corticosteroids modify the endocannabinoid system in glioblastoma cells, and a reduction in the beneficial anti-tumor effects of endocannabinoids through downregulation of the CB1 receptor by corticosterone may promote the malignant phenotype of glioblastoma.

Capsaicin partially mimics heat in mouse fibroblast cells in vitro

Capsaicin activates transient receptor potential vanilloid 1 (TRPV1), a cation channel in the transient receptor potential family, resulting in the transient entry of Ca²⁺ and Mg²⁺ and a warm sensation. However, the effects of capsaicin on cells have not fully elucidated in fibroblasts. In this study, we investigated whether capsaicin could induce signal transduction in mouse fibroblast cells and compared the effect with that of heat-induced signal transduction. The activation of the mitogen-activated protein kinases (MAPKs) ERK and p38 MAPK, expression levels of heat shock protein 70 (HSP70) and HSP90, actin assembly, and cell proliferation were analyzed in NIH3T3 mouse fibroblast cells. A 15-min stimulation with capsaicin (∼100 μM) phosphorylated ERK and p38 MAPK and induced actin assembly. A 2-day stimulation with capsaicin increased the level of HSP70, but not HSP90, and the 2-day stimulation with capsaicin (∼100 μM) did not affect cell proliferation. A 15-min exposure to moderate heat (39.5 °C) phosphorylated both ERK and p38 MAPK and induced actin assembly to similar degrees as stimulation with capsaicin. A 2-day exposure to moderate heat increased the levels of both HSP70 and HSP90 and prevented cell proliferation. However, the 2-day stimulation with capsaicin (100 μM) failed to prevent heat shock-induced cell death. Thus, our results suggest that the effects of capsaicin on fibroblast cells partially differ from those of heat. Notably, the 2-day stimulation with capsaicin was not sufficient to develop heat tolerance in fibroblast cells.