Mild electrical stimulation with heat shock guides differentiation of embryonic stem cells into Pdx1-expressing cells within the definitive endoderm.

BACKGROUND: Because of the increasing number of diabetic patients, it is important to generate pancreatic and duodenal homeobox gene 1 (Pdx1)-expressing cells, which are capable of differentiating into pancreatic endocrine ß cells. Mild electrical stimulation was reported to modulate the differentiation of ES cells into ectoderm-derived neuronal cells or mesoderm-derived cardiac cells. RESULTS: In this study, we report that mild electrical stimulation with heat shock (MET) potentiates the differentiation of ES cells into definitive endoderm-derived Pdx1-expressing cells. MET has no effect when applied to early definitive endoderm on differentiation day 5. A 1.87-fold increase in the proportion of Pdx1-expressing cells was observed when stimulation was applied to the late definitive endoderm one day prior to the immergence of Pdx1/GFP-expressing cells on differentiation day 7. Pdx1 mRNA was also up-regulated by MET. The potentiating effect of MET synergized with activin and basic fibroblast growth factor into Pdx1-expressing cells. Moreover, MET stimulation on late definitive endoderm up-regulated heat shock protein 72 and activated various kinases including Akt, extracellular signal-regulated kinase, p38, and c-jun NH2-terminal kinase in ES cells. CONCLUSIONS: Our findings indicate that MET induces the differentiation of Pdx1-expressing cells within the definitive endoderm in a time-dependent manner, and suggest useful application for regenerative medicine.

Incidences of Herpes Zoster and Postherpetic Neuralgia in Japanese Adults Aged 50 Years and Older From a Community-based Prospective Cohort Study: The SHEZ Study.

BACKGROUND: Many cross-sectional studies have examined the incidences of herpes zoster (HZ) and postherpetic neuralgia (PHN), but prospective studies in Japanese older adults are lacking. Therefore, we conducted a community-based prospective cohort study to determine the incidence in Japanese adults aged ≥50 years. METHODS: We recruited 12 522 participants from Shozu County, Kagawa Prefecture, between December 2008 and November 2009 and followed participants for 3 years. When a subject presented with symptoms suggestive of HZ, they were examined at collaborating medical institutions and cooperated with onset and recovery surveys (eg, measurement of varicella zoster virus-specific immunity and a pain survey). The hazard ratios (HRs) of HZ and PHN according to sex and age were analyzed by Cox regression analysis with a significance level of 5%. RESULTS: The incidence of HZ was 10.9/1000 person-years (men: 8.5/1000 person-years; women: 12.8/1000 person-years) and was significantly higher in women than in men (HR 1.5; 95% confidence interval, 1.2-1.8). The incidence of PHN was 2.1/1000 person-years (men: 1.7/1000 person-years; women: 2.4/1000 person-years), with no significant sex differences. A total of 19% of HZ cases progressed to PHN; no sex-specific difference in the proportion of PHN cases was observed. CONCLUSIONS: We clarified the accurate incidences of HZ and PHN in a population of Japanese older adults. These incidences increased with age. HZ incidence was higher in women than in men, while PHN incidence did not differ markedly between the sexes.

Insulin receptor activation through its accumulation in lipid rafts by mild electrical stress.

Insulin resistance is due to the reduced cellular response to insulin in peripheral tissues. The interaction of insulin with its receptor is the first step in insulin action and thus the identified target of insulin resistance. It has been well established that defects or mutations in the insulin receptor (IR) cause insulin resistance. Therefore, an IR activator might be a novel therapeutic approach for insulin resistance. Our previous report showed that mild electrical stress (MES) enhanced the insulin-induced signaling pathway. However, the molecular mechanism of the effect of MES remains unclear. We assessed the effect of MES, which is characterized by low-intensity direct current, on insulin signaling in vitro and in vivo. Here, we showed that MES activated the insulin signaling in an insulin-independent manner and improved insulin resistance in peripheral tissues of high fat-fed mice. Moreover, we found that MES increased the localization of IR in lipid rafts and enhanced the level of phosphorylated Akt in insulin-resistant hepatic cells. Ablation of lipid rafts disrupted the effect of MES on Akt activation. Our findings indicate that MES has potential as an activator of IR in an insulin-independent manner, and might be beneficial for insulin resistance in type 2 diabetes.

Glucose uptake in rat skeletal muscle L6 cells is increased by low-intensity electrical current through the activation of the phosphatidylinositol-3-OH kinase (PI-3K) / Akt pathway.

Activation of Akt by insulin is transmitted via phosphatidylinositol-3-OH kinase (PI-3K) and enhances glucose uptake. The PI-3K/Akt signaling is diminished in insulin resistance. Thus, approaches that activate PI-3K/Akt signaling leading to improved glucose uptake may ameliorate hyperglycemia. Here we showed that low-intensity electrical current or mild electrical stimulation (MES) activated the PI-3K/Akt signaling and increased the glucose uptake in rat skeletal muscle (L6) cells. The glucose uptake enhanced by MES in muscle cells, the major cells involved in glucose disposal, suggests MES may have a possible beneficial effect on hyperglycemia.

Modified mild heat shock modality attenuates hepatic ischemia/reperfusion injury.

BACKGROUND: Hepatic ischemia/reperfusion (I/R) injury is a pathologic process caused by hepatic surgery and transplantation, and still remains a severe clinical problem. It was shown that preconditioning by hyperthermia might protect tissues against I/R injury. But hyperthermia could be laborious and time-consuming. Alternatively, the application of mild electrical stimulation (MES) has been reported to have positive effects in clinical settings on several medical ailments. Thus, we modified the preconditioning approach by combining short-term mild heat shock (HS) and MES, and evaluated the effect of HS+MES pretreatment on hepatic injury induced by I/R. MATERIALS AND METHODS: C57BL/6J mice were sham treated or treated three times with HS (42 degrees C) and/or MES (12V) for 20min, carried out every other d within 1 wk. After the last treatment, mice were subjected to hepatic ischemia for 30 or 60min and reperfusion for 6h. Liver injury was assessed by evaluating the levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). The expressions of pro-inflammatory cytokines and heat shock protein (Hsp) 72 in liver tissues were also assessed by real-time PCR and Western blotting analyses, respectively. RESULTS: HS+MES pretreatment suppressed the hepatic I/R-induced release of serum AST and ALT and the mRNA levels of some pro-inflammatory cytokines. In addition, HS+MES up-regulated the expression of Hsp72 in mice liver. CONCLUSIONS: HS+MES preconditioning ameliorated hepatic I/R injury possibly through Hsp72 induction, and suppressed pro-inflammatory cytokine expression in mice liver.

IFN-gamma down-regulates Hsp27 and enhances hyperthermia-induced tumor cell death in vitro and tumor suppression in vivo.

Hyperthermia is used as one of the treatment modalities for various types of cancer, but the acquisition of thermotolerance in cancer cells, through the induction of heat shock proteins (Hsps), renders hyperthermia less effective. Among the Hsp family members, Hsp27 is frequently associated with thermotolerance and chemoresistance. Thus, down-regulation of Hsp27 expression during hyperthermic or chemotherapeutic applications is a promising approach to efficient tumor treatment. In the present study, we found that the cytokine interferon-gamma (IFN-gamma) suppresses the basal, the heat shock-induced and the cisplatin-induced expression of Hsp27 in HSC-2 (oral squamous carcinoma) and A549 (lung cancer) cells but not in 16HBE14o- (normal bronchial epithelial cells). Neither IFN-alpha nor IFN-beta affected Hsp27 expression, suggesting the specificity of IFN-gamma. We also demonstrate here that IFN-gamma suppresses Hsp27 basal transcription and promoter activity, and this is mediated specifically through one of the two Sp1 sites in the proximal region of the Hsp27 promoter. More importantly, pre-treatment of cells with IFN-gamma enhanced the induction of cell death by hyperthermia and cisplatin treatments in the tumor cell lines, HSC-2 and A549, but has no effect in 16HBE14o-, indicating a tumor cell-specific effect of IFN-gamma. Furthermore, the combination treatment of hyperthermia and IFN-gamma suppressed tumor growth in vivo more effectively than hyperthermia treatment alone. Together, our findings propose that IFN-gamma could be a useful potentiator of hyperthermia and cisplatin in cancer therapy.

VZV skin-test reaction, but not antibody, is an important predictive factor for postherpetic neuralgia.

BACKGROUND: The decline of cell-mediated immunity (CMI) is thought to be related to the risk of postherpetic neuralgia (PHN) as well as herpes zoster (HZ). However, the relationship between immunological condition and the incidence of PHN is still unclear. OBJECTIVE: We conducted a large-scale prospective cohort study to clarify the relationship between immunological factors for varicella-zoster virus (VZV) and the incidence of PHN. METHODS: We carried out a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a follow-up period of 3 years, with a focus on the relationship between cell-mediated and humoral immunity and the incidence of PHN. A total of 12,522 people over the age of 50 were enrolled in this study, and 401 registrants were diagnosed with HZ, including 79 PHN cases. We evaluated anatomical location and severity of skin lesion, acute pain severity, presence or absence of abnormal sensations, CMI assessed by VZV skin test, and VZV-specific antibody titer measured by serological tests. RESULTS: The incidence of PHN was significantly associated with a weak response to the VZV skin test, as well as facial or lumbosacral localization of skin rash, severe skin lesion, severe acute pain, and presence of abnormal sensations, but not related to VZV-specific antibody titer. CONCLUSION: The incidence of PHN is significantly associated with the decline of VZV-specific CMI, but not related to VZV-specific humoral immunity.

Mild electrical stimulation increases stress resistance and suppresses fat accumulation via activation of LKB1-AMPK signaling pathway in C. elegans.

Electrical current at physiological strength has been applied as a therapeutic approach for various diseases. Several of our works showed that mild electrical stimulation (MES) at 0.1-ms pulse width has positive impact on organisms. But despite the growing evidence of the beneficial effects of MES, its effects on individual animals and the molecular underpinnings are poorly understood and rarely studied. Here, we examined the effects of MES on individual animal and its mechanisms by mainly using Caenorhabditis elegans, a powerful genetic model organism. Interestingly, MES increased stress resistance and suppressed excess fat accumulation in wild-type N2 worms but not in AMPK/AAK-2 and LKB1/PAR-4 mutant worms. MES promoted the nuclear localization of transcription factors DAF-16 and SKN-1 and consequently increased the expression of anti-stress genes, whereas MES inhibited the nuclear localization of SBP-1 and suppressed the expression of lipogenic genes. Moreover, we found that MES induced the activation of LKB1/PAR4-AMPK/AAK2 pathway in C. elegans and in several mammalian cell lines. The mitochondrial membrane potential and cellular ATP level were slightly and transiently decreased by MES leading to the activation of LKB1-AMPK signaling pathway. Together, we firstly and genetically demonstrated that MES exerts beneficial effects such as stress resistance and suppression of excess fat accumulation, via activation of LKB1-AMPK signaling pathway.

An inverse correlation of VZV skin-test reaction, but not antibody, with severity of herpes zoster skin symptoms and zoster-associated pain.

BACKGROUND: Cell-mediated immunity (CMI) has been considered to be related to the development of herpes zoster (HZ). However, there have been no large-scale prospective studies on the relationship between VZV-specific CMI and severity of HZ. OBJECTIVE: We carried out a large-scale prospective cohort study to clarify the relationship between immunological factors for varicella-zoster virus (VZV) and the clinical severity of HZ. METHODS: We carried out a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a median follow-up period of 2 years, with a focus on the relationship between cell-mediated and humoral immunity and the severity of skin lesions and zoster-associated pain. A total of 12,522 people over the age of 50 were enrolled in this study, and 258 registrants were diagnosed as HZ. CMI was measured by VZV skin test, and humoral immunity was assessed with serological tests (neutralization test, immunoadherence hemagglutination test, and gpELISA test) for VZV-specific antibodies. RESULTS: CMI to VZV assessed by VZV skin test showed a significant inverse relationship to the severity of HZ skin lesions, and also to the severity of acute and subacute pain. Furthermore, weak response to the VZV skin test was associated with a high risk of post-herpetic neuralgia. In contrast, VZV-specific antibody titer was not associated with the severity of skin lesions and zoster-associated pain. CONCLUSION: VZV-specific CMI, but not humoral immunity, may play a key role in controlling the severity of HZ skin lesions and zoster-associated pain.

Diethyldithiocarbamate induces apoptosis in HHV-8-infected primary effusion lymphoma cells via inhibition of the NF-κB pathway.

Primary effusion lymphoma (PEL) is a subtype of B-cell lymphoma caused by human herpes virus 8/Kaposi sarcoma-associated herpes virus (HHV-8/KSHV), which is mostly found in patients with AIDS and has poor prognosis. Nuclear factor (NF)-κB pathway is constitutively activated in HHV-8-infected PEL cells and plays a crucial role in tumorigenesis. Recently, it has been shown that diethyldithiocarbamate (DDTC), an active metabolite of disulfiram, has apoptotic activity in cancer cells. Here, we investigated the effect of DDTC on PEL using a PEL mouse model generated by intraperitoneal injection of BC-3 cells, a PEL cell line. DDTC ameliorated the symptoms of PEL in these mice, such as development of ascites, splenomegaly and increase of body weight, in comparison with PBS-treated controls. Moreover, we determined in vitro that DDTC suppressed the constitutively activated NF-κB pathway in BC-3 cells. Methylthiotetrazole assay revealed that the cell proliferation of various PEL cell lines was significantly suppressed by the treatment of DDTC. DDTC also induced the expression of cleaved caspase-3, an apoptosis marker, whereas the addition of Q-VD-OPh, a pan-caspase inhibitor, inhibited cell apoptosis induced by DDTC treatment. Together, our results indicated that DDTC induces apoptosis via inhibition of the NF-κB signaling pathway in HHV-8-infected PEL cells. This study suggests the potential use of DDTC as a therapeutic approach for PEL.

Mild electrical stimulation increases ubiquitinated proteins and Hsp72 in A549 cells via attenuation of proteasomal degradation.

To explore the cellular effects of mild electrical stimulation (MES), we treated A549 cells with low-intensity direct current at 5 V applied for 10 min. MES did not induce cell cytotoxicity or the unfolded protein response (UPR). Interestingly, the expression of ubiquitinated proteins and heat shock protein (Hsp) 72 was increased but not that of other Hsps. MES attenuated the degradation of Hsp72, which is a substrate of the proteasome-ubiquitin system. These results, along with the observed increase in expression of ubiquitinated proteins, imply that MES may affect the proteasome system, which regulates the fate of many proteins.