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Objective Heat shock factor 1 (HSF1), a transcriptional regulator of heat shock proteins (HSPs), is an attractive therapeutic target for cancer. However, only a few HSF1 inhibitors have been identified so far.Methods The mRNA and protein levels of HSF1, HSPs, cleaved PARP, and phosphorylated HSF1 were examined by real-time PCR and Western blot. Forced expression, RNA interference, and immunofluorescence assay were used for mechanistic studies. Cell viability and apoptosis were measured by WST-8 assay and flow cytometry, respectively. Xenograft studies were performed in nude mice to evaluate the effect of dorsomorphin and an HSP90 inhibitor on tumor growth.Results Dorsomorphin suppressed multiple stimuli-induced and constitutive HSPs expression in cancer cells. Mechanistic studies revealed that dorsomorphin reduced heat-induced HSP expression independent of adenosine monophosphate activated protein kinase. Dorsomorphin reduced heat-stimulated HSF1 Ser320 phosphorylation and nuclear translocation, as well as resting nuclear HSF1 levels in cancer cells. Dorsomorphin induced cancer cell apoptosis by inhibiting HSF1 expression. A structure-activity study revealed that the 4-pyridyl at the 3-site of the pyrazolo [1, 5-a]pyrimidine ring is critical for the anti-HSF1 activities of dorsomorphin. Dorsomorphin sensitized cancer cells to HSP90 and proteasome inhibitors and inhibited HSP70 expression induced by these inhibitors in vitro. In tumor-bearing nude mice, dorsomorphin enhanced HSP90 inhibitor-induced cancer cell apoptosis, tumor growth inhibition, and HSP70 expression.Conclusions Dorsomorphin is an HSF1 inhibitor. It induces cancer cell apoptosis, sensitizes cancer cells to both HSP90 and proteasome inhibitors, and suppresses HSP upregulation by these drugs, which may prevent the development of drug resistance. Hence, dorsomorphin and its derivates may serve as potential precursors for developing drugs against cancer.

Obesity and related inflammation are critical for the pathogenesis of insulin resistance, but the underlying mechanisms are not fully understood. Formyl peptide receptor 2 (FPR2) plays important roles in host immune responses and inflammation-related diseases. We found that Fpr2 expression was elevated in the white adipose tissue of high-fat diet (HFD)–induced obese mice and db/db mice. The systemic deletion of Fpr2 alleviated HFD-induced obesity, insulin resistance, hyperglycemia, hyperlipidemia, and hepatic steatosis. Furthermore, Fpr2 deletion in HFD-fed mice elevated body temperature, reduced fat mass, and inhibited inflammation by reducing macrophage infiltration and M1 polarization in metabolic tissues. Bone marrow transplantations between wild-type and Fpr2−/− mice and myeloid-specific Fpr2 deletion demonstrated that Fpr2-expressing myeloid cells exacerbated HFD-induced obesity, insulin resistance, glucose/lipid metabolic disturbances, and inflammation. Mechanistic studies revealed that Fpr2 deletion in HFD-fed mice enhanced energy expenditure probably through increasing thermogenesis in skeletal muscle; serum amyloid A3 and other factors secreted by adipocytes induced macrophage chemotaxis via Fpr2; and Fpr2 deletion suppressed macrophage chemotaxis and lipopolysaccharide-, palmitate-, and interferon-γ–induced macrophage M1 polarization through blocking their signals. Altogether, our studies demonstrate that myeloid Fpr2 plays critical roles in obesity and related metabolic disorders via regulating muscle energy expenditure, macrophage chemotaxis, and M1 polarization.

Impairment of the immune system is a developing concern in evaluating the toxicity of cadmium (Cd). In the present study, we investigated if Cd could impair cutaneous wound healing through interfering with inflammation after injury. We found that exposure of mice to CdCl2 through drinking water at doses of 10, 30, and 50 mg/l for 8 weeks significantly impaired cutaneous wound healing. Chronic 30 mg/l CdCl2 treatment elevated murine blood Cd level comparable to that of low dose Cd-exposed humans, had no effect on blood total and differential leukocyte counts, but reduced neutrophil infiltration, chemokines (CXCL1 and CXCL2), and proinflammatory cytokines (TNFα, IL-1β, and IL-6) expression in wounded tissue at early stage after injury. Wounded tissue homogenates from CdCl2-treated mice had lower chemotactic activity for neutrophils than those from untreated mice. Mechanistic studies showed that chronic Cd treatment suppressed ERK1/2 and NF-κB p65 phosphorylation in wounded tissue at early stage after injury. Compared with neutrophils isolated from untreated mice, neutrophils from CdCl2 treated mice and normal neutrophils treated with CdCl2 invitro both had lower chemotactic response, calcium mobilization and ERK1/2 phosphorylation upon chemoattractant stimulation. Collectively, our study indicate that chronic low-dose Cd exposure impaired cutaneous wound healing by reducing neutrophil infiltration through inhibiting chemokine expression and neutrophil chemotactic response, and suppressing proinflammatory cytokine expression. Cd may suppress chemokine and proinflammatory expression through inactivating ERK1/2 and NF-κB, and inhibit neutrophil chemotaxis by attenuating calcium mobilization and ERK1/2 phosphorylation in response to chemoattractants.

AIMS: Lower androgen level in elderly men is a risk factor of Alzheimer's disease (AD). It has been reported that androgen reduces amyloid peptides (Aβ) production and increases Aβ degradation by neurons. Activated microglia are involved in AD by either clearing Aβ deposits through uptake of Aβ or releasing cytotoxic substances and pro‐inflammatory cytokines. Here, we investigated the effect of androgen on Aβ uptake and clearance and Aβ‐induced inflammatory response in microglia, on neuronal death induced by Aβ‐activated microglia, and explored underlying mechanisms. METHODS: Intracellular and extracellular Aβ were examined by immunofluorescence staining and Western blot. Amyloid peptides (Aβ) receptors, Aβ degrading enzymes, and pro‐inflammatory cytokines were detected by RT‐PCR, real‐time PCR, and ELISA. Phosphorylation of MAP kinases and NF‐κB was examined by Western blot. RESULTS: We found that physiological concentrations of androgen enhanced Aβ(42) uptake and clearance, suppressed Aβ(42)‐induced IL‐1β and TNFα expression by murine microglia cell line N9 and primary microglia, and alleviated neuronal death induced by Aβ(42)‐activated microglia. Androgen administration also reduced Aβ(42)‐induced IL‐1β expression and neuronal death in murine hippocampus. Mechanistic studies revealed that androgen promoted microglia to phagocytose and degrade Aβ(42) through upregulating formyl peptide receptor 2 and endothelin‐converting enzyme 1c expression, and inhibited Aβ(42)‐induced pro‐inflammatory cytokines expression via suppressing MAPK p38 and NF‐κB activation by Aβ(42), in an androgen receptor independent manner. CONCLUSION: Our study demonstrates that androgen promotes microglia to phagocytose and clear Aβ(42) and inhibits Aβ(42)‐induced inflammatory response, which may play an important role in reducing the neurotoxicity of Aβ.

FAM3B, also named PANDER, is a cytokine-like protein identified in 2002. Previous studies showed that FAM3B regulates glucose and lipid metabolism through interaction with liver and endocrine pancreas. FAM3B is also expressed by other tissues but its basic function is unclear. In this study, we found that FAM3B was expressed in mouse colon, intestine, liver and lung tissues and multiple types of cell lines, including murine pancreatic β-cell (Min6), microglia (N9) and muscle cell (C2C12); human colon cancer cells (HCT8, HCT116, HT29), hepatocyte (HL-7702), hepatocellular carcinoma cell (SMMC-7721) and lung carcinoma cell (A549). Inhibition of FAM3B expression by RNA interference induced apoptotic cell death of HCT8, HCT116, A549, N9, C2C12 and Min6 cells and decreased cell viability of HL-7702 and murine primary hepatocytes. Further studies with HCT8 cells showed that knockdown of FAM3B increased the protein levels of membrane-bound Fas and Bax, reduced the expression of Bcl-2, promoted the cleavage of caspases-8, -3, -9 and PARP, and the nuclear translocation of cleaved PARP. These results suggest that FAM3B silencing activates both extrinsic and intrinsic apoptotic pathways. Mechanistic studies showed that neutralizing antibody against Fas or silencing Fas-associated death domain had no effect on, while caspase inhibitors could significantly reverse FAM3B knockdown induced apoptosis, suggesting Fas and death receptor mediated extrinsic apoptotic pathway is not involved in FAM3B silencing induced apoptosis. Further studies showed that p53 was significantly upregulated after FAM3B knockdown. Silencing p53 could almost completely reverse FAM3B knockdown induced upregulation of Bax, downregulation of Bcl-2, cleavage of caspases-8, -9, -3, and apoptotic cell death, suggesting p53-dependent pathway plays critical roles in FAM3B silencing induced apoptosis. Studies with HCT116 cells confirmed that inhibition of FAM3B expression induced apoptosis through p53-dependent pathway. Furthermore, knockdown of FAM3B reduced the protein level of Mdm2 and promoted p53 phosphorylation. Taken together, our studies demonstrated that silencing FAM3B promoted p53 phosphorylation and induced p53 accumulation by decreasing Mdm2 expression, which resulted in apoptotic cell death.

MicroRNAs (miRNAs) are a new class of regulatory molecules implicated in type 2 diabetes, which is characterized by insulin resistance and hepatic glucose overproduction. We show that miRNA-451 (miR-451) is elevated in the liver tissues of dietary and genetic mouse models of diabetes. Through an adenovirus-mediated gain- and loss-of-function study, we found that miR-451 negatively regulates hepatic gluconeogenesis and blood glucose levels in normal mice and identified glycerol kinase (Gyk) as a direct target of miR-451. We demonstrate that miR-451 and Gyk regulate hepatic glucose production, the glycerol gluconeogenesis axis, and the AKT-FOXO1-PEPCK/G6Pase pathway in an opposite manner; Gyk could reverse the effect of miR-451 on hepatic gluconeogenesis and AKT-FOXO1-PEPCK/G6Pase pathway. Moreover, overexpression of miR-451 or knockdown of Gyk in diabetic mice significantly inhibited hepatic gluconeogenesis, alleviated hyperglycemia, and improved glucose tolerance. Further studies showed that miR-451 is upregulated by glucose and insulin in hepatocytes; the elevation of hepatic miR-451 in diabetic mice may contribute to inhibiting Gyk expression. This study provides the first evidence that miR-451 and Gyk regulate the AKT-FOXO1-PEPCK/G6Pase pathway and play critical roles in hepatic gluconeogenesis and glucose homeostasis and identifies miR-451 and Gyk as potential therapeutic targets against hyperglycemia in diabetes.