Hypoxia-inducible factor (HIF)-1 mediates hypoxia- and chronic kidney disease–induced fibrotic events. Here, we assessed whether HIF-1 blockade attenuates the manifestations of diabetic nephropathy in a type 1 diabetic animal model, OVE26. YC-1 [3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole], an HIF-1 inhibitor, reduced whole kidney glomerular hypertrophy, mesangial matrix expansion, extracellular matrix accumulation, and urinary albumin excretion as well as NOX4 protein expression and NADPH-dependent reactive oxygen species production, while blood glucose levels remained unchanged. The role of NOX oxidases in HIF-1–mediated extracellular matrix accumulation was explored in vitro using glomerular mesangial cells. Through a series of genetic silencing and adenoviral overexpression studies, we have defined GLUT1 as a critical downstream target of HIF-1α mediating high glucose–induced matrix expression through the NADPH oxidase isoform, NOX4. Together, our data suggest that pharmacological inhibition of HIF-1 may improve clinical manifestations of diabetic nephropathy.

The small G proteins Rac1 and RhoA regulate actin cytoskeleton, cell shape, adhesion, migration, and proliferation. Recent studies in our laboratory have shown that NADPH oxidase Nox4-derived ROS are involved in transforming growth factor (TGF)-β1-induced rat kidney myofibroblast differentiation assessed by the acquisition of an α-smooth muscle actin (α-SMA) phenotype and expression of an alternatively spliced fibronectin variant (Fn-EIIIA). Rac1 and RhoA are essential in signaling by some Nox homologs, but their role as effectors of Nox4 in kidney myofibroblast differentiation is not known. In the present study, we explored a link among Rac1 and RhoA and Nox4-dependent ROS generation in TGF-β1-induced kidney myofibroblast activation. TGF-β1 stimulated an increase in Nox4 protein expression, NADPH oxidase activity, and abundant α-SMA and Fn-EIIIA expression. RhoA but not Rac1 was involved in TGF-β1 induction of Nox4 signaling of kidney myofibroblast activation. TGF-β1 stimulated active RhoA-GTP and increased Rho kinase (ROCK). Inhibition of RhoA with small interfering RNA and ROCK using Y-27632 significantly reduced TGF-β1-induced stimulation of Nox4 protein, NADPH oxidase activity, and α-SMA and Fn-EIIIA expression. Treatment with diphenyleneiodonium, an inhibitor of NADPH oxidase, did not decrease RhoA activation but inhibited TGF-β1-induced α-SMA and Fn-EIIIA expression, indicating that RhoA is upstream of ROS generation. RhoA/ROCK also regulated polymerase (DNA-directed) δ-interacting protein 2 (Poldip2), a newly discovered Nox4 enhancer protein. Collectively, these data indicate that RhoA/ROCK is upstream of Poldip2-dependent Nox4 regulation and ROS production and induces redox signaling of kidney myofibroblast activation and may broader implications in the pathophysiology of renal fibrosis.

Oral squamous cell carcinoma (OSCC) is a deadly disease that comprises 60% of all head and neck squamous cell cancers. The leaves of the Neem tree (Azadirachta indica) have been used in traditional Ayurvedic medicine for centuries to treat numerous oral maladies and are known to have significant anti-inflammatory properties. We hypothesize that a highly pure super critical CO2 Neem leaf extract (SCNE) prevents initiation and progression of OSCC via downregulation of intra-tumor pro-inflammatory pathways, which promote tumorigenesis. Hence, we investigated the anticancer effects of SCNE using in vitro and in vivo platforms. OSCC cell lines (SCC4, Cal27, and HSC3) were treated with SCNE while inflammation, proliferation, and migration were analyzed over time. SCNE treatment significantly inhibited OSCC cell proliferation and migration and reduced MMP activity in vitro, suggesting its potential to inhibit tumor growth and metastasis. The preventive effects of SCNE in ectopic xenograft and 4NQO-1 (4-Nitroquinoline-1-oxide) carcinogen-induced mouse models of OSCC were also evaluated. Indeed, xenografted nude mice showed significant reduction of OSCC tumor volumes. Likewise, SCNE significantly reduced the incidence of tongue dysplasia in the 4NQO-1 OSCC initiation model. In both OSCC animal models, SCNE significantly depressed circulating pro-cancer inflammatory cytokines (host and tumor-secreted) including NFkB, COX2, IL-1, IL-6, TNFα, and IFNγ. In addition, we demonstrate that SCNE downregulates STAT3 and AKT expression and activity in vitro. We also demonstrate that the primary active component, nimbolide (NIM), has significant anticancer activity in established OSCC xenografts. Lastly, we show that SCNE induces an M1 phenotype in tumor associated macrophages (TAMS) in vivo. Taken together, these data strongly support SCNE as means of preventing OSCC via downregulation of pro-cancer inflammatory cascades and NIM as a potential new therapy for existing OSCC.

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer death in men and women in the United States. Anti-inflammatory blockade has been proven to be a promising avenue of colorectal cancer prevention. However, NSAIDs while effective in curbing CRC risk are too toxic for long-term use in cancer prevention. The Neem tree (Azadirachta indica) is rich in liminoid terpenoids, collectively known as azadiractoids and has been shown to have anti-inflammatory effects. To explore a role of neem in CRC, human colon cancer cell lines HCT116 and HT29 cells were treated with purified Super Critical Neem Extract (SCNE) or the neem liminoid, nimbolide. SCNE treatment resulted in a dose dependent inhibition of CRC cell proliferation and an increase in apoptosis. Treatment with SCNE and nimbolide decreased the expression of transcriptional factors, STAT3 and NF-κB which plays a major role in gene regulation of multiple cellular processes. Protein expression of COX1, IL-6, and TNF-α were decreased on treatment with SCNE in CRC cells. Western blots and Zymogram assays results revealed anti-invasive effect by decreased expression of MMP2 and MMP9 proteins in CRC cells. Overall, these data confirm a potential anti-cancer effect of SCNE, reducing cell proliferation, inflammation, migration, and invasion in human colon cancer cells. Confirming these indications, we found that treatment of mice bearing HT29 and HCT116 xenografted tumors exhibited striking inhibition of colon tumor growth. Clearly we must explore the effect of neem in preclinical animal models for anti-cancer therapy.

BackgroundThe Syrian golden hamster (Mesocricetus aureus) has been used as a model to study infections caused by a number of human pathogens. Studies of immunopathogenesis in hamster infection models are challenging because of the limited availability of reagents needed to define cellular and molecular determinants.ResultsWe sequenced a hamster cDNA library and developed a first-generation custom cDNA microarray that included 5131 unique cDNAs enriched for immune response genes. We used this microarray to interrogate the hamster spleen response to Leishmania donovani, an intracellular protozoan that causes visceral leishmaniasis. The hamster model of visceral leishmaniasis is of particular interest because it recapitulates clinical and immunopathological features of human disease, including cachexia, massive splenomegaly, pancytopenia, immunosuppression, and ultimately death. In the microarray a differentially expressed transcript was identified as having at least a 2-fold change in expression between uninfected and infected groups and a False Discovery Rate of <5%. Following a relatively silent early phase of infection (at 7 and 14 days post-infection only 8 and 24 genes, respectively, were differentially expressed), there was dramatic upregulation of inflammatory and immune-related genes in the spleen (708 differentially expressed genes were evident at 28 days post-infection). The differentially expressed transcripts included genes involved in inflammation, immunity, and immune cell trafficking. Of particular interest there was concomitant upregulation of the IFN-γ and interleukin (IL)-4 signaling pathways, with increased expression of a battery of IFN-γ- and IL-4-responsive genes. The latter included genes characteristic of alternatively activated macrophages.ConclusionsTranscriptional profiling was accomplished in the Syrian golden hamster, for which a fully annotated genome is not available. In the hamster model of visceral leishmaniasis, a robust and functional IFN-γ response did not restrain parasite load and progression of disease. This supports the accumulating evidence that macrophages are ineffectively activated to kill the parasite. The concomitant expression of IL-4/IL-13 and their downstream target genes, some of which were characteristic of alternative macrophage activation, are likely to contribute to this. Further dissection of mechanisms that lead to polarization of macrophages toward a permissive state is needed to fully understand the pathogenesis of visceral leishmaniasis.Electronic supplementary materialThe online version of this article (doi:10.1186/s12865-014-0038-z) contains supplementary material, which is available to authorized users.

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