Sulfamethizole attenuates poloxamer 407-induced atherosclerotic neointima formation via inhibition of mTOR in C57BL/6 mice

Mammalian target of Rapamycin C1 (mTORC1) inhibition limits plaque progression in atherosclerosis. The present study evaluated the protective effect of sulfamethizole on poloxamer 407-induced atherosclerotic neointima formation in C57BL/6 mice via mTOR inhibition. Poloxamer 407 (P-407) (0.5 g/kg body weight) was administered intraperitoneally to male C57BL/6 mice every third day for 148 days to induce chronic hyperlipidemia. From Day 121 to 148, animals were additionally administered Sulfamethizole (5, 10, and 50 mg/kg, p.o.), Rapamycin (0.5 mg/kg, positive control), or vehicle (1 ml/kg). Plasma lipid levels were measured on Days 120 and 148. Upon sacrifice, histological studies were performed, and aortic tissue interleukin (IL)-6, tumor necrosis factor-α (TNF-α), and mTOR levels were evaluated. A molecular docking study was carried out to mimic the interaction of sulfamethizole with mTOR protein. Chronic P-407 administration significantly (p < 0.001) elevated plasma lipid levels, compared with those of the normal control group. Chronic hyperlipidemia resulted in increased tunica intima thickness, collagen deposition, and IL-6, TNF-α, and mTOR levels. Treatment with Sulfamethizole attenuated these parameters significantly in a dose-dependent manner. Molecular docking studies showed a significant interaction of Sulfamethizole with mTOR. In conclusion, this study suggests that sulfamethizole significantly limits poloxamer 407-induced atherosclerotic neointima formation in C57BL/6 mice via mTOR inhibition.     

Loss of DNA repair mechanisms in cardiac myocytes induce dilated cardiomyopathy

Cardiomyopathy is a progressive disease of the myocardium leading to impaired contractility. Genotoxic cancer therapies are known to be potent drivers of cardiomyopathy, whereas causes of spontaneous disease remain unclear. To test the hypothesis that endogenous genotoxic stress contributes to cardiomyopathy, we deleted the DNA repair gene Ercc1 specifically in striated muscle using a floxed allele of Ercc1 and mice expressing Cre under control of the muscle-specific creatinine kinase (Ckmm) promoter or depleted systemically (Ercc1^−/D mice). Ckmm-Cre^+/−;Ercc1^−/fl mice expired suddenly of heart disease by 7 months of age. As young adults, the hearts of Ckmm-Cre^+/−;Ercc1^−/fl mice were structurally and functionally normal, but by 6-months-of-age, there was significant ventricular dilation, wall thinning, interstitial fibrosis, and systolic dysfunction indicative of dilated cardiomyopathy. Cardiac tissue from the tissue-specific or systemic model showed increased apoptosis and cardiac myocytes from Ckmm-Cre^+/-;Ercc1^−/fl mice were hypersensitive to genotoxins, resulting in apoptosis. p53 levels and target gene expression, including several antioxidants, were increased in cardiac tissue from Ckmm-Cre^+/−;Ercc1^−/fl and Ercc1^−/D mice. Despite this, cardiac tissue from older mutant mice showed evidence of increased oxidative stress. Genetic or pharmacologic inhibition of p53 attenuated apoptosis and improved disease markers. Similarly, overexpression of mitochondrial-targeted catalase improved disease markers. Together, these data support the conclusion that DNA damage produced endogenously can drive cardiac disease and does so mechanistically via chronic activation of p53 and increased oxidative stress, driving cardiac myocyte apoptosis, dilated cardiomyopathy, and sudden death.     

Inhibition of susceptible water soaking and/or hypersensitive reaction in cotton by exopolysaccharide of avirulentXanthomonas campestris pv.malvacearum

The exopolysaccharide (EPS) of avirulentXanthomonas campestris pv.Malvacearum race-32 did not contain the watersoaking (WS)— inducing factor but contained necrotic reaction (NR)-inducing factor and induced NR on resistant cotton (cv. 101-102B) on which the viable cells of the same avirulent race-32 produced hypersensitive reaction (HR). NR and HR were differentiated on the basis of the induction period required, visible reaction on infiltrated areas, bacterial constituents or metabolite responsible, involvement of host constituent during these reactions and its chemical inhibition. Pre and/or challenge inoculation of EPS of avirulent race-32 (3 mg per infiltration or lesion) in susceptible or resistant cotton cultivars, on pre-and/or post-infiltrated (0–8 h) exponential-phase culture of virulent race-32 inhibited the WS and/or HR of the virulent race in susceptible or resistant cotton.     

Elasto-regenerative properties of polyphenols

Abdominal aortic aneurysms (AAA) are progressive dilatations of infra-renal aorta causing structural weakening rendering the aorta prone to rupture. AAA can be potentially stabilized by inhibiting inflammatory enzymes such as matrix metalloproteinases (MMP); however, active regression of AAA is not possible without new elastic fiber regeneration. Here we report the elastogenic benefit of direct delivery of polyphenols such as pentagalloyl glucose (PGG), epigallocatechin gallate (EGCG), and catechin, to smooth muscle cells obtained either from healthy or from aneurysmal rat aorta. Addition of 10 μg/ml PGG and ECGC induce elastin synthesis, organization, and crosslinking while catechin does not. Our results indicate that polyphenols bind to monomeric tropoelastin and enhance coacervation, aid in crosslinking of elastin by increasing lysyl oxidase (LOX) synthesis, and by blocking MMP-2 activity. Thus, polyphenol treatments leads to increased mature elastin fibers synthesis without increasing the production of intracellular tropoelastin.     

Phenotypic profiling of mGlu7 knockout mice reveals new implications for neurodevelopmental disorders

Neurodevelopmental disorders are characterized by deficits in communication, cognition, attention, social behavior and/or motor control. Previous studies have pointed to the involvement of genes that regulate synaptic structure and function in the pathogenesis of these disorders. One such gene, GRM7, encodes the metabotropic glutamate receptor 7 (mGlu₇), a G protein‐coupled receptor that regulates presynaptic neurotransmitter release. Mutations and polymorphisms in GRM7 have been associated with neurodevelopmental disorders in clinical populations; however, limited preclinical studies have evaluated mGlu₇ in the context of this specific disease class. Here, we show that the absence of mGlu₇ in mice is sufficient to alter phenotypes within the domains of social behavior, associative learning, motor function, epilepsy and sleep. Moreover, Grm7 knockout mice exhibit an attenuated response to amphetamine. These findings provide rationale for further investigation of mGlu₇ as a potential therapeutic target for neurodevelopmental disorders such as idiopathic autism, attention deficit hyperactivity disorder and Rett syndrome.     

Corticotropin-releasing Factor Receptor 2 Mediates Sex-Specific Cellular Stress Responses

Although females suffer twice as much as males from stress-related disorders, sex-specific participating and pathogenic cellular stress mechanisms remain uncharacterized. Using corticotropin-releasing factor receptor 2–deficient (Crhr2^−/− ) and wild-type (WT) mice, we show that CRF receptor type 2 (CRF₂) and its high-affinity ligand, urocortin 1 (Ucn1), are key mediators of the endoplasmic reticulum (ER) stress response in a murine model of acute pancreatic inflammation. Ucn1 was expressed de novo in acinar cells of male, but not female WT mice during acute inflammation. Upon insult, acinar Ucn1 induction was markedly attenuated in male but not female Crhr2^−/− mice. Crhr₂^−/− mice of both sexes show exacerbated acinar cell inflammation and necrosis. Electron microscopy showed mild ER damage in WT male mice and markedly distorted ER structure in Crhr2^−/− male mice during pancreatitis. WT and Crhr2^−/− female mice showed similarly distorted ER ultrastructure that was less severe than distortion seen in Crhr2^−/− male mice. Damage in ER structure was accompanied by increased ubiquitination, peIF2, and mistargeted localization of vimentin in WT mice that was further exacerbated in Crhr2^−/− mice of both sexes during pancreatitis. Exogenous Ucn1 rescued many aspects of histological damage and cellular stress response, including restoration of ER structure in male WT and Crhr2^−/−mice, but not in females. Instead, females often showed increased damage. Thus, specific cellular pathways involved in coping and resolution seem to be distinct to each sex. Our results demonstrate the importance of identifying sex-specific pathogenic mechanisms and their value in designing effective therapeutics.     

The Relative Expression of Mig6 and EGFR Is Associated with Resistance to EGFR Kinase Inhibitors

The sensitivity of only a few tumors to anti-epidermal growth factor receptor EGFR tyrosine kinase inhibitors (TKIs) can be explained by the presence of EGFR tyrosine kinase (TK) domain mutations. In addition, such mutations were rarely found in tumor types other than lung, such as pancreatic and head and neck cancer. In this study we sought to elucidate mechanisms of resistance to EGFR-targeted therapies in tumors that do not harbor TK sensitizing mutations in order to identify markers capable of guiding the decision to incorporate these drugs into chemotherapeutic regimens. Here we show that EGFR activity was markedly decreased during the evolution of resistance to the EGFR tyrosine kinase inhibitor (TKI) erlotinib, with a concomitant increase of mitogen-inducible gene 6 (Mig6), a negative regulator of EGFR through the upregulation of the PI3K-AKT pathway. EGFR activity, which was more accurately predicted by the ratio of Mig6/EGFR, highly correlated with erlotinib sensitivity in panels of cancer cell lines of different tissue origins. Blinded testing and analysis in a prospectively followed cohort of lung cancer patients treated with gefitinib alone demonstrated higher response rates and a marked increased in progression free survival for patients with a low Mig6/EGFR ratio (approximately 100 days, P = 0.01).     

Integrity of White Matter is Compromised in Mice with Hyaluronan Deficiency

Neurochemical Research - Brain white matter is the means of efficient signal propagation in brain and its dysfunction is associated with many neurological disorders. We studied the effect of...