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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1998

Overexpression of IGF-I in skeletal muscle of transgenic mice does not prevent unloading-induced atrophy

This study examined the association between local insulin-like growth factor I (IGF-I) overexpression and atrophy in skeletal muscle. We hypothesized that endogenous skeletal muscle IGF-I mRNA expression would decrease with hindlimb unloading (HU) in mice, and that transgenic mice overexpressing human IGF-I (hIGF-I) specifically in skeletal muscle would exhibit less atrophy after HU. Male transgenic mice and nontransgenic mice from the parent strain (FVB) were divided into four groups (n = 10/group): 1) transgenic, weight-bearing (IGF-I/WB); 2) transgenic, hindlimb unloaded (IGF-I/HU); 3) nontransgenic, weight-bearing (FVB/WB); and 4) nontransgenic, hindlimb unloaded (FVB/HU). HU groups were hindlimb unloaded for 14 days. Body mass was reduced (P < 0.05) after HU in both IGF-I (-9%) and FVB mice (-13%). Contrary to our hypothesis, we found that the relative abundance of mRNA for the endogenous rodent IGF-I (rIGF-I) was unaltered by HU in the gastrocnemius (GAST) muscle of wild-type FVB mice. High-level expression of hIGF-I peptide and mRNA was confirmed in the GAST and tibialis anterior (TA) muscles of the transgenic mice. Nevertheless, masses of the GAST and TA muscles were reduced (P < 0.05) in both FVB/HU and IGF-I/HU groups compared with FVB/WB and IGF-I/WB groups, respectively, and the percent atrophy in mass of these muscles did not differ between FVB and IGF-I mice. Therefore, skeletal muscle atrophy may not be associated with a reduction of endogenous rIGF-I mRNA level in 14-day HU mice. We conclude that high local expression of hIGF-I mRNA and peptide in skeletal muscle alone cannot attenuate unloading-induced atrophy of fast-twitch muscle in mice.

NASA Discipline Musculoskeletal↗
DOE OSTI2015

A pathophysiological role of TRPV1 in ischemic injury after transient focal cerebral ischemia in mice

Transient receptor potential vanilloid 1 (TRPV1) is a non-selective cation channel with high Ca{sup 2+} permeability, which functions as a polymodal nociceptor activated by heat, protons and several vanilloids, including capsaicin and anandamide. Although TRPV1 channels are widely distributed in the mammalian brain, their pathophysiological roles in the brain remain to be elucidated. In this study, we investigated whether TRPV1 is involved in cerebral ischemic injury using a middle cerebral artery (MCA) occlusion model in wild-type (WT) and TRPV1-knockout (KO) mice. For transient ischemia, the left MCA of C57BL/6 mice was occluded for 60 min and reperfused at 1 and 2 days after ischemia. We found that neurological and motor deficits, and infarct volumes in TRPV1-KO mice were lower than those of WT mice. Consistent with these results, intracerebroventricular injection of a TRPV1 antagonist, capsazepine (20 nmol), 30 min before the onset of ischemia attenuated neurological and motor deficits and improved infarct size without influencing cerebral blood flow in the occluded MCA territory. The protective effect of capsazepine on ischemic brain damage was not observed in TRPV1-KO mice. WT and TRPV1-KO mice did not show any differences with respect to the increased number of Iba1-positive microglia/macrophages, GFAP-positive astrocytes, and Gr1-positive neutrophils at 1 and 2 days after cerebral ischemia. Taken together, we conclude that brain TRPV1 channels are activated by ischemic stroke and cause neurological and motor deficits and infarction after brain ischemia. - Highlights: • We investigated whether TRPV1 is involved in transient ischemic brain damage in mice. • Neurological deficits and infarct volumes were lower in TRPV1-KO mice than in WT mice. • Injection of a TRPV1 antagonist, capsazepine, attenuated neurological deficits and improved infarct size. • No differences in astrocytic or microglial activation were observed between WT and TRPV1-KO mice.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Protective effects of SGLT2 inhibitor luseogliflozin on pancreatic β-cells in obese type 2 diabetic db/db mice

It is well known that Sodium-Glucose Co-transporter 2 (SGLT2) inhibitors, new hypoglycemic agents, improve glycemic control by increasing urine glucose excretion, but it remained unclear how they exert protective effects on pancreatic β-cells. In this study, we examined the effects of SGLT2 inhibitor luseogliflozin on β-cell function and mass using obese type 2 diabetic db/db mice. Ten-week-old male diabetic db/db mice were treated with luseogliflozin 0.0025% or 0.01% in chow (Luse 0.0025% or Luse 0.01%) or vehicle (control) for 4 weeks. Urinary glucose excretion was increased in Luse groups (0.0025% and 0.01%) compared to control mice 3 days after the intervention. Fasting blood glucose levels were significantly lower in mice treated with Luse compared to control mice. Fasting serum insulin concentrations were significantly higher in mice treated with Luse compared to control mice. Triglyceride levels tended to be lower in Luse groups compared to control mice. In immunohistochemical study using pancreas tissues, β-cell mass was larger in Luse groups compared to control group which was due to the increase of β-cell proliferation and decrease of β-cell apoptosis. Furthermore, in gene analysis using isolated islets, insulin 1, insulin 2, MafA, PDX-1 and GLUT2 gene expression levels were significantly higher in Luse groups compared to control group. In contrast, expression levels of fibrosis-related gene such as TGFβ, fibronectin, collagen I and collagen III were significantly lower in Luse groups. In conclusion, SGLT2 inhibitor luseogliflozin ameliorates glycemic control and thus exerts protective effects on pancreatic β-cell mass and function. - Highlights: • SGLT2 inhibitor luseogliflozin ameliorates glycemic control in db/db mice. • Luseogliflozin increases β-cell proliferation and decreases β-cell apoptosis. • Luseogliflozin preserves various β-cell-specific gene expression. • Luseogliflozin decreases various fibrosis-related factors in db/db mice.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

BA321, a novel carborane analog that binds to androgen and estrogen receptors, acts as a new selective androgen receptor modulator of bone in male mice

Carboranes are a class of carbon-containing polyhedral boron cluster compounds with globular geometry and hydrophobic surface that interact with hormone receptors such as estrogen receptor (ER) and androgen receptor (AR). We have synthesized BA321, a novel carborane compound, which binds to AR. We found here that it also binds to ERs, ERα and ERβ. In orchidectomized (ORX) mice, femoral bone mass was markedly reduced due to androgen deficiency and BA321 restored bone loss in the male, whilst the decreased weight of seminal vesicle in ORX mice was not recovered by administration of BA321. In female mice, BA321 acts as a pure estrogen agonist, and restored both the loss of bone mass and uterine atrophy due to estrogen deficiency in ovariectomized (OVX) mice. In bone tissues, the trabecular bone loss occurred in both ORX and OVX mice, and BA321 completely restored the trabecular bone loss in both sexes. Cortical bone loss occurred in ORX mice but not in OVX mice, and BA321 clearly restored cortical bone loss due to androgen deficiency in ORX mice. Therefore, BA321 is a novel selective androgen receptor modulator (SARM) that may offer a new therapy option for osteoporosis in the male. - Highlights: • A novel carborane compound BA321 binds to both AR and ERs, ERα and ERβ. • BA321 restores bone loss in orchidectomized mice without effects on sex organ. • BA321 acts as an estrogen agonist in bone and uterus in ovariectomized mice. • BA321 may be a new SARM to prevent the loss of musculoskeletal mass in elder men.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Progressive hearing loss and degeneration of hair cell stereocilia in taperin gene knockout mice

The TPRN gene encodes taperin, which is prominently present at the taper region of hair cell stereocilia. Mutations in TPRN have been reported to cause autosomal recessive nonsyndromic deafness 79(DFNB 79). To investigate the role of taperin in pathogenesis of hearing loss, we generated TPRN knockout mice using TALEN technique. Sanger sequencing confirmed an 11 bp deletion at nucleotide 177–187 in exon 1 of TPRN, which results in a truncated form of taperin protein. Heterozygous TPRN{sup +/−} mice showed apparently normal auditory phenotypes to their wide-type (WT) littermates. Homozygous TPRN{sup −/−} mice exhibited progressive sensorineural hearing loss as reflected by auditory brainstem response to both click and tone burst stimuli at postnatal days 15 (P15), 30 (P30), and 60 (P60). Alex Fluor-594 phalloidin labeling showed no obvious difference in hair cell numbers in the cochlea between TPRN{sup −/−} mice and WT mice under light microscope. However, scanning electronic microscopy revealed progressive degeneration of inner hair cell stereocilia, from apparently normal at postnatal days 3 (P3) to scattered absence at P15 and further to substantial loss at P30. The outer hair cell stereocilia also showed progressive degeneration, though much less severe, Collectively, we conclude that taperin plays an important role in maintenance of hair cell stereocilia. Establishment of TPRN knockout mice enables further investigation into the function of this gene. - Highlights: • TPRN{sup −/−} mice were generated using TALEN technique. • TPRN{sup −/−} mice presented progressive hearing loss. • WT and TPRN{sup −/−} mice showed no difference in hair cell numbers. • TPRN{sup −/−} mice showed progressive degeneration of hair cell stereocilia.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Overexpression of acetyl CoA carboxylase β exacerbates podocyte injury in the kidney of streptozotocin-induced diabetic mice

Highlights: • Podocyte-specific ACCβ overexpression causes severe podocyte injury in diabetic mice. • Podocyte-specific ACCβ overexpression increased proteinuria in diabetic mice. • AMPK activation ameliorates ACCβ overexpression-related podocyte injury. • Inhibition of ACCβ activity may serve as a therapy for diabetic nephropathy. A single nucleotide polymorphism (SNP) within the acetyl CoA carboxylase (ACC) β gene (ACACB), rs2268388, has been shown to be associated with susceptibility to development of proteinuria in patients with type 2 diabetes. To investigate the biological roles of ACCβ in the pathogenesis of diabetic nephropathy, we examined the effects of overexpression of ACACB using podocyte-specific ACACB-transgenic mice or ACACB-overexpressing murine podocytes. Podocyte-specific ACACB-transgenic mice or littermate mice were treated with streptozotocin (STZ) to induce diabetes, and 12 weeks after induction of diabetes, we examined the expression of podocyte markers to evaluate the degree of podocyte injury in these mice. We also examined the effects of ACCβ on podocyte injury in ACACB- or LacZ-overexpressing murine podocytes. Podocyte-specific ACACB overexpression did not cause visible podocyte injury in non-diabetic mice. In STZ-induced diabetic mice, ACACB-transgenic mice showed a significant increase in urinary albumin excretion, accompanied by decreased synaptopodin expression and podocin mislocalization in podocytes, compared with wild-type mice. In cultured murine podocytes, overexpression of ACACB significantly decreased synaptopodin expression and reorganized stress fibers under high glucose conditions, but not in normal glucose conditions. The decrease of synaptopodin expression and reorganized stress fibers observed in ACACB overexpressing cells cultured under high glucose conditions was reversed by a treatment of 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside (AICAR), activator of AMP-activated protein kinase (AMPK). The excess of ACCβ might contribute to exacerbation of podocyte injury in the kidney of an animal model for diabetes mellitus, and the AMPK/ACCβ pathway may be a novel therapeutic target for the prevention of diabetes-related podocyte injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Substance P preserves pancreatic β-cells in type 1 and type 2 diabetic mice

Highlights: • Substance P preserved β-cells in nonobese diabetic mice with type 1 diabetes. • Substance P preserved β-cells in db/db mice with type 2 diabetes. • Substance P inhibited the activation of pancreatic stellate cells. Preservation of pancreatic β-cells is required for the development of therapies for type 1 and type 2 diabetes (T1D and T2D, respectively). Our previous study demonstrated that substance P (SP) preserves β-cell populations in mice with streptozotocin-induced T1D. Here, we demonstrated that chronic systemic treatment with SP restored the mass of β-cells both in nonobese diabetic (NOD) mice with T1D or db/db mice with T2D. SP delayed the onset of T1D in NOD mice via immune modulation. SP inhibited immune infiltration into islets and the salivary glands of NOD mice. In db/db mice, SP treatment rescued glucose intolerance. Moreover, SP inhibited apoptosis, as well as the activation of pancreatic stellate cells in pancreatic islets of db/db mice. SP downregulated the number of α-smooth muscle actin (α-SMA) expressing cells in db/db pancreatic islets. Cleaved-caspase-3 expression was reduced in islets of SP-treated db/db mice compared to that in the control. Therefore, these results suggested that SP may preserve pancreatic β-cells through immune modulation and protection from the stimulated activation of pancreatic stellate cells and apoptosis in T1D and T2D, respectively.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Deficiency of unc-51 like kinase 1 (Ulk1) protects against mice traumatic brain injury (TBI) by suppression of p38 and JNK pathway

Highlights: • Ulk1-KO mice show reduced inflammation and apoptosis in hippocampus after TBI. • Ulk1-KO mice alleviate glial cells activation and autophagy in hippocampus of mice with TBI. • Ulk1 inhibition reduces inflammatory response, apoptosis and autophagy in LPS-stimulated astrocytes (AST) via p38/JNK pathway. Unc-51 like autophagy activating kinase 1 (Ulk1) is a serine/threonine kinase that plays a key role in regulating autophagy processes. We attempted to investigate the effects of Ulk1 on traumatic brain injury (TBI) progression by using wild type (WT) mice and Ulk1-knockout (KO) mice suffered with or not TBI. The results were verified using LPS-treated primary astrocyte (AST). Here, Ulk1 was over-expressed in hippocampus of WT mice after TBI, as well as in lipopolysaccharide (LPS)-stimulated AST. Ulk1-deletion improved cognitive ability and hippocampus histological changes in TBI mice. Nissl and neuronal nuclei (NeuN) staining indicated that Ulk1-deletion increased the number of surviving neurons in hippocampus of TBI mice. Ulk1-ablation alleviated neuroinflammation, as evidenced by the reduced expression of hippocampus pro-inflammatory cytokines in TBI mice. TBI-induced apoptosis was also ameliorated by Ulk1-ablation, as proved by the reduced number of TUNEL-staining cells, and cleaved Caspase-3 and poly (ADP-ribose) polymerase (PARP) expressions. Moreover, Ulk1-knockout suppressed TBI-stimulated activation of astrocytes and microglia cells. Additionally, hippocampus autophagy induced by TBI was attenuated by Ulk1-knockout. Further, TBI-activated p38/c-Jun N-terminal Kinase (JNK) pathway was repressed by Ulk1-deletion in hippocampus of mice. The findings above were confirmed in LPS-stimulated AST with or without Ulk1 siRNA transfection. Intriguingly, pre-treatment of p38 or JNK activator markedly abolished the anti-inflammation, anti-apoptosis and anti-autophagy effects of Ulk1-knockdown on LPS-incubated AST. In conclusion, our results demonstrated that Ulk1 might be a potential target for developing therapeutic strategy against TBI in future.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Ethanol metabolism, oxidative stress, and endoplasmic reticulum stress responses in the lungs of hepatic alcohol dehydrogenase deficient deer mice after chronic ethanol feeding

Consumption and over-consumption of alcoholic beverages are well-recognized contributors to a variety of pulmonary disorders, even in the absence of intoxication. The mechanisms by which alcohol (ethanol) may produce disease include oxidative stress and prolonged endoplasmic reticulum (ER) stress. Many aspects of these processes remain incompletely understood due to a lack of a suitable animal model. Chronic alcohol over-consumption reduces hepatic alcohol dehydrogenase (ADH), the principal canonical metabolic pathway of ethanol oxidation. We therefore modeled this situation using hepatic ADH-deficient deer mice fed 3.5% ethanol daily for 3 months. Blood ethanol concentration was 180 mg% in ethanol fed mice, compared to < 1.0% in the controls. Acetaldehyde (oxidative metabolite of ethanol) was minimally, but significantly increased in ethanol-fed vs. pair-fed control mice. Total fatty acid ethyl esters (FAEEs, nonoxidative metabolites of ethanol) were 47.6 μg/g in the lungs of ethanol-fed mice as compared to 1.5 μg/g in pair-fed controls. Histological and immunohistological evaluation showed perivascular and peribronchiolar lymphocytic infiltration, and significant oxidative injury, in the lungs of ethanol-fed mice compared to pair-fed controls. Several fold increases for cytochrome P450 2E1, caspase 8 and caspase 3 found in the lungs of ethanol-fed mice as compared to pair-fed controls suggest role of oxidative stress in ethanol-induced lung injury. ER stress and unfolded protein response signaling were also significantly increased in the lungs of ethanol-fed mice. Surprisingly, no significant activation of inositol-requiring enzyme-1α and spliced XBP1 was observed indicating a lack of activation of corrective mechanisms to reinstate ER homeostasis. The data suggest that oxidative stress and prolonged ER stress, coupled with formation and accumulation of cytotoxic FAEEs may contribute to the pathogenesis of alcoholic lung disease. - Highlights: • Chronic ethanol feeding causes oxidative stress, ER stress and inflammation in lungs of ADH– deer mice. • Chronic ethanol feeding generates FAEEs (nonoxidative metabolites of ethanol) in lungs of ADH– deer mice. • Chronic ethanol feeding induces CYP2E1 in the lungs of ADH– deer mice. • Lack of ER homeostasis due to a prolonged ethanol feeding could trigger inflammation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Hemizygosity of transsulfuration genes confers increased vulnerability against acetaminophen-induced hepatotoxicity in mice

The key mechanism for acetaminophen hepatotoxicity is cytochrome P450 (CYP)-dependent formation of N-acetyl-p-benzoquinone imine, a potent electrophile that forms protein adducts. Previous studies revealed the fundamental role of glutathione, which binds to and detoxifies N-acetyl-p-benzoquinone imine. Glutathione is synthesized from cysteine in the liver, and N-acetylcysteine is used as a sole antidote for acetaminophen poisoning. Here, we evaluated the potential roles of transsulfuration enzymes essential for cysteine biosynthesis, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH), in acetaminophen hepatotoxicity using hemizygous (Cbs{sup +/−} or Cth{sup +/−}) and homozygous (Cth{sup −/−}) knockout mice. At 4 h after intraperitoneal acetaminophen injection, serum alanine aminotransferase levels were highly elevated in Cth{sup −/−} mice at 150 mg/kg dose, and also in Cbs{sup +/−} or Cth{sup +/−} mice at 250 mg/kg dose, which was associated with characteristic centrilobular hepatocyte oncosis. Hepatic glutathione was depleted while serum malondialdehyde accumulated in acetaminophen-injected Cth{sup −/−} mice but not wild-type mice, although glutamate–cysteine ligase (composed of catalytic [GCLC] and modifier [GCLM] subunits) became more activated in the livers of Cth{sup −/−} mice with lower K{sub m} values for Cys and Glu. Proteome analysis using fluorescent two-dimensional difference gel electrophoresis revealed 47 differentially expressed proteins after injection of 150 mg acetaminophen/kg into Cth{sup −/−} mice; the profiles were similar to 1000 mg acetaminophen/kg-treated wild-type mice. The prevalence of Cbs or Cth hemizygosity is estimated to be 1:200–300 population; therefore, the deletion or polymorphism of either transsulfuration gene may underlie idiosyncratic acetaminophen vulnerability along with the differences in Cyp, Gclc, and Gclm gene activities. - Highlights: • Cbs{sup +/−}, Cth{sup +/−}, and especially Cth{sup −/−} mice were susceptible to APAP hepatic injury. • Hepatic glutathione became rapidly depleted upon APAP injection in Cth{sup −/−} mice. • Hepatic glutamate–cysteine ligase was activated by APAP injection and CTH deletion. • 2D DIGE identified 47 differentially expressed hepatic proteins by APAP injection. • Both transsulfuration enzymes are essential for protection against APAP injury.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Genetically obese (ob/ob) mice are resistant to the lethal effects of thioacetamide hepatotoxicity

Obesity increases the risk of chronic liver diseases, including viral hepatitis, alcohol-induced liver disease, and non-alcoholic steatohepatitis. In this study, we investigated the effects of obesity in acute hepatic failure using a murine model of thioacetamide (TA)-induced liver injury. Genetically obese ob/ob mice, together with non-obese ob/+ littermates, were subjected to a single intraperitoneal injection of TA, and examined for signs of hepatic injury. ob/ob mice showed a significantly higher survival rate, lower levels of serum alanine aminotransferase and aspartate aminotransferase, and less hepatic necrosis and apoptosis, compared with ob/+ mice. In addition, ob/ob mice exhibited significantly lower levels of malondialdehyde and significantly higher levels of glutathione and antioxidant enzyme activities compared with their ob/+ counterparts. Bioactivation analyses revealed reduced plasma clearance of TA and covalent binding of [{sup 14}C]TA to liver macromolecules in ob/ob mice. Together, these data demonstrate that genetically obese mice are resistant to TA-induced acute liver injury through diminished bioactivation of TA and antioxidant effects. - Highlights: • ob/ob mice are resistant to lethal doses of thioacetamide, compared to ob/+ mice. • ob/ob mice show reduced oxidative stress and enhanced antioxidant enzyme activity. • ob/ob mice exhibit diminished bioactivation of thioacetamide.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Bone-derived mesenchymal stromal cells from HIV transgenic mice exhibit altered proliferation, differentiation capacity and paracrine functions along with impaired therapeutic potential in kidney injury

Mesenchymal stem cells (MSCs) secrete paracrine factors that could be cytoprotective and serve roles in immunoregulation during tissue injury. Although MSCs express HIV receptors, and co-receptors, and are susceptible to HIV infection, whether HIV-1 may affect biological properties of MSCs needs more study. We evaluated cellular proliferation, differentiation and paracrine functions of MSCs isolated from compact bones of healthy control mice and Tg26 HIV-1 transgenic mice. The ability of MSCs to protect against cisplatin toxicity was studied in cultured renal tubular cells as well as in intact mice. We successfully isolated MSCs from healthy mice and Tg26 HIV-1 transgenic mice and found the latter expressed viral Nef, Vpu, NL4-3 and Vif genes. The proliferation and differentiation of Tg26 HIV-1 MSCs was inferior to MSCs from healthy mice. Moreover, transplantation of Tg26 HIV-1 MSCs less effectively improved outcomes compared with healthy MSCs in mice with acute kidney injury. Also, Tg26 HIV-1 MSCs secreted multiple cytokines, but at significantly lower levels than healthy MSCs, which resulted in failure of conditioned medium from these MSCs to protect cultured renal tubular cells from cisplatin toxicity. Therefore, HIV-1 had adverse biological effects on MSCs extending to their proliferation, differentiation, function, and therapeutic potential. These findings will help in advancing mechanistical insight in renal injury and repair in the setting of HIV-1 infection. -- Highlights: •MSCs isolated from HIV mice displayed HIV genes. •MSCs isolated from HIV mice exhibited attenuated growth and paracrine functions. •AKI mice with transplanted HIV-MSC displayed poor outcome. •HIV-1 MSC secreted multiple cytokines but at a lower level.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Lentivirus-mediated CTRP6 silencing ameliorates diet-induced obesity in mice

Highlights: • The knockdown of CTRP6 reduced both body weight and white adipose tissue of mice. • CTRP6 knockdown decreased the serum TG and improved the insulin sensitivity in mice. • The knockdown of CTRP6 promoted brown adipogenesis both in mice and in adipocytes. • CTRP6 knockdown activated p38MAPK but inhibited Hh signaling pathway in adipocytes. The C1q/TNF-related protein 6 (CTRP6) is an adipokine involved in diverse biological processes. Formerly, we identified that CTRP6 regulates adipocyte differentiation, fatty acid oxidation and triglyceride accumulation in vitro. However, the effects of CTRP6 on adiposity in vivo have not yet been defined. This study aimed to confirm the involvement of CTRP6 in adipose accumulation and brown adipogenesis by intraperitoneal injection of the CTRP6-shRNA lentivirus into mice (CL mice). CL mice were significantly thinner than the control mice after feeding with a high fat diet (HFD), independent of food intake quantity. These HFD-fed CL mice displayed lower white and brown adipocyte sizes, and serum leptin levels, but an increase in serum adiponectin and insulin sensitivity relative to control mice. Additionally, the brown fat markers, such as UCP1, PRDM16, PGC1α and Cidea were found to be upregulated in the white and brown adipose tissue of the CL mice. These markers were also upregulated in a primary culture of mouse white and brown adipocytes treated with the CTRP6-shRNA lentivirus. Mechanistically, the knockdown of CTRP6 increased p38MAPK phosphorylation, but decreased expression of proteins involved in the Hedgehog signaling pathway (Sufu, Gli2 and Gli3). CTRP6 knockdown also upregulated expression of mitochondrial metabolic factors NRF-1, TFAM, CPT1 and Cyt C. Data from the current study show that CTRP6 knockdown protects against diet-induced obesity and promotes brown adipogenesis by the p38MAPK/Hh signaling pathway in conjunction with the upregulation of brown fat markers and mitochondrial metabolic factors.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2003

Role of major histocompatibility complex class II in resistance of mice to naturally acquired infection with Syphacia obvelata

Genetics plays a substantial role in host resistance in many host-parasite interactions. We examined the prevalence of naturally acquired infection with Syphacia obvelata in a number of mouse strains housed in a non-barrier facility. These mice, which included cross-bred and congenic, inbred strains on various genetic backgrounds, differ in the loci for the immune function genes--major histocompatibility complex class II (MHCII), toll-like receptor 4 (Tlr4), and solute carrier family 11, member 1 (Slc11a1)--which allowed comparisons of the impact of these genes on resistance to pinworm infection. Male and female mice of various ages were sampled over an 18-month period; infection was determined by use of the cellophane tape test. Results indicated that mice that were MHCII+/+ had a significantly lower prevalence of infection than did mice that were MHCII-/-. Differences were not seen between male and female mice. Although MHCII+/+ mice had an age-associated decrease in infection prevalence, such decrease was not seen in MHCII-/- mice. In contrast, infection prevalence in mice with the normal Tlr4 gene (Tlr4(LPS-n/LPS-n)) gene did not differ significantly compared with that in mice that were homozygous for either the point mutation (Tlr4(LPS-d/LPS-d)) or deletion (Tlr4(LPS-del/LPS-del)) of that gene. Likewise, the presence (Sle11a1r/r) or absence (Slc11a1s/s) of functional alleles for Slc11a1 had no effect on the prevalence of infection with S. obvelata. In conclusion, presence of MHCII, but not Tlr4 or Slc11a1 significantly influences prevalence of naturally acquired infection with S. obvelata. These data justify further comprehensive analyses of the immune components that are involved in pinworm resistance.

Non-NASA Center↗
DOE OSTI2015

Constitutive phosphorylation of cardiac myosin regulatory light chain prevents development of hypertrophic cardiomyopathy in mice

Myosin light chain kinase (MLCK)-dependent phosphorylation of the regulatory light chain (RLC) of cardiac myosin is known to play a beneficial role in heart disease, but the idea of a phosphorylation-mediated reversal of a hypertrophic cardiomyopathy (HCM) phenotype is novel. Our previous studies on transgenic (Tg) HCM-RLC mice revealed that the D166V (Aspartate166 →Valine) mutation-induced changes in heart morphology and function coincided with largely reduced RLC phosphorylation in situ. In this paper, we hypothesized that the introduction of a constitutively phosphorylated Serine15 (S15D) into the hearts of D166V mice would prevent the development of a deleterious HCM phenotype. In support of this notion, MLCK-induced phosphorylation of D166V-mutated hearts was found to rescue some of their abnormal contractile properties. Tg-S15D-D166V mice were generated with the human cardiac RLC-S15D-D166V construct substituted for mouse cardiac RLC and were subjected to functional, structural, and morphological assessments. The results were compared with Tg-WT and Tg-D166V mice expressing the human ventricular RLC-WT or its D166V mutant, respectively. Echocardiography and invasive hemodynamic studies demonstrated significant improvements of intact heart function in S15D-D166V mice compared with D166V, with the systolic and diastolic indices reaching those monitored in WT mice. A largely reduced maximal tension and abnormally high myofilament Ca 2+ sensitivity observed in D166V-mutated hearts were reversed in S15D-D166V mice. Low-angle X-ray diffraction study revealed that altered myofilament structures present in HCM-D166V mice were mitigated in S15D-D166V rescue mice. Finally, our collective results suggest that expression of pseudophosphorylated RLC in the hearts of HCM mice is sufficient to prevent the development of the pathological HCM phenotype.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Bile acids override steatosis in farnesoid X receptor deficient mice in a model of non-alcoholic steatohepatitis

Highlights: • FXR deficiency enhanced MCD diet-induced hepatic fibrosis. • FXR deficiency attenuated MCD diet-induced hepatic steatosis. • FXR deficiency repressed genes involved in fatty acid uptake and triglyceride accumulation. - Abstract: Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases, and the pathogenesis is still not well known. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily and plays an essential role in maintaining bile acid and lipid homeostasis. In this study, we study the role of FXR in the pathogenesis of NFALD. We found that FXR deficient (FXR{sup −/−}) mice fed methionine- and choline-deficient (MCD) diet had higher serum ALT and AST activities and lower hepatic triglyceride levels than wild-type (WT) mice fed MCD diet. Expression of genes involved in inflammation (VCAM-1) and fibrosis (α-SMA) was increased in FXR{sup −/−} mice fed MCD diet (FXR{sup −/−}/MCD) compared to WT mice fed MCD diet (WT/MCD). Although MCD diet significantly induced hepatic fibrosis in terms of liver histology, FXR{sup −/−}/MCD mice showed less degree of hepatic steatosis than WT/MCD mice. Moreover, FXR deficiency synergistically potentiated the elevation effects of MCD diet on serum and hepatic bile acids levels. The super-physiological concentrations of hepatic bile acids in FXR{sup −/−}/MCD mice inhibited the expression of genes involved in fatty acid uptake and triglyceride accumulation, which may be an explanation for less steatosis in FXR{sup −/−}/MCD mice in contrast to WT/MCD mice. These results suggest that hepatic bile acids accumulation could override simple steatosis in hepatic injury during the progression of NAFLD and further emphasize the role of FXR in maintaining hepatic bile acid homeostasis in liver disorders and in hepatic protection.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Loss of Dok-1 and Dok-2 in mice causes severe experimental colitis accompanied by reduced expression of IL-17A and IL-22

Appropriate immune responses and mucosal barrier functions are required for the maintenance of intestinal homeostasis. Defects in this defense system may lead to inflammatory disorders such as inflammatory bowel disease. Downstream of tyrosine kinases 1 (Dok-1) and its closest homolog, Dok-2, are preferentially expressed in immune cells, and play essential roles in the negative regulation of multiple signaling pathways in both innate and adaptive immunity. However, the function of these proteins in intestinal homeostasis remained unclear. Here we show that Dok-1/-2 double knockout (DKO) mice were highly susceptible to dextran sodium sulfate (DSS)-induced colitis compared with Dok-1 or Dok-2 single KO and wild type (WT) mice. Furthermore, DSS-treated Dok-1/-2 DKO mice exhibited increased colonic tissue damage accompanied by reduced proliferation of the epithelial cells relative to WT controls, suggesting that Dok-1/-2 DKO mice have defects in the repair of intestinal epithelial lesions. In addition, the levels of the Th17 cytokines IL-17A and IL-22, which have protective roles in DSS-induced colitis, were reduced in DSS-treated Dok-1/-2 DKO mice compared with WT mice. Taken together, our results demonstrate that Dok-1 and Dok-2 negatively regulate intestinal inflammation, apparently through the induction of IL-17A and IL-22 expression. - Highlights: • Dok-1 and Dok-2 play a cooperative role in protection against DSS-induced colitis. • Dok-1/-2 double KO (DKO) mice show extensive ulceration of the colon after DSS treatment. • Proliferation of colonic epithelium is inhibited in DSS-treated Dok-1/-2 DKO mice. • Expression of IL-17A and IL-22 is reduced in the colon of DSS-treated Dok-1/-2 DKO mice.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

NLRP1 deficiency attenuates diabetic retinopathy (DR) in mice through suppressing inflammation response

Highlights: • NLRP1 expression was increased in retina of diabetic mice. • NLRP1 deletion attenuates STZ-induced diabetic retinopathy. • Knockout of NLRP1 reduces inflammation and alleviates diabetic retinopathy in STZ mice. • Suppression of NLRP1 restrains inflammation in high fructose-incubated retinal ganglion cells. Diabetic retinopathy (DR) is the common cause of diabetic vascular complications. The NOD-like receptor (NLR) family, pyrin domain containing 1 (NLRP1), also known as NALP1, inflammasome is the first member of the NLR family to be discovered, playing an important role in inflammatory response. However, its effect on DR development has not been reported. In the study, the wild type (WT) and NLRP1{sup −/−} mice were injected with streptozotocin (STZ) to induce DR. The results indicated that NLRP1{sup −/−} significantly increased bodyweight reduction and decreased blood glucose levels induced by STZ. WT/DR mice exhibited higher levels of NLRP1 in retinas. NLRP1{sup −/−} ameliorated retinal abnormalities in DR mice using H&E staining. In addition, attenuated avascular areas and neovascular tufts were also observed in NLRP1{sup −/−}/DR mice. The levels of pro-inflammatory cytokines in serum and retinas were highly induced in WT/DR mice, whereas being markedly reduced by NLRP1{sup −/−}. In addition, vascular endothelial growth factor (VEGF) and Iba1 expressions induced by STZ in serum or retinas were significantly down-regulated in NLRP1{sup −/−}/DR mice. Consistently, NLRP1{sup −/−} attenuated ASC and Caspase-1 expressions in retinas of DR mice. Compared to WT/DR group, NLRP1{sup −/−} markedly decreased retina p-nuclear factor-κB (NF-κB), interleukin-1β (IL-1β) and IL-18 levels. And similar results were confirmed in vitro that suppressing NLRP1/ASC inflammasome ameliorated inflammatory response in fructose-treated retinal ganglion cells. The results above indicated that the modulation of NLRP1 inflammasome might be a promising strategy for DR therapy.

60 APPLIED LIFE SCIENCES↗