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Antiadipogenic effects of a standardized quassinoids-enriched fraction and eurycomanone from Eurycoma longifolia

Balan D, Chan KL, Murugan D, AbuBakar S, Wong PF

Phytother Res, 2018 Jul;32(7):1332-1345.
PMID: 29520860 DOI: 10.1002/ptr.6065

Bioactive compounds of Eurycoma longifolia (EL) jack were previously shown to reduce omentum fat mass and oestradiol-induced fatty uterine adhesion in rats. However, the exact role of EL on adipogenesis remains unknown. This study sought to investigate the effects of an EL standardized quassinoids-enriched fraction (SQEL) and the pure compound, eurycomanone, on adipogenesis in 3T3-L1 preadipocyte cells. 3T3-L1 cells were induced to differentiate and treated for 8 days. The treatment reduced intracellular accumulation of lipid droplets and triglycerides in the differentiating adipocytes and induced lipolysis in matured adipocytes. The expressions of adipogenic transcription factors and markers were also significantly downregulated during the early stage of differentiation. Furthermore, SQEL also suppressed body weight gain, decreased epididymal and perirenal fat pad mass and size, and reduced the accumulation of fat in the livers of C57BL/6J mice fed with normal or high-fat diet that were concurrently given 5 mg/kg and 10 mg/kg (i.p) of SQEL for 12 weeks. SQEL also improved glucose intolerance and decreased the elevated total cholesterol and triglyceride levels in these mice groups. These findings suggest that SQEL could be explored as an alternative pharmacologic agent inhibiting adipogenesis for the prevention of obesity.

Matched MeSH terms: Mice, Inbred C57BL
Preventive mechanisms of Chinese Tibetan medicine Triphala against nonalcoholic fatty liver disease

Jiang Y, Zhao L, Ma J, Yang Y, Zhang B, Xu J, et al.

Phytomedicine, 2024 Jan;123:155229.
PMID: 38006804 DOI: 10.1016/j.phymed.2023.155229

BACKGROUND: Triphala (TLP), as a Chinese Tibetan medicine composing of Emblica officinalis, Terminalia chebula and Terminalia bellirica (1.2:1.5:1), exhibited hepatoprotective, hypolipidemic and gut microbiota modulatory effects. Nonetheless, its roles in prevention of high-fat diet (HFD)-induced nonalcoholic fatty liver disease (NAFLD) and the related mechanistic insights involving the interplay of gut microbiota and hepatic inflammation are not known.
PURPOSE: The present study seeks to determine if TLP would prevent HFD-induced NAFLD in vivo and its underlying mechanisms from the perspectives of gut microbiota, metabolites, and hepatic inflammation.
METHODS: TLP was subjected to extraction and chemo-profiling, and in vivo evaluation in HFD-fed rats on hepatic lipid and inflammation, intestinal microbiota, short-chain fatty acids (SCFAs) and permeability, and body weight and fat content profiles.
RESULTS: The TLP was primarily constituted of gallic acid, corilagin and chebulagic acid. Orally administered HFD-fed rats with TLP were characterized by the growth of Ligilactobacillus and Akkermansia, and SCFAs (acetic/propionic/butyric acid) secretion which led to increased claudin-1 and zonula occludens-1 expression that reduced the mucosal permeability to migration of lipopolysaccharides (LPS) into blood and liver. Coupling with hepatic cholesterol and triglyceride lowering actions, the TLP mitigated both inflammatory (ALT, AST, IL-1β, IL-6 and TNF-α) and pro-inflammatory (TLR4, MYD88 and NF-κB P65) activities of liver, and sequel to histopathological development of NAFLD in a dose-dependent fashion.
CONCLUSION: TLP is promisingly an effective therapy to prevent NAFLD through modulating gut microbiota, mucosal permeability and SCFAs secretion with liver fat and inflammatory responses.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext "A Step and a Ceiling": mechanical properties of Ca2+ spark vasoregulation in resistance arteries by pressure-induced oxidative activation of PKG

Csato V, Kadir SZSA, Khavandi K, Bennett H, Sugden S, Gurney AM, et al.

Physiol Rep, 2019 Nov;7(22):e14260.
PMID: 31782255 DOI: 10.14814/phy2.14260

We investigated the biomechanical relationship between intraluminal pressure within small mesenteric resistance arteries, oxidant activation of PKG, Ca2+ sparks, and BK channel vasoregulation. Mesenteric resistance arteries from wild type (WT) and genetically modified mice with PKG resistance to oxidative activation were studied using wire and pressure myography. Ca2+ sparks and Ca2+ transients within vascular smooth muscle cells of intact arteries were characterized using high-speed confocal microscopy of intact arteries. Arteries were studied under conditions of varying intraluminal pressure and oxidation. Intraluminal pressure specifically, rather than the generic stretch of the artery, was necessary to activate the oxidative pathway. We demonstrated a graded step activation profile for the generation of Ca2+ sparks and also a functional "ceiling" for this pressure --sensitive oxidative pathway. During steady state pressure - induced constriction, any additional Ca2+ sensitive-K+ channel functional availability was independent of oxidant activated PKG. There was an increase in the amplitude, but not the Area under the Curve (AUC) of the caffeine-induced Ca2+ transient in pressurized arteries from mice with oxidant-resistant PKG compared with wild type. Overall, we surmise that intraluminal pressure within resistance arteries controls Ca2+ spark vasoregulation through a tightly controlled pathway with a graded onset switch. The pathway, underpinned by oxidant activation of PKG, cannot be further boosted by additional pressure or oxidation once active. We propose that these restrictive characteristics of pressure-induced Ca2+ spark vasoregulation confer stability for the artery in order to provide a constant flow independent of additional pressure fluctuations or exogenous oxidants.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Effects of ageing on pro-arrhythmic ventricular phenotypes in incrementally paced murine Pgc-1β -/- hearts

Ahmad S, Valli H, Edling CE, Grace AA, Jeevaratnam K, Huang CL

Pflugers Arch., 2017 Dec;469(12):1579-1590.
PMID: 28821956 DOI: 10.1007/s00424-017-2054-3

A range of chronic clinical conditions accompany cardiomyocyte energetic dysfunction and constitute independent risk factors for cardiac arrhythmia. We investigated pro-arrhythmic and arrhythmic phenotypes in energetically deficient C57BL mice with genetic ablation of the mitochondrial promoter peroxisome proliferator-activated receptor-γ coactivator-1β (Pgc-1β), a known model of ventricular arrhythmia. Pro-arrhythmic and cellular action potential (AP) characteristics were compared in intact Langendorff-perfused hearts from young (12-16 week) and aged (> 52 week), wild-type (WT) and Pgc-1β -/- mice. Simultaneous electrocardiographic and intracellular microelectrode recordings were made through successive trains of 100 regular stimuli at progressively incremented heart rates. Aged Pgc-1β -/- hearts displayed an increased incidence of arrhythmia compared to other groups. Young and aged Pgc-1β -/- hearts showed higher incidences of alternans in both AP activation (maximum AP upshoot velocity (dV/dt)max and latency), recovery (action potential duration (APD90) and resting membrane potential (RMP) characteristics compared to WT hearts. This was particularly apparent at lower pacing frequencies. These findings accompanied reduced (dV/dt)max and increased AP latency values in the Pgc-1β -/- hearts. APs observed prior to termination of the protocol showed lower (dV/dt)max and longer AP latencies, but indistinguishable APD90 and RMPs in arrhythmic compared to those in non-arrhythmic hearts. APD restitution analysis showed that Pgc-1β -/- and WT hearts showed similar limiting gradients. However, Pgc-1β -/- hearts had shortened plateau AP wavelengths, particularly in aged Pgc-1β -/- hearts. Pgc-1β -/- hearts therefore show pro-arrhythmic instabilities attributable to altered AP conduction and activation rather than recovery characteristics.

Matched MeSH terms: Mice, Inbred C57BL
Caffeic acid phenethyl ester (CAPE) reverses fibrosis caused by chronic colon inflammation in murine model of colitis

Tambuwala MM, Kesharwani P, Shukla R, Thompson PD, McCarron PA

Pathol Res Pract, 2018 Nov;214(11):1909-1911.
PMID: 30170869 DOI: 10.1016/j.prp.2018.08.020

Fibrosis is known to be the hallmarks of chronic inflammation of the bowel. Epithelial damage due to inflammation compromises the barrier function of the gastrointestinal tract. This barrier dysfunction leads to further spread of inflammation resulting in a chronic state of inflammation. This chronic inflammation leads to development of fibrosis, which has very limited therapeutic options and usually requires surgical removal of the affected tissue. Our previous work has shown that Caffeic acid phenethyl ester (CAPE) is a naturally occurring anti-inflammatory agent, found in propolis, has been found to be protective in experimental colitis via enhancement of epithelial barrier function. However, the impact of CAPE on resolution of fibrosis in the long-term is unknown. The aim of this follow up study was to investigate the effect of CAPE on colon fibrosis in a chronic model of Dextran sulphate sodium induced colitis in mice. Dextran sulphate sodium (DSS) 2.5% w/v was administered in drinking water to induce colitis in C57/BL6 mice for 5 days on the 6th day DSS was stopped and test group mice were treated with intraperitoneal administration of CAPE (30 mg kg-1 day-1) for a further 7 days. Disease activity index (DAI) score, colon length and tissue histology and level of tissue fibrosis was observed. CAPE-treated mice had significantly lower levels of DAI, tissue inflammation scores and fibrosis as compared with control group. Our results show that CAPE is effective in resolving colon fibrosis in chronic inflammation. Thus, we can conclude CAPE could be a potential therapeutic agent for further clinical investigations for treatment of fibrosis in inflammatory bowel diseases in humans.

Matched MeSH terms: Mice, Inbred C57BL
Immune Stimulation of RAP domain binding protein (rTgRA15) from Toxoplasma gondii

Lew MH, Noordin R, Monsur Alam Khan M, Tye GJ

Pathog Glob Health, 2018 10;112(7):387-394.
PMID: 30332344 DOI: 10.1080/20477724.2018.1536854

Toxoplasmosis, a parasitic disease in human and animals, is caused by Toxoplasma gondii. Our previous study has led to the discovery of a novel RAP domain binding protein antigen (TgRA15), an apparent in-vivo induced antigen recognised by antibodies in acutely infected individuals. This study is aimed to evaluate the humoral response and cytokine release elicited by recombinant TgRA15 protein in C57BL/6 mice, demonstrating its potential as a candidate vaccine for Toxoplasma gondii infection. In this study, the recombinant TgRA15 protein was expressed in Escherichia coli, purified and refolded into soluble form. C57BL/6 mice were immunised intradermally with the antigen and CASAC (Combined Adjuvant for Synergistic Activation of Cellular immunity). Antigen-specific humoral and cell-mediated responses were evaluated using Western blot and ELISA. The total IgG, IgG1 and IgG2a antibodies specific to the antigen were significantly increased in treatment group compare to control group. A higher level of interferon gamma (IFN-γ) secretion was demonstrated in the mice group receiving booster doses of rTgRA15 protein, suggesting a potential Th1-mediated response. In conclusion, the rTgRA15 protein has the potential to generate specific antibody response and elicit cellular response, thus potentially serve as a vaccine candidate against T. gondii infection.

Matched MeSH terms: Mice, Inbred C57BL
Intraspecific variation of Taenia taeniaeformis as determined by various criteria

Azuma H, Okamoto M, Oku Y, Kamiya M

Parasitol Res, 1995;81(2):103-8.
PMID: 7731915

The intraspecific variation of four laboratory-reared isolates of Taenia taeniaformis the SRN and KRN isolates from Norway rats, Rattus norvegicus, captured in Japan and Malaysia, respectively; the BMM isolated from a house mouse, Mus musculus, captured in Belgium; and the ACR isolate from a gray red-backed vole, Clethrionomys rufocanus bedfordiae, captured in Japan was examined by various criteria. Eggs of each of the four isolates were orally inoculated into several species of intermediate host. They were most infective to the rodent species from which the original metacestode of each isolate had been isolated in the field, and only the ACR isolate was infective to the gray red-backed vole. Although little difference was found between the SRN, KRN, and BMM isolates by the other criteria, including the morphology of rostellar hooks, the protein composition of the metacestode, and restriction endonuclease analysis of DNA, the ACR isolate was clearly different from the others. It was considered that the ACR isolate was independent as a strain distinct from the other three isolates.

Matched MeSH terms: Mice, Inbred C57BL/parasitology
Fulltext Interferon-stimulated gene of 20 kDa protein (ISG20) degrades RNA of hepatitis B virus to impede the replication of HBV in vitro and in vivo

Leong CR, Funami K, Oshiumi H, Mengao D, Takaki H, Matsumoto M, et al.

Oncotarget, 2016 10 18;7(42):68179-68193.
PMID: 27626689 DOI: 10.18632/oncotarget.11907

Hepatitis B virus (HBV) barely induces host interferon (IFN)-stimulated genes (ISGs), which allows efficient HBV replication in the immortalized mouse hepatocytes as per human hepatocytes. Here we found that transfection of Isg20 plasmid robustly inhibits the HBV replication in HBV-infected hepatocytes irrespective of IRF3 or IFN promoter activation. Transfection of Isg20 is thus effective to eradicate HBV in the infected hepatocytes. Transfection of HBV genome or ε-stem of HBV pgRNA (active pgRNA moiety) failed to induce Isg20 in the hepatocytes, while control polyI:C (a viral dsRNA analogue mimic) activated MAVS pathway leading to production of type I IFN and then ISGsg20 via the IFN-α/β receptor (IFNAR). Consistently, addition of IFN-α induced Isg20 and partially suppressed HBV replication in hepatocytes. Chasing HBV RNA, DNA and proteins by blotting indicated that ISG20 expression decreased HBV RNA and replicative DNA in HBV-transfected cells, which resulted in low HBs antigen production and virus titer. The exonuclease domains of ISG20 mainly participated in HBV-RNA decay. In vivo hydrodynamic injection, ISG20 was crucial for suppressing HBV replication without degrading host RNA in the liver. Taken together, ISG20 acts as an innate anti-HBV effector that selectively degrades HBV RNA and blocks replication of infectious HBV particles. ISG20 would be a critical effector for ameliorating chronic HBV infection in the IFN therapy.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext The Effect of Isoleucine Supplementation on Body Weight Gain and Blood Glucose Response in Lean and Obese Mice

O'Rielly R, Li H, Lim SM, Yazbeck R, Kritas S, Ullrich SS, et al.

Nutrients, 2020 Aug 14;12(8).
PMID: 32823899 DOI: 10.3390/nu12082446

Chronic isoleucine supplementation prevents diet-induced weight gain in rodents. Acute-isoleucine administration improves glucose tolerance in rodents and reduces postprandial glucose levels in humans. However, the effect of chronic-isoleucine supplementation on body weight and glucose tolerance in obesity is unknown. This study aimed to investigate the impact of chronic isoleucine on body weight gain and glucose tolerance in lean and high-fat-diet (HFD) induced-obese mice. Male C57BL/6-mice, fed a standard-laboratory-diet (SLD) or HFD for 12 weeks, were randomly allocated to: (1) Control: Drinking water; (2) Acute: Drinking water with a gavage of isoleucine (300 mg/kg) prior to the oral-glucose-tolerance-test (OGTT) or gastric-emptying-breath-test (GEBT); (3) Chronic: Drinking water with 1.5% isoleucine, for a further six weeks. At 16 weeks, an OGTT and GEBT was performed and at 17 weeks metabolic monitoring. In SLD- and HFD-mice, there was no difference in body weight, fat mass, and plasma lipid profiles between isoleucine treatment groups. Acute-isoleucine did not improve glucose tolerance in SLD- or HFD-mice. Chronic-isoleucine impaired glucose tolerance in SLD-mice. There was no difference in gastric emptying between any groups. Chronic-isoleucine did not alter energy intake, energy expenditure, or respiratory quotient in SLD- or HFD-mice. In conclusion, chronic isoleucine supplementation may not be an effective treatment for obesity or glucose intolerance.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext A Pilot Study on Anti-Obesity Mechanisms of KappaphycusAlvarezii: The Role of Native κ-Carrageenan and the Leftover Sans-Carrageenan Fraction

Chin YX, Mi Y, Cao WX, Lim PE, Xue CH, Tang QJ

Nutrients, 2019 May 21;11(5).
PMID: 31117266 DOI: 10.3390/nu11051133

Kappaphycus is a commercially important edible red alga widely cultivated for carrageenan production. Here, we aimed to investigate the anti-obesity mechanism of Kappaphycusalvarezii by comparing the effects of whole seaweed (T), extracted native κ-carrageenan (CGN), and the leftover fraction sans-carrageenan (SCGN) supplementations (5%, w/w) on diet-induced obese C57BL/6J mice. A high-fat diet induced both a raised body fat percentage and serum cholesterol level, increased adipocytes size, abnormal levels of adipocytokines, and promoted gut dysbiosis. Our results showed that, overall, both CGN and SCGN were more effective in reversing obesity and related metabolic syndromes to normal levels than T. Furthermore, these findings suggested that CGN- and SCGN-modulated gut dysbiosis induced by a high-fat diet, which may play an influencing role in adiponectin dysregulation. Our data also showed some evidence that CGN and SCGN have distinct effects on selected genes involved in lipid metabolism. In conclusion, both κ-carrageenan and SCGN have novel anti-obesity potential with possible different mechanisms of action.

Matched MeSH terms: Mice, Inbred C57BL
siRNA Blocking of Mammalian Target of Rapamycin (mTOR) Attenuates Pathology in Annonacin-Induced Tauopathy in Mice

Salama M, El-Desouky S, Alsayed A, El-Hussiny M, Magdy K, Fekry E, et al.

Neurotox Res, 2019 May;35(4):987-992.
PMID: 30362086 DOI: 10.1007/s12640-018-9974-3

Tauopathy is a pathological hallmark of many neurodegenerative diseases. It is characterized by abnormal aggregates of pathological phosphotau and somatodendritic redistribution. One suggested strategy for treating tauopathy is to stimulate autophagy, hence, getting rid of these pathological protein aggregates. One key controller of autophagy is mTOR. Since stimulation of mTOR leads to inhibition of autophagy, inhibitors of mTOR will cause stimulation of autophagy process. In this report, tauopathy was induced in mice using annonacin. Blocking of mTOR was achieved through stereotaxic injection of siRNA against mTOR. The behavioral and immunohistochemical evaluation revealed the development of tauopathy model as proven by deterioration of behavioral performance in open field test and significant tau aggregates in annonacin-treated mice. Blocking of mTOR revealed significant clearance of tau aggregates in the injected side; however, tau expression was not affected by mTOR blockage.

Matched MeSH terms: Mice, Inbred C57BL
Transcriptome composition of the preoptic area in mid-age and escitalopram treatment in male mice

Moriya S, Soga T, Wong DW, Parhar IS

Neurosci Lett, 2016 May 27;622:67-71.
PMID: 27113202 DOI: 10.1016/j.neulet.2016.04.052

The decrease in serotonergic neurotransmission during aging can increase the risk of neuropsychiatric diseases such as depression in elderly population and decline the reproductive system. Therefore, it is important to understand the age-associated molecular mechanisms of brain aging. In this study, the effect of aging and chronic escitalopram (antidepressant) treatment to admit mice was investigated by comparing transcriptomes in the preoptic area (POA) which is a key nucleus for reproduction. In the mid-aged brain, the immune system-related genes were increased and hormone response-related genes were decreased. In the escitalopram treated brains, transcription-, granule cell proliferation- and vasoconstriction-related genes were increased and olfactory receptors were decreased. Since homeostasis and neuroprotection-related genes were altered in both of mid-age and escitalopram treatment, these genes could be important for serotonin related physiologies in the POA.

Matched MeSH terms: Mice, Inbred C57BL
Early-life citalopram-induced impairments in sexual behavior and the role of androgen receptor

Soga T, Wong DW, Putteeraj M, Song KP, Parhar IS

Neuroscience, 2012 Dec 6;225:172-84.
PMID: 22960312 DOI: 10.1016/j.neuroscience.2012.08.061

Postnatal treatment with selective serotonin reuptake inhibitors (SSRIs) has been found to affect brain development and the regulation of reproduction in rodent models. The normal masculinization process in the brain requires a transient decrease in serotonin (5-HT) levels in the brain during the second postnatal week. Strict regulation of androgen receptor (AR) and gonadotropin-releasing hormone (GnRH) expression is important to control male reproductive activity. Therefore, this study was designed to examine the effects of a potent SSRI (citalopram) on male sexual behavior and expression levels of AR and GnRH in adult male mice receiving either vehicle or citalopram (10mg/kg) daily during postnatal days 8-21. The citalopram-treated male mice showed altered sexual behavior, specifically a significant reduction in the number of intromissions preceding ejaculation compared with the vehicle-treated mice. The citalopram-treated male mice displayed elevated anxiety-like behavior in an open field test and lower locomotor activity in their home cage during the subjective night. Although there was no change in GnRH and AR mRNA levels in the preoptic area (POA), quantified by real-time polymerase chain reaction, immunostained AR cell numbers in the medial POA were decreased in the citalopram-treated male mice. These results suggest that the early-life inhibition of 5-HT transporters alters the regulation of AR expression in the medial POA, likely causing decreased sexual behavior and altered home cage activity in the subjective night.

Matched MeSH terms: Mice, Inbred C57BL
Neonatal dexamethasone exposure down-regulates GnRH expression through the GnIH pathway in female mice

Soga T, Dalpatadu SL, Wong DW, Parhar IS

Neuroscience, 2012 Aug 30;218:56-64.
PMID: 22626647 DOI: 10.1016/j.neuroscience.2012.05.023

Synthetic glucocorticoid (dexamethasone; DEX) treatment during the neonatal stage is known to affect reproductive activity. However, it is still unknown whether neonatal stress activates gonadotropin-inhibitory hormone (GnIH) synthesizing cells in the dorsomedial hypothalamus (DMH), which could have pronounced suppressive action on gonadotropin-releasing hormone (GnRH) neurons, leading to delayed pubertal onset. This study was designed to determine the effect of neonatal DEX (1.0mg/kg) exposure on reproductive maturation. Therefore, GnRH, GnIH and GnIH receptors, G-protein coupled receptors (GPR) 147 and GPR74 mRNA levels were measured using quantitative real-time PCR in female mice at postnatal (P) days 21, 30 and in estrus stage mice, aged between P45-50. DEX-treated females of P45-50 had delayed vaginal opening, and irregular estrus cycles and lower GnRH expression in the preoptic area (POA) when compared with age-matched controls. The expression levels of GPR147 and GPR74 mRNA in the POA increased significantly in DEX-treated female mice of P21 and P45-50 compared to controls. In addition, GPR147 and GPR74 mRNA expression was observed in laser captured single GnRH neurons in the POA. Although there was no difference in GnIH mRNA expression in the DMH, immunostained GnIH cell numbers in the DMH increased in DEX-treated females of P45-50 compared to controls. Taken together, the results show that the delayed pubertal onset could be due to the inhibition of GnRH gene expression after neonatal DEX treatment, which may be accounted for in part by the inhibitory signals from the up-regulated GnIH-GnIH receptor pathway to the POA.

Matched MeSH terms: Mice, Inbred C57BL
A comparison between the effects of three potential scar-reducing agents applied at a site of sciatic nerve repair

Ngeow WC, Atkins S, Morgan CR, Metcalfe AD, Boissonade FM, Loescher AR, et al.

Neuroscience, 2011 May 5;181:271-7.
PMID: 21377512 DOI: 10.1016/j.neuroscience.2011.02.054

We have investigated the effect of three potential scar-reducing agents applied at a sciatic nerve repair site in C57-black-6 mice. Under anaesthesia the nerve was transected, repaired using four epineurial sutures, and 100 μl of either triamcinolone acetonide (1 mg/100 μl), an interleukin-10 peptide fragment (125 ng/100 μl or 500 ng/100 μl) or mannose-6-phosphate (M6P, 200 mM or 600 mM) was injected into and around the nerve. After 6 weeks the extent of regeneration was assessed electrophysiologically by determining the ratio of the compound action potential (CAP) modulus evoked by electrical stimulation of the nerve 2 mm distal or proximal to the repair site. The conduction velocity of the fastest components in the CAP was also calculated. The percentage area of collagen staining (PAS) at the repair site was analysed using Picrosirius Red and image analysis. Comparisons were made with a placebo group (100 μl of phosphate buffered saline) and sham-operated controls. The median CAP modulus ratio in the 600 mM M6P group was 0.44, which was significantly higher than in the placebo group (0.24, P=0.012: Kruskal-Wallis test). Conduction velocities were also faster in the 600 mM M6P group (median 30 m s(-1)) than in the placebo group (median 27.8 m s(-1); P=0.0197: Kruskal-Wallis test). None of the other treated groups were significantly different from the placebo, and all had significantly lower CAP ratios than the sham controls (P<0.05). All repair groups had a significantly higher PAS for collagen than sham controls. We conclude that the administration of 600 mM mannose-6-phosphate to a nerve repair site enhances axonal regeneration.

Matched MeSH terms: Mice, Inbred C57BL
Citalopram (antidepressant) administration causes sexual dysfunction in male mice through RF-amide related peptide in the dorsomedial hypothalamus

Soga T, Wong DW, Clarke IJ, Parhar IS

Neuropharmacology, 2010 Jul-Aug;59(1-2):77-85.
PMID: 20381503 DOI: 10.1016/j.neuropharm.2010.03.018

Citalopram is the most potent selective serotonin reuptake inhibitor (SSRI) which is used as an antidepressant but causes sexual dysfunction. Whether citalopram induced sexual dysfunction is a result of gonadotropin-releasing hormone (GnRH), kisspeptin or RF-amide related peptide (RFRP) alteration is unknown. In this study, we tested mice for sexual behavior after vehicle (0.9% NaCl) and citalopram treatment (5 mg/kg) daily for 1 day (acute) and 21 or 28 days (chronic). Effects of acute and chronic treatments on neuronal numbers and mRNA expression of GnRH, kisspeptin and RFRP were measured. In addition, RFRP fiber projections to preoptic (POA)-GnRH neurons were analyzed using double-label immunohistochemistry. The expression of 14 different serotonin receptor types mRNA was examined in immunostained laser dissected single RFRP neurons in the dorsomedial hypothalamus (DMH), however only 11 receptors types were identified. Acute citalopram treatment did not affect sexual behavior, whereas, the total duration of intromission was reduced with chronic treatment. There was no effect in the expression of kisspeptin (neuronal numbers and mRNA) in the anteroventral periventricular nucleus and the arcuate nucleus and expression of GnRH (neuronal numbers and mRNA) in the POA after citalopram treatment. However, RFRP neuronal numbers in the DMH and fiber projections to the POA were significantly increased after chronic citalopram treatment, which suggests citalopram induced inhibition of sexual behavior involves the modulation of RFRP through serotonin receptors in the DMH.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Genetic Differences in the Immediate Transcriptome Response to Stress Predict Risk-Related Brain Function and Psychiatric Disorders

Arloth J, Bogdan R, Weber P, Frishman G, Menke A, Wagner KV, et al.

Neuron, 2015 Jun 03;86(5):1189-202.
PMID: 26050039 DOI: 10.1016/j.neuron.2015.05.034

Depression risk is exacerbated by genetic factors and stress exposure; however, the biological mechanisms through which these factors interact to confer depression risk are poorly understood. One putative biological mechanism implicates variability in the ability of cortisol, released in response to stress, to trigger a cascade of adaptive genomic and non-genomic processes through glucocorticoid receptor (GR) activation. Here, we demonstrate that common genetic variants in long-range enhancer elements modulate the immediate transcriptional response to GR activation in human blood cells. These functional genetic variants increase risk for depression and co-heritable psychiatric disorders. Moreover, these risk variants are associated with inappropriate amygdala reactivity, a transdiagnostic psychiatric endophenotype and an important stress hormone response trigger. Network modeling and animal experiments suggest that these genetic differences in GR-induced transcriptional activation may mediate the risk for depression and other psychiatric disorders by altering a network of functionally related stress-sensitive genes in blood and brain.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext A mouse model of weight-drop closed head injury: emphasis on cognitive and neurological deficiency

Khalin I, Jamari NL, Razak NB, Hasain ZB, Nor MA, Zainudin MH, et al.

Neural Regen Res, 2016 Apr;11(4):630-5.
PMID: 27212925 DOI: 10.4103/1673-5374.180749

Traumatic brain injury (TBI) is a leading cause of death and disability in individuals worldwide. Producing a clinically relevant TBI model in small-sized animals remains fairly challenging. For good screening of potential therapeutics, which are effective in the treatment of TBI, animal models of TBI should be established and standardized. In this study, we established mouse models of closed head injury using the Shohami weight-drop method with some modifications concerning cognitive deficiency assessment and provided a detailed description of the severe TBI animal model. We found that 250 g falling weight from 2 cm height produced severe closed head injury in C57BL/6 male mice. Cognitive disorders in mice with severe closed head injury could be detected using passive avoidance test on day 7 after injury. Findings from this study indicate that weight-drop injury animal models are suitable for further screening of brain neuroprotectants and potentially are similar to those seen in human TBI.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext A plasmid-encoded peptide from Staphylococcus aureus induces anti-myeloperoxidase nephritogenic autoimmunity

Ooi JD, Jiang JH, Eggenhuizen PJ, Chua LL, van Timmeren M, Loh KL, et al.

Nat Commun, 2019 07 29;10(1):3392.
PMID: 31358739 DOI: 10.1038/s41467-019-11255-0

Autoreactivity to myeloperoxidase (MPO) causes anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), with rapidly progressive glomerulonephritis. Here, we show that a Staphylococcus aureus peptide, homologous to an immunodominant MPO T-cell epitope (MPO409-428), can induce anti-MPO autoimmunity. The peptide (6PGD391-410) is part of a plasmid-encoded 6-phosphogluconate dehydrogenase found in some S. aureus strains. It induces anti-MPO T-cell autoimmunity and MPO-ANCA in mice, whereas related sequences do not. Mice immunized with 6PGD391-410, or with S. aureus containing a plasmid expressing 6PGD391-410, develop glomerulonephritis when MPO is deposited in glomeruli. The peptide induces anti-MPO autoreactivity in the context of three MHC class II allomorphs. Furthermore, we show that 6PGD391-410 is immunogenic in humans, as healthy human and AAV patient sera contain anti-6PGD and anti-6PGD391-410 antibodies. Therefore, our results support the idea that bacterial plasmids might have a function in autoimmune disease.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Basal lamina remodeling at the skeletal muscle stem cell niche mediates stem cell self-renewal

Rayagiri SS, Ranaldi D, Raven A, Mohamad Azhar NIF, Lefebvre O, Zammit PS, et al.

Nat Commun, 2018 03 14;9(1):1075.
PMID: 29540680 DOI: 10.1038/s41467-018-03425-3

A central question in stem cell biology is the relationship between stem cells and their niche. Although previous reports have uncovered how signaling molecules released by niche cells support stem cell function, the role of the extra-cellular matrix (ECM) within the niche is unclear. Here, we show that upon activation, skeletal muscle stem cells (satellite cells) induce local remodeling of the ECM and the deposition of laminin-α1 and laminin-α5 into the basal lamina of the satellite cell niche. Genetic ablation of laminin-α1, disruption of integrin-α6 signaling or blocking matrix metalloproteinase activity impairs satellite cell expansion and self-renewal. Collectively, our findings establish that remodeling of the ECM is an integral process of stem cell activity to support propagation and self-renewal, and may explain the effect laminin-α1-containing supports have on embryonic and adult stem cells, as well as the regenerative activity of exogenous laminin-111 therapy.

Matched MeSH terms: Mice, Inbred C57BL

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