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Comparative evaluation of the degree of pegylation of poly(lactic-co-glycolic acid) nanoparticles in enhancing central nervous system delivery of loperamide

Kirby BP, Pabari R, Chen CN, Al Baharna M, Walsh J, Ramtoola Z

J Pharm Pharmacol, 2013 Oct;65(10):1473-81.
PMID: 24028614 DOI: 10.1111/jphp.12125

In this study, we examined the relative cellular uptake of nanoparticles (NPs) formulated using poly(lactic-co-glycolic acid) (PLGA) polymers with increasing degree of pegylation (PLGA-PEG) and their potential to deliver loperamide to the brain of a mouse.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext DNA Vaccines Targeting Novel Cancer-Associated Antigens Frequently Expressed in Head and Neck Cancer Enhance the Efficacy of Checkpoint Inhibitor

Wang C, Zainal NS, Chai SJ, Dickie J, Gan CP, Zulaziz N, et al.

Front Immunol, 2021;12:763086.
PMID: 34733290 DOI: 10.3389/fimmu.2021.763086

HPV-independent head and neck squamous cell carcinoma (HNSCC) is a common cancer globally. The overall response rate to anti-PD1 checkpoint inhibitors (CPIs) in HNSCC is ~16%. One major factor influencing the effectiveness of CPI is the level of tumor infiltrating T cells (TILs). Converting TILlow tumors to TILhigh tumors is thus critical to improve clinical outcome. Here we describe a novel DNA vaccines to facilitate the T-cell infiltration and control tumor growth. We evaluated the expression of target antigens and their respective immunogenicity in HNSCC patients. The efficacy of DNA vaccines targeting two novel antigens were evaluated with or without CPI using a syngeneic model. Most HNSCC patients (43/44) co-expressed MAGED4B and FJX1 and their respective tetramer-specific T cells were in the range of 0.06-0.12%. In a preclinical model, antigen-specific T cells were induced by DNA vaccines and increased T cell infiltration into the tumor, but not MDSC or regulatory T cells. The vaccines inhibited tumor growth and improved the outcome alone and upon combination with anti-PD1 and resulted in tumor clearance in approximately 75% of mice. Pre-existence of MAGED4B and FJX1-reactive T cells in HNSCC patients suggests that these widely expressed antigens are highly immunogenic and could be further expanded by vaccination. The DNA vaccines targeting these antigens induced robust T cell responses and with the anti-PD1 antibody conferring excellent tumor control. This opens up an opportunity for combination immunotherapy that might benefit a wider population of HNSCC patients in an antigen-specific manner.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Evaluation of locomotor function and microscopic structure of the spinal cord in a mouse model of experimental autoimmune encephalomyelitis following treatment with syngeneic mesenchymal stem cells

Mitra NK, Bindal U, Eng Hwa W, Chua CL, Tan CY

Int J Clin Exp Pathol, 2015;8(10):12041-52.
PMID: 26722389

Out of the minor myelin proteins, most significant one is myelin oligodendrocyte glycoprotein (MOG). Mesenchymal stem cells (MSCs) have proven immunoregulatory capacity. The objective of this study was to investigate the effects of syngeneic MSCs on mouse model of experimental autoimmune encephalomyelitis (EAE) through observation of locomotion by footprint analysis, histological analysis of spinal cord and estimation IL-17. C57BL/6 mice (10 weeks, n = 16) were immunized with 300 µg of MOG35-55 and 200 µL of complete Freund's adjuvant (CFA) to produce EAE model. Sham-treated control (n = 8) were injected with CFA. Half of immunized mice were given 100 µL of PBS (n = 8) and next half (n = 8) received 1 × 10(5) MSCs on day 11 through the tail veins. Clinical scoring showed development of EAE (loss of tonicity of tail and weakness of hind limb) on day 10. Following MSC treatment, clinical scores and hindlimb stride length showed significant improvement on day 15 onwards, compared to day 10 (P < 0.05). Under LFB staining, while PBS-treated group of EAE mice showed pale and degenerated axons in anterolateral white column of lumbar spinal cord, MSC-treated group showed numerous normal-looking axons. H&E staining showed normal axons in anterolateral white column and reduction of macrophages in MSC-treated EAE mice group. A lower level of IL-17 was observed in MSC treated EAE mice, compared to PBS-treated EAE mice. Our results suggest that Intravenous MSC has the potential to improve the locomotion and regeneration of axons in spinal cord in MOG-induced EAE model.

Matched MeSH terms: Mice, Inbred C57BL
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
Clinacanthus nutans aqueous leaves extract exerts anti-allergic activity in preclinical anaphylactic models via alternative IgG pathway

Kow ASF, Khoo LW, Tan JW, Abas F, Lee MT, Israf DA, et al.

J Ethnopharmacol, 2023 Mar 01;303:116003.
PMID: 36464074 DOI: 10.1016/j.jep.2022.116003

ETHNOPHARMACOLOGICAL RELEVANCE: Allergy is mediated by the crosslinking of immunoglobulins (Ig) -E or -G to their respective receptors, which degranulates mast cells, macrophages, basophils, or neutrophils, releasing allergy-causing mediators. The removal of these mediators such as histamine, platelet-activating factor (PAF) and interleukins (ILs) released by effector cells will alleviate allergy. Clinacanthus nutans (C. nutans), an herbal plant in Southeast Asia, is used traditionally to treat skin rash, an allergic symptom. Previously, we have reported that C. nutans aqueous leaves extract (CNAE) was able to suppress the release of β-hexosaminidase and histamine but not interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-α) in the IgE-induced mast cell degranulation model at 5 mg/mL and above. We also found that CNAE could protect rats against ovalbumin-challenged active systemic anaphylaxis (OVA-ASA) through the downregulation and upregulation of certain metabolites using proton nuclear magnetic resonance (1H-NMR) metabolomics approach.
AIM OF THE STUDY: As allergy could be mediated by both IgE and IgG, we further evaluated the anti-allergy potential of CNAE in both in vitro model of IgG-induced macrophage activation and in vivo anaphylaxis models to further dissect the mechanism of action underlying the anti-allergic properties of CNAE.
MATERIAL & METHODS: The anti-allergy potential of CNAE was evaluated in in vivo anaphylaxis models of ovalbumin-challenged active systemic anaphylaxis (OVA-ASA) and IgE-challenged passive systemic anaphylaxis (PSA) using Sprague Dawley rats as well as IgG-challenged passive systemic anaphylaxis (IgG-PSA) using C57BL/6 mice. Meanwhile, in vitro model of IgG-induced macrophage activation model was performed using IC-21 macrophages. The release of soluble mediators from both IgE and IgG-mediated pathways were measured using enzyme-linked immunosorbent assay (ELISA). The signaling molecules targeted by CNAE were identified by performing Western blot.
RESULTS: IgG, platelet-activating factor (PAF) and IL-6 was suppressed by CNAE in OVA-ASA, but not IgE. In addition, CNAE significantly suppressed PAF and IL-6 in IgG-PSA but did not suppress histamine, IL-4 and leukotrienes C4 (LTC4) in IgE-PSA. CNAE also inhibited IL-6 and TNF-α by inhibiting the phosphorylation of ERK1/2 in the IgG-induced macrophage activation model.
CONCLUSION: Overall, our findings supported that CNAE exerts its anti-allergic properties by suppressing the IgG pathway and its mediators by inhibiting ERK1/2 phosphorylation, thus providing scientific evidence supporting its traditional use in managing allergy.

Matched MeSH terms: Mice, Inbred C57BL
Mesenchymal stem cells facilitate cardiac differentiation in Sox2-expressing cardiac C-kit cells in coculture

Leong YY, Ng WH, Umar Fuaad MZ, Ng CT, Ramasamy R, Lim V, et al.

J Cell Biochem, 2019 06;120(6):9104-9116.
PMID: 30548289 DOI: 10.1002/jcb.28186

Stem cell therapy offers hope to reconstitute injured myocardium and salvage heart from failing. A recent approach using combinations of derived Cardiac-derived c-kit expressing cells (CCs) and mesenchymal stem cells (MSCs) in transplantation improved infarcted hearts with a greater functional outcome, but the effects of MSCs on CCs remain to be elucidated. We used a novel two-step protocol to clonogenically amplify colony forming c-kit expressing cells from 4- to 6-week-old C57BL/6N mice. This method yielded highly proliferative and clonogenic CCs with an average population doubling time of 17.2 ± 0.2, of which 80% were at the G1 phase. We identified two distinctly different CC populations based on its Sox2 expression, which was found to inversely related to their nkx2.5 and gata4 expression. To study CCs after MSC coculture, we developed micron-sized particles of iron oxide-based magnetic reisolation method to separate CCs from MSCs for subsequent analysis. Through validation using the sex and species mismatch CC-MSC coculture method, we confirmed that the purity of the reisolated cells was greater than 85%. In coculture experiment, we found that MSCs prominently enhanced Ctni and Mef2c expressions in Sox2 pos CCs after the induction of cardiac differentiation, and the level was higher than that of conditioned medium Sox2 pos CCs. However, these effects were not found in Sox2 neg CCs. Immunofluorescence labeling confirmed the presence of cardiac-like cells within Sox2 pos CCs after differentiation, identified by its cardiac troponin I and α-sarcomeric actinin expressions. In conclusion, this study shows that MSCs enhance CC differentiation toward cardiac myocytes. This enhancement is dependent on CC stemness state, which is determined by Sox2 expression.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Mechanisms underpinning the permanent muscle damage induced by snake venom metalloprotease

Williams HF, Mellows BA, Mitchell R, Sfyri P, Layfield HJ, Salamah M, et al.

PLoS Negl Trop Dis, 2019 Jan;13(1):e0007041.
PMID: 30695027 DOI: 10.1371/journal.pntd.0007041

Snakebite is a major neglected tropical health issue that affects over 5 million people worldwide resulting in around 1.8 million envenomations and 100,000 deaths each year. Snakebite envenomation also causes innumerable morbidities, specifically loss of limbs as a result of excessive tissue/muscle damage. Snake venom metalloproteases (SVMPs) are a predominant component of viper venoms, and are involved in the degradation of basement membrane proteins (particularly collagen) surrounding the tissues around the bite site. Although their collagenolytic properties have been established, the molecular mechanisms through which SVMPs induce permanent muscle damage are poorly understood. Here, we demonstrate the purification and characterisation of an SVMP from a viper (Crotalus atrox) venom. Mass spectrometry analysis confirmed that this protein is most likely to be a group III metalloprotease (showing high similarity to VAP2A) and has been referred to as CAMP (Crotalus atrox metalloprotease). CAMP displays both collagenolytic and fibrinogenolytic activities and inhibits CRP-XL-induced platelet aggregation. To determine its effects on muscle damage, CAMP was administered into the tibialis anterior muscle of mice and its actions were compared with cardiotoxin I (a three-finger toxin) from an elapid snake (Naja pallida) venom. Extensive immunohistochemistry analyses revealed that CAMP significantly damages skeletal muscles by attacking the collagen scaffold and other important basement membrane proteins, and prevents their regeneration through disrupting the functions of satellite cells. In contrast, cardiotoxin I destroys skeletal muscle by damaging the plasma membrane, but does not impact regeneration due to its inability to affect the extracellular matrix. Overall, this study provides novel insights into the mechanisms through which SVMPs induce permanent muscle damage.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext The formyl peptide fMLF primes platelet activation and augments thrombus formation

Salamah MF, Ravishankar D, Vaiyapuri R, Moraes LA, Patel K, Perretti M, et al.

J Thromb Haemost, 2019 Jul;17(7):1120-1133.
PMID: 31033193 DOI: 10.1111/jth.14466

Essentials The role of formyl peptide receptor 1 (FPR1) and its ligand, fMLF, in the regulation of platelet function, hemostasis, and thrombosis is largely unknown. Fpr1-deficient mice and selective inhibitors for FPR1 were used to investigate the function of fMLF and FPR1 in platelets. N-formyl-methionyl-leucyl-phenylalanine primes platelet activation and augments thrombus formation, mainly through FPR1 in platelets. Formyl peptide receptor 1 plays a pivotal role in the regulation of platelet function.
BACKGROUND: Formyl peptide receptors (FPRs) play pivotal roles in the regulation of innate immunity and host defense. The FPRs include three family members: FPR1, FPR2/ALX, and FPR3. The activation of FPR1 by its high-affinity ligand, N-formyl-methionyl-leucyl-phenylalanine (fMLF) (a bacterial chemoattractant peptide), triggers intracellular signaling in immune cells such as neutrophils and exacerbates inflammatory responses to accelerate the clearance of microbial infection. Notably, fMLF has been demonstrated to induce intracellular calcium mobilization and chemotaxis in platelets that are known to play significant roles in the regulation of innate immunity and inflammatory responses. Despite a plethora of research focused on the roles of FPR1 and its ligands such as fMLF on the modulation of immune responses, their impact on the regulation of hemostasis and thrombosis remains unexplored.
OBJECTIVE: To determine the effects of fMLF on the modulation of platelet reactivity, hemostasis, and thrombus formation.
METHODS: Selective inhibitors for FPR1 and Fpr1-deficient mice were used to determine the effects of fMLF and FPR1 on platelets using various platelet functional assays.
RESULTS: N-formyl-methionyl-leucyl-phenylalanine primes platelet activation through inducing distinctive functions and enhances thrombus formation under arterial flow conditions. Moreover, FPR1 regulates normal platelet function as its deficiency in mouse or blockade in human platelets using a pharmacological inhibitor resulted in diminished agonist-induced platelet activation.
CONCLUSION: Since FPR1 plays critical roles in numerous disease conditions, its influence on the modulation of platelet activation and thrombus formation may provide insights into the mechanisms that control platelet-mediated complications under diverse pathological settings.

Matched MeSH terms: Mice, Inbred C57BL
Identification of the genomic mutation in Epha4(rb-2J/rb-2J) mice

Mohd-Zin SW, Abdullah NL, Abdullah A, Greene ND, Cheah PS, Ling KH, et al.

Genome, 2016 Jul;59(7):439-48.
PMID: 27373307 DOI: 10.1139/gen-2015-0142

The EphA4 receptor tyrosine kinase is involved in numerous cell-signalling activities during embryonic development. EphA4 has the ability to bind to both types of ephrin ligands, the ephrinAs and ephrinBs. The C57BL/6J-Epha4rb-2J/GrsrJ strain, denoted Epha4(rb-2J/rb-2J), is a spontaneous mouse mutant that arose at The Jackson Laboratory. These mutants exhibited a synchronous hind limb locomotion defect or "hopping gait" phenotype, which is also characteristic of EphA4 null mice. Genetic complementation experiments suggested that Epha4(rb-2J) corresponds to an allele of EphA4, but details of the genomic defect in this mouse mutant are currently unavailable. We found a single base-pair deletion in exon 9 resulting in a frame shift mutation that subsequently resulted in a premature stop codon. Analysis of the predicted structure of the truncated protein suggests that both the kinase and sterile α motif (SAM) domains are absent. Definitive determination of genotype is needed for experimental studies of mice carrying the Epha4(rb-2J) allele, and we have also developed a method to ease detection of the mutation through RFLP. Eph-ephrin family members are reportedly expressed as numerous isoforms. Hence, delineation of the specific mutation in EphA4 in this strain is important for further functional studies, such as protein-protein interactions, immunostaining and gene compensatory studies, investigating the mechanism underlying the effects of altered function of Eph family of receptor tyrosine kinases on phenotype.

Matched MeSH terms: Mice, Inbred C57BL
Aromatic and Aliphatic Apiuronides from the Bark of Cinnamomum cassia

Chang SW, Lee JS, Lee JH, Kim JY, Hong J, Kim SK, et al.

J Nat Prod, 2021 Mar 26;84(3):553-561.
PMID: 33684292 DOI: 10.1021/acs.jnatprod.0c01062

Cinnamomum cassia Presl (Cinnamon) has been widely cultivated in the tropical or subtropical areas, such as Yunnan, Fujian, Guandong, and Hainan in China, as well as India, Vietnam, Thailand, and Malaysia. Four new glycosides bearing apiuronic acid (1, 4, 6, and 7) and their sodium or potassium salts (2, 3, and 5), together with 31 known compounds, were isolated from a hot water extract of the bark of C. cassia via repeated chromatography. The structures of the new compounds (1-7) were determined by NMR, IR, MS, and ICP-AES data and by acid hydrolysis and sugar analysis. This is the first report of the presence of apiuronic acid glycosides. Some of the isolates were evaluated for their analgesic effects on a neuropathic pain animal model induced by paclitaxel. Cinnzeylanol (8), cinnacaside (9), kelampayoside A (10), and syringaresinol (11) showed analgesic effects against paclitaxel-induced cold allodynia.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Keyhole limpet hemocyanin augmented the killing activity, cytokine production and proliferation of NK cells, and inhibited the proliferation of Meth A sarcoma cells in vitro

Sarker MM, Zhong M

Indian J Pharmacol, 2014 Jan-Feb;46(1):40-5.
PMID: 24550583 DOI: 10.4103/0253-7613.125164

Keyhole limpet hemocyanin (KLH) is a popular tumor vaccine carrier protein and an immunostimulant. The present study aimed to investigate the immunoregulatory activity of KLH on cytotoxicity, cytokines production, and proliferation of natural killer (NK) cells. Moreover, antiproliferative activity of KLH on Meth A sarcoma cells was studied.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Intact urothelial barrier function in a mouse model of ketamine-induced voiding dysfunction

Rajandram R, Ong TA, Razack AH, MacIver B, Zeidel M, Yu W

Am J Physiol Renal Physiol, 2016 05 01;310(9):F885-94.
PMID: 26911853 DOI: 10.1152/ajprenal.00483.2015

Ketamine is a popular choice for young drug abusers. Ketamine abuse causes lower urinary tract symptoms, with the underlying pathophysiology poorly understood. Disruption of urothelial barrier function has been hypothesized to be a major mechanism for ketamine cystitis, yet the direct evidence of impaired urothelial barrier function is still lacking. To address this question, 8-wk-old female C57BL/6J mice were injected intraperitoneally with 30 mg·kg(-1)·day(-1) ketamine for 12 wk to induce ketamine cystitis. A spontaneous voiding spot assay showed that ketamine-treated mice had increased primary voiding spot numbers and smaller primary voiding spot sizes than control mice (P < 0.05), indicating a contracted bladder and bladder overactivity. Consistently, significantly increased voiding frequency was observed in ketamine-treated mice on cystometrograms. These functional experiments indicate that ketamine induces voiding dysfunction in mice. Surprisingly, urothelial permeability in ketamine-treated mice was not changed when measured using an Ussing chamber system with isotopic urea and water. Mouse urothelial structure was also not altered, and intact umbrella cell structure was observed by both transmission and scanning electron microscopy. Furthermore, immunostaining and confocal microscopy confirmed the presence of a well-defined distribution of zonula occuldens-1 in tight junctions and uroplakin in umbrella cells. In conclusion, these data indicate that ketamine injection induces voiding dysfunction in mice but does not necessarily disrupt mouse bladder barrier function. Disruption of urothelial barrier function may not be the major mechanism in ketamine cystitis.

Matched MeSH terms: Mice, Inbred C57BL
Astragaloside I from Astragalus Attenuates Diabetic Kidney Disease by Regulating HDAC3/Klotho/TGF-β1 Loop

Zhang X, Wang J, Xiang S, Zhao L, Lv M, Duan Y, et al.

Am J Chin Med, 2024;52(6):1795-1817.
PMID: 39347955 DOI: 10.1142/S0192415X24500708

Diabetic kidney disease (DKD) has become the primary cause of end-stage renal disease (ESRD), causing an urgent need for preventive strategies for DKD. Astragaloside I (ASI), a bioactive saponin extracted from Astragalus membranaceus (Fisch.) Bunge has been demonstrated to possess a variety of biological activities. This study investigates the therapeutic potential of ASI in DKD and the underlying molecular mechanism using db/db mice in vivo and high glucose (HG)-induced SV40-MES-13 cells in vitro. The results indicated that ASI significantly ameliorated renal dysfunction and mitigated the pathological alterations in the renal tissues of db/db mice. Moreover, ASI was found to reduce the levels of renal fibrosis makers and suppress the activation of TGF-β1/Smad2/3 pathway in both db/db mice and HG-induced SV40-MES-13 cells. Furthermore, ASI downregulated HDAC3 expression, upregulated Klotho expression, and enhanced Klotho release. ASI is directly bound to HDAC3, and the beneficial effects of ASI on Klotho/TGF-β1/Smad2/3-mediciated renal fibrosis in DKD were reversed by the HDAC3 agonist ITSA-1. In conclusion, ASI attenuates renal fibrosis in DKD, and may act through concurrently inhibiting HDAC3 and TGF-β1, thereby regulating HDAC3-mediciated Klotho/TGF-β1/Smad2/3 pathway.

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
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
Fulltext Helicobacter pylori infection can affect energy modulating hormones and body weight in germ free mice

Khosravi Y, Seow SW, Amoyo AA, Chiow KH, Tan TL, Wong WY, et al.

Sci Rep, 2015;5:8731.
PMID: 25736205 DOI: 10.1038/srep08731

Helicobacter pylori, is an invariably commensal resident of the gut microbiome associated with gastric ulcer in adults. In addition, these patients also suffered from a low grade inflammation that activates the immune system and thus increased shunting of energy to host defense mechanisms. To assess whether a H. pylori infection could affect growth in early life, we determined the expression levels of selected metabolic gut hormones in germ free (GF) and specific pathogen-free (SPF) mice with and without the presence of H. pylori. Despite H. pylori-infected (SPFH) mice display alteration in host metabolism (elevated levels of leptin, insulin and peptide YY) compared to non-infected SPF mice, their growth curves remained the same. SPFH mice also displayed increased level of eotaxin-1. Interestingly, GF mice infected with H. pylori (GFH) also displayed increased levels of ghrelin and PYY. However, in contrast to SPFH mice, GFH showed reduced weight gain and malnutrition. These preliminary findings show that exposure to H. pylori alters host metabolism early in life; but the commensal microbiota in SPF mice can attenuate the growth retarding effect from H. pylori observed in GF mice. Further investigations of possible additional side effects of H. pylori are highly warranted.

Matched MeSH terms: Mice, Inbred C57BL
Fulltext Functional transcriptome analysis of the postnatal brain of the Ts1Cje mouse model for Down syndrome reveals global disruption of interferon-related molecular networks

Ling KH, Hewitt CA, Tan KL, Cheah PS, Vidyadaran S, Lai MI, et al.

BMC Genomics, 2014;15:624.
PMID: 25052193 DOI: 10.1186/1471-2164-15-624

The Ts1Cje mouse model of Down syndrome (DS) has partial triplication of mouse chromosome 16 (MMU16), which is partially homologous to human chromosome 21. These mice develop various neuropathological features identified in DS individuals. We analysed the effect of partial triplication of the MMU16 segment on global gene expression in the cerebral cortex, cerebellum and hippocampus of Ts1Cje mice at 4 time-points: postnatal day (P)1, P15, P30 and P84.

Matched MeSH terms: Mice, Inbred C57BL
Dietary repletion with ω3 fatty acid or with COX inhibition reverses cognitive effects in F3 ω3 fatty-acid-deficient mice

Hafandi A, Begg DP, Premaratna SD, Sinclair AJ, Jois M, Weisinger RS

Comp. Med., 2014 Apr;64(2):106-9.
PMID: 24674584

Dietary deficiency of ω3 fatty acid during development leads to impaired cognitive function. However, the effects of multiple generations of ω3 fatty-acid deficiency on cognitive impairment remain unclear. In addition, we sought to test the hypothesis that the cognitive impairments of ω3 fatty-acid-deficient mice are mediated through the arachidonic acid-cyclooxygenase (COX) pathway. To address these issues, C57BL/6J mice were bred for 3 generations and fed diets either deficient (DEF) or sufficient (SUF) in ω3 fatty acids. At postnatal day 21, the F3 offspring remained on the dam's diet or were switched to the opposite diet, creating 4 groups. In addition, 2 groups that remained on the dam's diet were treated with a COX inhibitor. At 19 wk of age, spatial-recognition memory was tested on a Y-maze. Results showed that 16 wk of SUF diet reversed the cognitive impairment of F3 DEF mice. However, 16 wk of ω3 fatty-acid-deficient diet impaired the cognitive performance of the F3 SUF mice, which did not differ from that of the F3 DEF mice. These findings suggest that the cognitive deficits after multigenerational maintenance on ω3 fatty-acid-deficient diet are not any greater than are those after deficiency during a single generation. In addition, treatment with a COX inhibitor prevented spatial-recognition deficits in F3 DEF mice. Therefore, cognitive impairment due to dietary ω3 fatty-acid deficiency appears to be mediated by the arachidonic acid-COX pathway and can be prevented by 16 wk of dietary repletion with ω3 fatty acids or COX inhibition.

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
Fulltext Triplex PCR using new primers for the detection of Toxoplasma gondii

Rahumatullah A, Khoo BY, Noordin R

Exp Parasitol, 2012 Jun;131(2):231-8.
PMID: 22561042 DOI: 10.1016/j.exppara.2012.04.009

Molecular methods are used increasingly for the detection of Toxoplasma gondii infection. This study developed a rapid, sensitive, and specific conventional triplex PCR for the detection of the B1 gene and ITS1 region of T. gondii using newly designed primers and an internal control based on the Vibrio cholerae HemM gene. The annealing temperature and concentrations of the primers, MgCl(2), and dNTPs were optimized. Two sets of primers (set 1 and 2) were tested, which contained different segments of the T. gondii B1 gene, 529 repeat region and ITS1 region. A series of sensitivity tests were performed using parasite DNA, whole parasites, and spiked human body fluids. Specificity tests were performed using DNA from common protozoa and bacteria. The newly developed assay based on set 2 primers was found to be specific and sensitive. The test was capable of detecting as little as 10 pg T. gondii DNA, 10(4) tachyzoites in spiked body fluids, and T. gondii DNA in the organ tissues of experimentally infected mice. The assay developed in this study will be useful for the laboratory detection of T. gondii infection.

Matched MeSH terms: Mice, Inbred C57BL

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