Behavioral Perturbation and Sleep in Healthy and Virus-Infected Inbred Mice

Murine gammaherpesvirus (MuGHV) is a natural pathogen of wild rodents that has been studied extensively in terms of host immune responses to herpesviruses during acute infection, latency, and reactivation from latency. Although herpesvirus infections in people can be associated with fatigue and excessive sleepiness during both acute and latent infection, MuGHV has not been assessed extensively as a model for studying the behavioral consequences of chronic latent herpesvirus infections. To assess MuGHV infection as a model for evaluating fatigue and assessing potential mechanisms that underlie the exacerbation of fatigue during chronic viral disease, we evaluated sleep, temperature, and activity after exposure of healthy and latently MuGHV-infected mice to sleep fragmentation and social interaction. Neither treatment nor infection significantly affected temperature. However, at some time points, latently infected mice that underwent sleep fragmentation had less locomotor activity and more slow-wave sleep than did mice exposed to social interaction. In addition, delta-wave amplitude during slow-wave sleep was lower in infected mice exposed to sleep fragmentation compared with uninfected mice exposed to the same treatment. Both reduced locomotor activity and increased time asleep could indicate fatigue in infected mice after sleep fragmentation; reduced delta-wave amplitude during slow-wave sleep indicates a light plane of sleep from which subjects would be aroused easily. Identifying the mechanisms that underlie sleep responses of mice with chronic latent MuGHV infection may increase our understanding of fatigue during infections and eventually contribute to improving the quality of life for people with chronic viral infections.Abbreviations: CFS, chronic fatigue syndrome; DWA, delta-wave amplitude; EBV, Epstein–Barr virus; MuGHV, murine γ-herpesvirus; REMS, rapid-eye-movement sleep; SF, sleep fragmentation; SI, social interaction; SWS, slow-wave sleepEpstein–Barr virus (EBV) is a ubiquitous human γ-herpesvirus that causes acute disease, establishes life-long latency and is associated with the common syndrome of infectious mononucleosis. Murine gammaherpesvirus (MuGHV) is a natural pathogen of wild rodents that provides an experimental animal model for studying the pathophysiology of an EBV-like gammaherpesvirus.^10,27 A comparison of MuGHV strain 68 (MuGHV68) infection in bank voles (a natural host) and laboratory mice (Mus musculus) using in vivo luciferase imaging and classic virologic methods showed that the 2 host species have quantitative differences in the magnitude of the infection yet exhibit comparable patterns of viral replication and sites of viral latency.¹² These findings support using MuGHV68 and Mus musculus for the study of gammaherpesvirus pathogenesis. Although MuGHV has been studied extensively with regard to host immune responses to herpesviruses during acute infection, latency, and reactivation from latency,^10,27 it has not been assessed extensively as a model for the study of the behavioral consequences of chronic latent herpesvirus infections.EBV infection in humans is often associated with fatigue and excessive sleepiness during both acute and latent phases of infection.^{1,16,19,38,43,44} Many people similarly experience fatigue in association with other chronic medical conditions that have either specific viral etiologies (for example, hepatitis C, HIV) or symptoms suggestive of viral infections (for example, chronic fatigue syndrome (CFS), fibromyalgia syndrome).^3,21,23 Acute viral infections, persistent viral infections, and reactivation of latent virus may trigger or exacerbate fatigue.^15,29,35 Furthermore, exacerbation of fatigue in response to various physiologic and psychologic challenges is prominent in many disease conditions associated with chronic fatigue. For example, exercise is reported to precipitate or exacerbate fatigue or malaise in persons with CFS,^2,26 and CFS both reduces activity and blunts the circadian rhythm of activity in patients.⁴² In addition, stressful life events are reported to precipitate CFS and to exacerbate fatigue in persons with CFS,^6,37and stress can be a factor in reactivation of latent EBV and other herpesviruses.¹⁵ Fatigue, like other so-called ‘sickness behaviors’ (for example, anorexia, anhedonia, reduced social interaction), has been linked causally to various cytokines that are facets of the immune response.⁷ Therefore, the host immune response to chronic infection or inflammation is likely to create a powerful and unrelenting stimulus for fatigue.Human fatigue can be viewed as continued performance of essential activities (for example, employment, care-giving) with curtailment of nonessential, voluntary, or recreational activities.³² Similarly, fatigue in mice can be defined operationally as a reduction in voluntary activity (that is, wheel running) as compared with essential activity (that is, locomotion in the cage to obtain food and water).^28,30,33 Problems with sleep can either reflect or contribute to fatigue. For example, excessive sleep may reflect fatigue associated with other causes, whereas poor sleep or inadequate amounts of sleep may cause fatigue.Mice inoculated with MuGHV develop changes in sleep and activity that may indicate fatigue. On days 7 through 11 after inoculation (that is, at times associated with the peak lytic infection and its resolution), infected mice show hypothermia, increased somnolence, and reduced running-wheel activity during the dark (active) phase of the diurnal cycle as well as reduced food intake and body weight.²⁸ These measures all return to normal during days 11 through 30 after inoculation, as the virus enters the latent phase.²⁸ After this time, these behavioral indicators of fatigue can again be elicited by challenging mice with LPS. In uninfected mice, LPS administration induces modest and relatively transient (that is, less than 18 h) hypothermia, reduced running-wheel activity, and alterations in sleep.²⁸ In contrast, mice with latent MuGHV infection develop prolonged hypothermia, hypoactivity, hypersomnolence, and fragmented sleep, all of which persist for as long as 5 d after LPS administration.²⁸ This duration is consistent with the time reported for viral reactivation from latency in MuGHV-infected mice treated with LPS.¹⁴ Therefore, as compared with uninfected mice, mice with latent infections appear to show a greater magnitude and duration of LPS-induced behavioral perturbations that may reflect fatigue, perhaps in association with virus reactivation.To further assess MuGHV infection as a model system for evaluation of fatigue and assessment of potential mechanisms that underlie exacerbation of fatigue during chronic viral disease, we extended our previous work^28,40 by evaluating sleep, temperature, and activity after exposure of uninfected and latently infected mice to sleep fragmentation (SF) and social interaction (SI), both of which are likely to create behavioral stress.     

Spontaneous Mutation in the Escherichia Coli Laci Gene

To gain more detailed insight into the nature and mechanisms of spontaneous mutations, we undertook a DNA sequence analysis of a large collection of spontaneous mutations in the N-terminal region of the Escherichia coli lacI gene. This region of circa 210 base pairs is the target for dominant lacI mutations (i-d) and is suitable for studies of mutational specificity since it contains a relatively high density of detectable mutable sites. Among 414 independent i-d mutants, 70.8% were base substitutions, 17.2% deletions, 7.7% additions and 4.3% single-base frameshifts. The base substitutions were both transitions (60%) and transversions (40%), the largest single group being G.C----A.T (47% of base substitutions). All four transversions were observed. Among the 71 deletions, a hotspot (37 mutants) was present: an 87-bp deletion presumably directed by an 8-bp repeated sequence at its endpoints. The remaining 34 deletions were distributed among 29 different mutations, either flanked (13/34) or not flanked (21/34) by repeated sequences. The 32 additions comprised 29 different events, with only two containing a direct repeat at the endpoints. The single-base frameshifts were the loss of a single base from either repeated (67%) or nonrepeated (33%) bases. A comparison with the spectrum obtained previously in strains defective in DNA mismatch correction (mutH, mutL, mutS strains) yielded information about the apparent efficiency of mismatch repair. The overall effect was 260-fold but varied substantially among different classes of mutations. An interesting asymmetry was uncovered for the two types of transitions, A.T----G.C and G.C----A.T being reduced by mismatch repair 1340- and 190-fold, respectively. Explanations for this asymmetry and its possible implications for the origins of spontaneous mutations are discussed.     

Susceptibility to Spontaneous Pneumonitis in an Inbred Strain of Beige and Satin Mice

Among mice of strain SB/Le, homozygous for the mutant genes beige (bg), satin (sa), and white-bellied agouti (A(w)), 70% developed progressive pneumonitis by 6 months of age. Among backcross offspring from an outcross to C57BL/6J-A(w-J), 49% of homozygous beige and 11% of nonbeige genotypes developed pneumonitis by 6 months of age. The evidence indicates that a specific action of the beige gene increases susceptibility to progressive pneumonitis. Lymphadenopathy, including reticulum cell neoplasms and atypical lymphoproliferative lesions, was observed in high incidence in sa+/sa bg males, suggesting a closer association with satin than with beige. Beige mice show giant lysosomal granules in the leukocytes and pigment dilution closely analogous to the Chediak-Higashi syndrome in man and similar disorders in mink and cattle. Strain SB/Le provides a convenient model in a laboratory animal for study of the increased susceptibility to infection analogous to that of the Chediak-Higashi syndrome.     

TW近交系小鼠的血液生化及毛色基因检测

目的建立野生来源TW（Tianjin wild,TW）近交系小鼠的体重和血液生化正常范围并检测其毛色基因纯合性。方法分别选用F23代TW近交系成年小鼠,进行毛色基因测试,并检测动物的体重及血液生化指标。结果 6周龄前,雌雄TW小鼠体重差异无统计学意义（P〈0.05）;6周龄后雄性TW小鼠体重明显高于同期雌性小鼠体重,差异具有统计学意义（P〈0.05）。血生化检测指标中,雌雄小鼠的总蛋白和甘油三酯均值不同,差异具有统计学意义（P〈0.05）,其他各项差异均无统计学意义（P〉0.05）,且与文献报道的其他品系结果不一致。毛色基因测试,F1代小鼠的毛色为白腹野生色,其基因型为AWAWBBccDD。结论 TW小鼠毛色基因已达纯合,且在一些指标上与通用实验小鼠品系不同,具有自身特点。     

Genetic Association between H-2 Gene and Testosterone Metabolism in Mice

SEVERAL characters involved in sexual dimorphism or male reproductive performance are influenced by genetic factors that are linked with the histocompatibility-2 (H-2) system of the mouse. These factors influence sperm cell production and function^1–4 interstrain differences in relative weights of vesicular gland and testis^4,5, immune response to the male-specific histocompatibility antigen^6,7 and an androgen-dependent allotypic serum protein designated Slp⁸. Our finding of an H-2 linked gene influencing the size of such male hormone-dependent organs, as is the vesicular gland and testis, suggested that the amount of testosterone in plasma may be influenced by an H-2 linked gene. Whereas the genetic control of some hormonally determined traits is considered to be polygenic^9,10, other data indicate some endocrine variation is due to allelic substitution at a single locus or very few loci^11–14. These genes in the mouse genome have not yet been located.     

KATNAL1 基因突变筛查及其与无精症的相关性分析

目的:探讨男性不育症患者Katnal15基因的一个突变位点与男性不育症的关系及意义。方法:运用聚合酶链反应(PCR)结合琼脂糖凝胶电泳和基因序列分析等方法,对77例原发性男性不育患者以及84名已生育的正常男性进行Katnal1基因筛查。结果:与精子形成的关键基因KATNAL1中1个致病突变位点A236G为的男性精子无力症Katnal1基因筛查的主要候选基因。结论:Katnal1基因蛋白质编码序列区A236G可能是特发性少精无精症的诱发因素之一。临床上对原发性不育患者进行A236G基因突变筛查是十分必要的。     

Metabolic and Phenotypic Differences between Mice Producing a Werner Syndrome Helicase Mutant Protein and Wrn Null Mice

Werner syndrome (WS) is a premature aging disorder caused by mutations in a RecQ-family DNA helicase, WRN. Mice lacking part of the helicase domain of the WRN orthologue exhibit many phenotypic features of WS, including metabolic abnormalities and a shorter mean life span. In contrast, mice lacking the entire Wrn protein (i.e. Wrn null mice) do not exhibit a premature aging phenotype. In this study, we used a targeted mass spectrometry-based metabolomic approach to identify serum metabolites that are differentially altered in young Wrn helicase mutant and Wrn null mice. An antibody-based quantification of 43 serum cytokines and markers of cardiovascular disease risk complemented this study. We found that Wrn helicase mutants exhibited elevated and decreased levels, respectively, of the anti-inflammatory cytokine IL-10 and the pro-inflammatory cytokine IL-18. Wrn helicase mutants also exhibited an increase in serum hydroxyproline and plasminogen activator inhibitor-1, markers of extracellular matrix remodeling of the vascular system and inflammation in aging. We also observed an abnormal increase in the ratio of very long chain to short chain lysophosphatidylcholines in the Wrn helicase mutants underlying a peroxisome perturbation in these mice. Remarkably, the Wrn mutant helicase protein was mislocalized to the endoplasmic reticulum and the peroxisomal fractions in liver tissues. Additional analyses with mouse embryonic fibroblasts indicated a severe defect of the autophagy flux in cells derived from Wrn helicase mutants compared to wild type and Wrn null animals. These results indicate that the deleterious effects of the helicase-deficient Wrn protein are mediated by the dysfunction of several cellular organelles.     

Characterization of a Spontaneous Novel Mutation in the NPC2 Gene in a Cat Affected by Niemann Pick Type C Disease

Niemann-Pick C disease (NPC) is an autosomal recessive lysosomal storage disorder characterized by accumulation of unesterified cholesterol and other lipids within the lysosomes due to mutation in NPC1 or NPC2 genes. A feline model of NPC carrying a mutation in NPC1 gene has been previously described. We have identified two kittens affected by NPC disease due to a mutation in NPC2 gene. They manifested with tremors at the age of 3 months, which progressed to dystonia and severe ataxia. At 6 months of age cat 2 was unable to stand without assistance and had bilaterally reduced menace response. It died at the age of 10 months. Post-mortem histological analysis of the brain showed the presence of neurons with cytoplasmic swelling and vacuoles, gliosis of the substantia nigra and degeneration of the white matter. Spheroids with accumulation of ubiquitinated aggregates were prominent in the cerebellar cortex. Purkinje cells were markedly reduced in number and they showed prominent intracytoplasmic storage. Scattered perivascular aggregates of lymphocytes and microglial cells proliferation were present in the thalamus and midbrain. Proliferation of Bergmann glia was also observed. In the liver, hepatocytes were swollen because of accumulation of small vacuoles and foamy Kupffer cells were also detected. Foamy macrophages were observed within the pulmonary interstitium and alveoli as well. At 9 months cat 1 was unable to walk, developed seizures and it was euthanized at 21 months. Filipin staining of cultured fibroblasts showed massive storage of unesterified cholesterol. Molecular analysis of NPC1 and NPC2 genes showed the presence of a homozygous intronic mutation (c.82+5G>A) in the NPC2 gene. The subsequent analysis of the mRNA showed that the mutation causes the retention of 105 bp in the mature mRNA, which leads to the in frame insertion of 35 amino acids between residues 28 and 29 of NPC2 protein (p.G28_S29ins35).     

Spontaneous Mutation Rates in Mammalian Cells: Effect of Differential Growth Rates and Phenotypic Lag

We calculated a spontaneous rate of 26-37 x 10(-6) mutations per cell division for L5178Y MOLY (mouse lymphoma) cells at the thymidine kinase locus (tk+/(-)----tk-/-) using a procedure that isolated and segregated cells during expression. This rate was 50 times higher than when cells expressed the mutant phenotype in suspension. The higher mutation rates obtained with the in situ procedure suggest that many of the mutants, whether expressed or unexpressed, grew more slowly than wild-type cells prior to selection with trifluorothymidine (TFT), implying that the slow growth phenotype is expressed earlier than the TFTr (TFT-resistant) phenotype. The loss of mutants was not restricted to cells forming small colonies; the mutation rate for cells forming large colonies was more than ten times higher using the in situ procedure. In this new procedure, the cells expressed spontaneous mutations while growing in semisolid medium for up to 3 days without TFT. Mutants were then selected in situ by adding an overlay of TFT and the visible colonies were analyzed after 11 days. Cells with spontaneous mutations at the tk locus required approximately 30 hr for the more rapidly expressing cells with new mutations to be detected. Most of the TFTr colonies selected after 60 hr of growth in semisolid medium represented independent mutations that had accumulated during the first 30 hr.(ABSTRACT TRUNCATED AT 250 WORDS)     

中国人扩张型心肌病与受磷蛋白基因关系的研究

受磷蛋白（phospholamban）是心肌收缩的一个重要调节因子,可抑制心肌肌浆网钙ATPase的活性、降低其对钙的亲和力。正常情况下,受磷蛋白可被不同的蛋白激酶磷酸化从而解除其肌浆网钙ATPase的抑制作用。国外两个DCM家系研究发现受磷蛋白基因突变与DCM的发生有关,研究目的旨在探讨中国人群心肌特异性受磷蛋白基因突变与特发性扩张型心肌病发病的关系。收集60例确诊的特发性扩张型心肌病患者临床资料,采集血样本并分离白细胞和提取基因组DNA。应用PCR扩增肌特异性受磷蛋白基因片段,经测序检测基因突变的存在。结果显示60例扩张型心肌病人受磷蛋白基因开放阅读框未发现突变,仅有两例患者出现阅读框3′部分非翻译区分别离终止密码153和173位单个碱基T的缺失。两例患者终止密码后非翻译区单个碱基T的缺失据分析并无实际意义。因此我们认为绝大部分中国人扩张型心肌病的发病可能与受磷蛋白基因突变无关。Abstract: Phospholamban (PLB) is a prominent regulator of myocardial contractility and a reversible inhibitor of the cardiac sarcoplasmic reticulum Ca2+ ATPase activity. In normal cardiac muscles, phospholamban can be phosphorylated at distinct sites by various protein kinases and release its inhibition to sarcoplasmic reticulum Ca2+ ATPase. The studies of pedigrees have shown dilated cardiomyopathy (DCM) is related with mutation of PLB. The aim of present study is to investigate the relationship between mutation of PLB gene and DCM. Sixty patients with idiotic DCM were enrolled in present study. The clinical data were collected, including clinical symptoms, ECG and echocardiography. Peripheral blood samples of all these subjects were collected to extract genome DNA. The fragments of PLB gene were amplified by PCR and PCR fragment sequencing was performed to study weather mutation of phospholamban gene exists. phospholamban gene did not show any mutation in these patients. Most Chinese DCM patients may not be related with mutation of PLB gene.     

Genotypic and Phenotypic Studies of Murine Intestinal Lactobacilli: Species Differences in Mice with and without Colitis

Lactobacilli represent components of the commensal mammalian gastrointestinal microbiota and are useful as probiotics, functional foods, and dairy products. This study includes systematic polyphasic analyses of murine intestinal Lactobacillus isolates and correlation of taxonomic findings with data from cytokine production assays. Lactobacilli were recovered from mice with microbiota-dependent colitis (interleukin-10 [IL-10]-deficient C57BL/6 mice) and from mice without colitis (Swiss Webster and inducible nitric oxide synthetase-deficient C57BL/6 mice). Polyphasic analyses were performed to elucidate taxonomic relationships among 88 reference and murine gastrointestinal lactobacilli. Genotypic tests included single-locus analyses (16S ribosomal DNA sequencing and 16S-23S rRNA intergenic spacer region PCR) and genomic DNA profiling (repetitive DNA element-based PCR), and phenotypic analyses encompassed more than 50 tests for carbohydrate utilization, enzyme production, and antimicrobial resistance. From 20 mice without colitis, six Lactobacillus species were recovered; the majority of the mice were colonized with L. reuteri or L. murinus (72% of isolates). In contrast, only, L. johnsonii was isolated from 14 IL-10-deficient mice. Using an in vitro assay, we screened murine isolates for their ability to inhibit tumor necrosis factor alpha (TNF-α) secretion by lipopolysaccharide-activated macrophages. Interestingly, a subpopulation of lactobacilli recovered from mice without colitis displayed TNF-α inhibitory properties, whereas none of the L. johnsonii isolates from IL-10-deficient mice exhibited this effect. We propose that differences among intestinal Lactobacillus populations in mammals, combined with host genetic susceptibilities, may account partly for variations in host mucosal responses.     

A Gain-Of-Function Mutation in the Plcg2 Gene Protects Mice from Helicobacter felis-Induced Gastric MALT Lymphoma

Gastric mucosa-associated lymphoid tissue (MALT) lymphomas develop from a chronic Helicobacter infection. Phospholipase C gamma 2 (PLCG2) is important for B-cell survival and proliferation. We used BALB/c mice with a gain-of-function mutation in the Plcg2 gene (Ali5) to analyze its role in the development of gastric MALT lymphoma. Heterozygous BALB/c Plcg2^Ali5/+ and wildtype (WT) mice were infected with Helicobacter felis (H. felis) and observed up to 16 months for development of gastric MALT lymphomas. In contrast to our initial hypothesis, Plcg2^Ali5/+ mice developed MALT lymphomas less frequently than their WT littermates after long-term infection of 16 months. Infected Plcg2^Ali5/+ mice showed downregulation of proinflammatory cytokines and decreased H. felis-specific IgG1 and IgG2a antibody responses. These results suggested a blunted immune response of Plcg2^Ali5/+ mice towards H. felis infection. Intriguingly, Plcg2^Ali5/+ mice harboured higher numbers of CD73 expressing regulatory T cells (Tregs), possibly responsible for impaired immune response towards Helicobacter infection. We suggest that Plcg2^Ali5/+ mice may be protected from developing gastric MALT lymphomas as a result of elevated Treg numbers, reduced response to H. felis and decrease of proinflammatory cytokines.     

Differences in the Pathogenicity of the p.H723R Mutation of the Common Deafness-Associated SLC26A4 Gene in Humans and Mice

Mutations in the SLC26A4 gene are a common cause of human hereditary hearing impairment worldwide. Previous studies have demonstrated that different SLC26A4 mutations have different pathogenetic mechanisms. By using a genotype-driven approach, we established a knock-in mouse model (i.e., Slc26a4^{tm2Dontuh/tm2Dontuh} mice) homozygous for the common p.H723R mutation in the East Asian population. To verify the pathogenicity of the p.H723R allele in mice, we further generated mice with compound heterozygous mutations (i.e., Slc26a4^{tm1Dontuh/tm2Dontuh}) by intercrossing Slc26a4^+/tm2Dontuh mice with Slc26a4^{tm1Dontuh/tm1Dontuh} mice, which segregated the c.919-2A>G mutation with an abolished Slc26a4 function. Mice were then subjected to audiologic assessments, a battery of vestibular evaluations, inner ear morphological studies, and noise exposure experiments. The results were unexpected; both Slc26a4^{tm2Dontuh/tm2Dontuh} and Slc26a4^{tm1Dontuh/tm2Dontuh} mice showed normal audiovestibular phenotypes and inner ear morphology, and they did not show significantly higher shifts in hearing thresholds after noise exposure than the wild-type mice. The results indicated not only the p.H723R allele was non-pathogenic in mice, but also a single p.H723R allele was sufficient to maintain normal inner ear physiology in heterozygous compound mice. There might be discrepancies in the pathogenicity of specific SLC26A4 mutations in humans and mice; therefore, precautions should be taken when extrapolating the results of animal studies to humans.     

幽门螺杆菌23s rRNA基因突变与克拉霉素耐药性关系的研究

目的:通过对幽门螺杆菌(Helicobacterpylori,HP)23s rRNA基因突变位点分析,观察23s rRNA各突变点与克拉霉素耐药的关系.方法:分离培养HP、提取DNA、扩增其23s rRNA基因片段及测序;运用Clustalw软件进行序列比对找出突变点.选用GenBank中已全基因组测序的35株HP,根据其mutY、ppa、efp和ureI4个管家基因建立Neighbour-joining树,根据进化树结果将35株HP分为欧非和东亚菌群;观察各突变点与菌群分布的关系.结果:与耐药有关的A2143G突变率为32.8％,T2182C突变率为90.6％但与耐药无关,其碱基分布具有菌群差异:东亚菌群以c碱基为主,欧非菌群以T为主(P＜0.05),其他可能与耐药有关的各位点分别为A2223G(6.25％)、T2190C(1.6％)、C2195T(1.6％).结论:青岛地区HP克拉霉素耐药率为32.8％并表现为23s rRNA基因A2143G突变,而2182位点突变是由于菌群分布差异导致的与克拉霉素耐药无关.     

Differences in Mucosal Gene Expression in the Colon of Two Inbred Mouse Strains after Colonization with Commensal Gut Bacteria

The host genotype has been proposed to contribute to individually composed bacterial communities in the gut. To provide deeper insight into interactions between gut bacteria and host, we associated germ-free C3H and C57BL/10 mice with intestinal bacteria from a C57BL/10 donor mouse. Analysis of microbiota similarity between the animals with denaturing gradient gel electrophoresis revealed the development of a mouse strain-specific microbiota. Microarray-based gene expression analysis in the colonic mucosa identified 202 genes whose expression differed significantly by a factor of more than 2. Application of bioinformatics tools demonstrated that functional terms including signaling/secretion, lipid degradation/catabolism, guanine nucleotide/guanylate binding and immune response were significantly enriched in differentially expressed genes. We had a closer look at the 56 genes with expression differences of more than 4 and observed a higher expression in C57BL/10 mice of the genes coding for Tlr1 and Ang4 which are involved in the recognition and response to gut bacteria. A higher expression of Pla2g2a was detected in C3H mice. In addition, a number of interferon-inducible genes were higher expressed in C3H than in C57BL/10 mice including Gbp1, Mal, Oasl2, Ifi202b, Rtp4, Ly6g6c, Ifi27l2a, Usp18, Ifit1, Ifi44, and Ly6g indicating that interferons may play an essential role in microbiota regulation. However, genes coding for interferons, their receptors, factors involved in interferon expression regulation or signaling pathways were not differentially expressed between the two mouse strains. Taken together, our study confirms that the host genotype is involved in the establishment of host-specific bacterial communities in the gut. Based on expression differences after colonization with the same bacterial inoculum, we propose that Pla2g2a and interferon-dependent genes may contribute to this phenomenon.     

An Animal Model of Type A Cystinuria Due to Spontaneous Mutation in 129S2/SvPasCrl Mice

Cystinuria is an autosomal recessive disease caused by the mutation of either SLC3A1 gene encoding for rBAT (type A cystinuria) or SLC7A9 gene encoding for b^0,+AT (type B cystinuria). Here, we evidenced in a commonly used congenic 129S2/SvPasCrl mouse substrain a dramatically high frequency of kidney stones that were similar to those of patients with cystinuria. Most of 129S2/SvPasCrl exhibited pathognomonic cystine crystals in urine and an aminoaciduria profile similar to that of patients with cystinuria. In addition, we observed a heterogeneous inflammatory infiltrate and cystine tubular casts in the kidney of cystinuric mice. As compared to another classical mouse strain, C57BL/6J mice, 129S2/SvPasCrl mice had an increased mortality associated with bilateral obstructive hydronephrosis. In 129S2/SvPasCrl mice, the heavy subunit rBAT of the tetrameric transporter of dibasic amino acids was absent in proximal tubules and we identified a single pathogenic mutation in a highly conserved region of the Slc3a1 gene. This novel mouse model mimicking human disease would allow us further pathophysiological studies and may be useful to analyse the crystal/tissue interactions in cystinuria.