Effects of Copper on Survival of Prion Protein Knockout Neurons and Glia

Abstract: The N-terminal region of the prion protein (PrP) contains an octameric repeat region suggested to bind copper. A 32-amino acid peptide (PrPOcta) based on this region in the protein was tested for its effects on cultured cerebellar cells. Cerebellar cells from mice deficient in cellular PrP (Prnp^0/0 mice) are more sensitive to copper toxicity and oxidative stress. PrPOcta selectively promotes the survival of Prnp^0/0 cerebellar cells. However, PrPOcta also reduces the toxicity of CuSO₄ on cerebellar cells and abolishes the difference in increased sensitivity of Prnp^0/0 cells to both copper toxicity and also oxidative stress from xanthine oxidase. PrPOcta does not promote the survival or proliferation of astrocytes or microglia. The survival-promoting effects of PrPOcta on neurons may be due to its ability to effectively chelate copper. The octameric repeat region of PrP may represent a functional domain of the native protein.     

Mitochondrial Gene Expression Profiles Are Associated with Maternal Psychosocial Stress in Pregnancy and Infant Temperament

Background

Gene-environment interactions mediate through the placenta and shape the fetal brain development. Between the environmental determinants of the fetal brain, maternal psychosocial stress in pregnancy has been shown to negatively influence the infant temperament development. This in turn may have adverse consequences on the infant neurodevelopment extending throughout the entire life-span. However little is known about the underlying biological mechanisms of the effects of maternal psychosocial stress in pregnancy on infant temperament. Environmental stressors such as maternal psychosocial stress in pregnancy activate the stress response cascade that in turn drives the increase in the cellular energy demand of vital organs with high metabolic rates such as, in pregnancy, the placenta. Key players of the stress response cascade are the mitochondria.

Results

Here, we tested the expression of all 13 protein-coding genes encoded by the mitochondria in 108 placenta samples from the Stress in Pregnancy birth cohort, a study that aims at determining the influence of in utero exposure to maternal psychosocial stress in pregnancy on infant temperament. We showed that the expression of the protein-coding mitochondrial-encoded gene MT-ND2 was positively associated with indices of maternal psychosocial stress in pregnancy including Prenatal Perceived Stress (β = 0.259; p-regression = 0.004; r²-regression = 0.120), State Anxiety (β = 0.218; p-regression = 0.003; r²-regression = 0.153), Trait Anxiety (β = 0.262; p-regression = 0.003; r²-regression = 0.129) and Pregnancy Anxiety Total (β = 0.208; p-regression = 0.010; r²-regression = 0.103). In the meantime MT-ND2 was negatively associated with the infant temperament indices of Activity Level (β = -0.257; p-regression = 0.008; r²-regression = 0.165) and Smile and Laughter (β = -0.286; p-regression = 0.036; r²-regression = 0.082). Additionally, MT-ND6 was associated with the maternal psychosocial stress in pregnancy index of Prenatal Perceived Stress (β = -0.231; p-regression = 0.004; r²-regression = 0.120), while MT-CO2 was associated with the maternal psychosocial stress in pregnancy indices of State Anxiety (β = 0.206; p-regression = 0.003; r²-regression = 0.153) and Trait Anxiety (β = 0.205; p-regression = 0.003; r²-regression = 0.129).

Conclusions

Our data support the role of mitochondria in responding to maternal psychosocial stress in pregnancy, as assessed in placenta, while also suggesting an important role for the mitochondria in the infant temperament development.     

Expression Levels of Obesity-Related Genes Are Associated with Weight Change in Kidney Transplant Recipients

Background

The aim of this study was to investigate the association of gene expression profiles in subcutaneous adipose tissue with weight change in kidney transplant recipients and to gain insights into the underlying mechanisms of weight gain.

Methodology/Principal Findings

A secondary data analysis was done on a subgroup (n = 26) of existing clinical and gene expression data from a larger prospective longitudinal study examining factors contributing to weight gain in transplant recipients. Measurements taken included adipose tissue gene expression profiles at time of transplant, baseline and six-month weight, and demographic data. Using multivariate linear regression analysis controlled for race and gender, expression levels of 1553 genes were significantly (p<0.05) associated with weight change. Functional analysis using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes classifications identified metabolic pathways that were enriched in this dataset. Furthermore, GeneIndexer literature mining analysis identified a subset of genes that are highly associated with obesity in the literature and Ingenuity pathway analysis revealed several significant gene networks associated with metabolism and endocrine function. Polymorphisms in several of these genes have previously been linked to obesity.

Conclusions/Significance

We have successfully identified a set of molecular pathways that taken together may provide insights into the mechanisms of weight gain in kidney transplant recipients. Future work will be done to determine how these pathways may contribute to weight gain.     

主要干性基因与衰老相关基因表达水平的相互拮抗关系

目前广泛地利用传统的体细胞衰老理论和方法对成体干细胞衰老进行研究,忽视了成体干细胞特有的自我更新功能和相应的干性基因的作用.干性基因的下调可能是导致间充质干细胞衰老的主要原因.通过查阅相关资料发现主要干性基因与衰老相关基因表达水平的相互拮抗关系,这体现在以下4个方面:a.干细胞衰老伴随着干性基因的下调;b.干性基因表达抑制细胞的衰老;c.干性基因抑制衰老相关基因的表达;d.抑制衰老相关基因促进干性基因的表达.干性基因与衰老相关基因的表达水平存在相互拮抗关系,这为成体干细胞衰老可能源于成体干细胞的干性降低的观点提供了坚实的分子基础.     

Prion Seeding Activities of Mouse Scrapie Strains with Divergent PrPSc Protease Sensitivities and Amyloid Plaque Content Using RT-QuIC and eQuIC

Different transmissible spongiform encephalopathy (TSE)-associated forms of prion protein (e.g. PrP^Sc) can vary markedly in ultrastructure and biochemical characteristics, but each is propagated in the host. PrP^Sc propagation involves conversion from its normal isoform, PrP^C, by a seeded or templated polymerization mechanism. Such a mechanism is also the basis of the RT-QuIC and eQuIC prion assays which use recombinant PrP (rPrP^Sen) as a substrate. These ultrasensitive detection assays have been developed for TSE prions of several host species and sample tissues, but not for murine models which are central to TSE pathogenesis research. Here we have adapted RT-QuIC and eQuIC to various murine prions and evaluated how seeding activity depends on glycophosphatidylinositol (GPI) anchoring and the abundance of amyloid plaques and protease-resistant PrP^Sc (PrP^Res). Scrapie brain dilutions up to 10⁻⁸ and 10⁻¹³ were detected by RT-QuIC and eQuIC, respectively. Comparisons of scrapie-affected wild-type mice and transgenic mice expressing GPI anchorless PrP showed that, although similar concentrations of seeding activity accumulated in brain, the heavily amyloid-laden anchorless mouse tissue seeded more rapid reactions. Next we compared seeding activities in the brains of mice with similar infectivity titers, but widely divergent PrP^Res levels. For this purpose we compared the 263K and 139A scrapie strains in transgenic mice expressing P101L PrP^C. Although the brains of 263K-affected mice had little immunoblot-detectable PrP^Res, RT-QuIC indicated that seeding activity was comparable to that associated with a high-PrP^Res strain, 139A. Thus, in this comparison, RT-QuIC seeding activity correlated more closely with infectivity than with PrP^Res levels. We also found that eQuIC, which incorporates a PrP^Sc immunoprecipitation step, detected seeding activity in plasma from wild-type and anchorless PrP transgenic mice inoculated with 22L, 79A and/or RML scrapie strains. Overall, we conclude that these new mouse-adapted prion seeding assays detect diverse types of PrP^Sc.     

Comparison of Gene Expression Profiles Between Pansensitive and Multidrug-Resistant Strains of Mycobacterium tuberculosis

Mycobacterium tuberculosis has developed resistance to anti-tuberculosis first-line drugs. Multidrug-resistant strains complicate the control of tuberculosis and have converted it into a worldwide public health problem. Mutational studies of target genes have tried to envisage the resistance in clinical isolates; however, detection of these mutations in some cases is not sufficient to identify drug resistance, suggesting that other mechanisms are involved. Therefore, the identification of new markers of susceptibility or resistance to first-line drugs could contribute (1) to specifically diagnose the type of M. tuberculosis strain and prescribe an appropriate therapy, and (2) to elucidate the mechanisms of resistance in multidrug-resistant strains. In order to identify specific genes related to resistance in M. tuberculosis, we compared the gene expression profiles between the pansensitive H37Rv strain and a clinical CIBIN:UMF:15:99 multidrug-resistant isolate using microarray analysis. Quantitative real-time PCR confirmed that in the clinical multidrug-resistant isolate, the esxG, esxH, rpsA, esxI, and rpmI genes were upregulated, while the lipF, groES, and narG genes were downregulated. The modified genes could be involved in the mechanisms of resistance to first-line drugs in M. tuberculosis and could contribute to increased efficiency in molecular diagnosis approaches of infections with drug-resistant strains.     

Identification of Genes Associated with Chlorophyll Accumulation in Flower Petals

Plants have an ability to prevent chlorophyll accumulation, which would mask the bright flower color, in their petals. In contrast, leaves contain substantial amounts of chlorophyll, as it is essential for photosynthesis. The mechanisms of organ-specific chlorophyll accumulation are unknown. To identify factors that determine the chlorophyll content in petals, we compared the expression of genes related to chlorophyll metabolism in different stages of non-green (red and white) petals (very low chlorophyll content), pale-green petals (low chlorophyll content), and leaves (high chlorophyll content) of carnation (Dianthus caryophyllus L.). The expression of many genes encoding chlorophyll biosynthesis enzymes, in particular Mg-chelatase, was lower in non-green petals than in leaves. Non-green petals also showed higher expression of genes involved in chlorophyll degradation, including STAY-GREEN gene and pheophytinase. These data suggest that the absence of chlorophylls in carnation petals may be caused by the low rate of chlorophyll biosynthesis and high rate of degradation. Similar results were obtained by the analysis of Arabidopsis microarray data. In carnation, most genes related to chlorophyll biosynthesis were expressed at similar levels in pale-green petals and leaves, whereas the expression of chlorophyll catabolic genes was higher in pale-green petals than in leaves. Therefore, we hypothesize that the difference in chlorophyll content between non-green and pale-green petals is due to different levels of chlorophyll biosynthesis. Our study provides a basis for future molecular and genetic studies on organ-specific chlorophyll accumulation.     

Maternal Factors Are Associated with the Expression of Placental Genes Involved in Amino Acid Metabolism and Transport

Introduction

Maternal environment and lifestyle factors may modify placental function to match the mother’s capacity to support the demands of fetal growth. Much remains to be understood about maternal influences on placental metabolic and amino acid transporter gene expression. We investigated the influences of maternal lifestyle and body composition (e.g. fat and muscle content) on a selection of metabolic and amino acid transporter genes and their associations with fetal growth.

Methods

RNA was extracted from 102 term Southampton Women’s Survey placental samples. Expression of nine metabolic, seven exchange, eight accumulative and three facilitated transporter genes was analyzed using quantitative real-time PCR.

Results

Increased placental LAT2 (p = 0.01), y ⁺ LAT2 (p = 0.03), aspartate aminotransferase 2 (p = 0.02) and decreased aspartate aminotransferase 1 (p = 0.04) mRNA expression associated with pre-pregnancy maternal smoking. Placental mRNA expression of TAT1 (p = 0.01), ASCT1 (p = 0.03), mitochondrial branched chain aminotransferase (p = 0.02) and glutamine synthetase (p = 0.05) was positively associated with maternal strenuous exercise. Increased glutamine synthetase mRNA expression (r = 0.20, p = 0.05) associated with higher maternal diet quality (prudent dietary pattern) pre-pregnancy. Lower LAT4 (r = -0.25, p = 0.05) and aspartate aminotransferase 2 mRNA expression (r = -0.28, p = 0.01) associated with higher early pregnancy diet quality. Lower placental ASCT1 mRNA expression associated with measures of increased maternal fat mass, including pre-pregnancy BMI (r = -0.26, p = 0.01). Lower placental mRNA expression of alanine aminotransferase 2 associated with greater neonatal adiposity, for example neonatal subscapular skinfold thickness (r = -0.33, p = 0.001).

Conclusion

A number of maternal influences have been linked with outcomes in childhood, independently of neonatal size; our finding of associations between placental expression of transporter and metabolic genes and maternal smoking, physical activity and diet raises the possibility that their effects are mediated in part through alterations in placental function. The observed changes in placental gene expression in relation to modifiable maternal factors are important as they could form part of interventions aimed at maintaining a healthy lifestyle for the mother and for optimal fetal development.     

Endothelins Induce Fos Expression in Neurons and Glia in Organotypic Cultures of Rat Cerebellum

Abstract: Endothelins (ETs) and their receptors are present in high levels in the brain and have been proposed to act as neuromodulators or neurotransmitters. However, neither their role nor their precise mechanism of action in the brain is understood. In this study, c- fos expression was used as a marker of neuronal activation in organotypic cultures of rat cerebellum. ETs induced Fos protein expression in both granule cells and glia but not in Purkinje cells. Granule cells and glia were both very sensitive to ETs, but different receptor subtypes appeared to be involved, because granule cells did not respond to ET-3. However, they did respond to the ET_B-selective agonist BQ3020, suggesting the possible existence of a novel neuronal ET_B-like receptor. The induction of Fos in granule cells was independent of extracellular calcium ion concentration, but the ryanodine receptor antagonist dantrolene significantly inhibited the response to ETs, suggesting that the mobilisation of calcium ions from intracellular stores is important. These data support previous evidence that ETs act directly on neurones and show that the intracellular pathways after ET receptor activation are complex. It appears likely that ETs play an important neuromodulatory role in the cerebellum.     

PrP Expression,PrPSc Accumulation and Innervation of Splenic Compartments in Sheep Experimentally Infected with Scrapie

Background

In prion disease, the peripheral expression of PrP^C is necessary for the transfer of infectivity to the central nervous system. The spleen is involved in neuroinvasion and neural dissemination in prion diseases but the nature of this involvement is not known. The present study undertook the investigation of the spatial relationship between sites of PrP^Sc accumulation, localisation of nerve fibres and PrP^C expression in the tissue compartments of the spleen of scrapie-inoculated and control sheep.

Methodology/Principal Findings

Laser microdissection and quantitative PCR were used to determine PrP mRNA levels and results were compared with immunohistochemical protocols to distinguish PrP^C and PrP^Sc in tissue compartments of the spleen. In sheep experimentally infected with scrapie, the major sites of accumulation of PrP^Sc in the spleen, namely the lymphoid nodules and the marginal zone, expressed low levels of PrP mRNA. Double immunohistochemical labelling for PrP^Sc and the pan-nerve fibre marker, PGP, was used to evaluate the density of innervation of splenic tissue compartments and the intimacy of association between PrP^Sc and nerves. Some nerve fibres were observed to accompany blood vessels into the PrP^Sc-laden germinal centres. However, the close association between nerves and PrP^Sc was most apparent in the marginal zone. Other sites of close association were adjacent to the wall of the central artery of PALS and the outer rim of germinal centres.

Conclusions/Significance

The findings suggest that the degree of PrP^Sc accumulation does not depend on the expression level of PrP^C. Though several splenic compartments may contribute to neuroinvasion, the marginal zone may play a central role in being the compartment with most apparent association between nerves and PrP^Sc.     

Increased Dendritic Spine Density and Tau Expression Are Associated with Individual Differences in Steroidal Regulation of Male Sexual Behavior

Male sexual behavior (MSB) is modulated by gonadal steroids, yet this relationship is highly variable across species and between individuals. A significant percentage (∼30%) of B6D2F1 hybrid male mice demonstrate MSB after long-term orchidectomy (herein after referred to as “maters”), providing an opportunity to examine the mechanisms that underlie individual differences in steroidal regulation of MSB. Use of gene expression arrays comparing maters and non-maters has provided a first pass look at the genetic underpinnings of steroid-independent MSB. Surprisingly, of the ∼500 genes in the medial preoptic area (MPOA) that differed between maters and non-maters, no steroid hormone or receptor genes were differentially expressed between the two groups. Interestingly, best known for their association with Alzheimer’s disease, amyloid precursor protein (APP) and the microtubule-associated protein tau (MAPT) were elevated in maters. Increased levels of their protein products (APP and tau) in their non-pathological states have been implicated in cell survival, neuroprotection, and supporting synaptic integrity. Here we tested transgenic mice that overexpress tau and found facilitated mounting and intromission behavior after long-term orchidectomy relative to littermate controls. In addition, levels of synaptophysin and spinophilin, proteins generally enriched in synapses and dendritic spines respectively, were elevated in the MPOA of maters. Dendritic morphology was also assessed in Golgi-impregnated brains of orchidectomized B6D2F1 males, and hybrid maters exhibited greater dendritic spine density in MPOA neurons. In sum, we show for the first time that retention of MSB in the absence of steroids is correlated with morphological differences in neurons.     

Identification and Characterization of Nucleotide Sequence Differences in Three Virulence-Associated Genes of Listeria monocytogenes Strains Representing Clinically Important Serotypes

Listeria monocytogenes is a Gram-positive, facultative intracellular bacterium that causes invasive, often fatal, disease in susceptible hosts. As a foodborne pathogen, the bacterium has emerged as a significant public health problem and has caused several epidemics in the United States and Europe. Three serotypes (1/2a, 1/2b, 4b) of L. monocytogenes are responsible for nearly 95% of all reported cases of human listeriosis. L. monocytogenes serotype 4b has caused all well-characterized foodborne epidemic outbreaks in North America and Europe between 1981 and 1993. However, most of the genetic studies to characterize virulence factors of L. monocytogenes have been done by using serotypes 1/2a and 1/2c. In this investigation, we examined three virulence-associated genes (hly encoding listeriolysin, plcA encoding phosphotidylinositol-specific phospholipase C, and inlA encoding internalin) of two serotype 4b and two serotype 1/2b strains. We chose these virulence-associated genes on the basis of published sequence differences among strains from Listeria subgroups containing serotypes 1/2a and 1/2c versus 4b, respectively. They correspond to sequence homologies that include very highly conserved (hlyA), highly conserved (plcA) and mostly conserved (inlA). We found by using nucleotide sequence analysis of the hly, plcA, and inlA genes, the two L. monocytogenes strains (including a strain associated with a foodborne disease outbreak in California in 1985) in this study, two serotype 1/2b strains from a study that we recently reported, and other similar published data for serotypes 1/2a, 1/2c, and 4b, had a high degree of sequence conservation at the gene and protein levels for all three genes. However, the sequences for the hly gene of L. monocytogenes strains of serotypes 1/2b and 4b were more closely related to each other and showed significant divergence from serotypes 1/2a and 1/2c. A unique nonsynonymous mutation was found in the hly gene of L. monocytogenes isolates that were associated with the 1985 California outbreak and were the epidemic phage type. When 158 L. monocytogenes isolates from the collection at the Centers for Disease Control and Prevention were screened, the mutation was found only in one other strain that had been isolated in California 3 years before the epidemic. Although the California epidemic clone was lactose negative, other L. monocytogenes serotype 4b isolates that were lactose negative did not possess the unique mutation observed in that epidemic clone. Received: 18 June 1997 / Accepted: 4 December 1997     

Effects of Alpha-Synuclein on Primary Spinal Cord Neurons Associated with Apoptosis and CNTF Expression

Spinal cord injury (SCI) often causes neurological deficits with poor recovery; the treatment, however, is far from satisfaction, and the mechanisms remain unclear. Using immunohistochemistry and western blotting analysis, we found α-synuclein (SNCA) was significantly up-regulated in the spinal caudal segment of rats subjected to spinal cord transection at 3 days post-operation. Moreover, the role of SNCA on neuronal growth and apoptosis in vitro was determined by using overexpressing and interfering SNCA recombined plasmid vectors, and the underlying mechanism was detected by QRT-PCR and western blotting. Spinal neurons transfected with SNCA-shRNA lentivirus gave rise to an optimal neuronal survival, while it results in cell apoptosis in SNCA-ORF group. In molecular level, SNCA silence induced the up-regulation of CNTF and down-regulation of Caspase7/9. Together, endogenous SNCA plays a crucial role in spinal neuronal survival, in which the underlying mechanism may be linked to the regulation both apoptotic genes (Caspase7/9) and CNTF. The present findings therefore provide novel insights into the role of SNCA in spinal cord and associated mechanism, which may provide novel cue for the treatment of SCI in future clinic trials.     

Expression and Stability of Arabidopsis CDC6 Are Associated with Endoreplication

Studies on the CDC6 protein, which is crucial to the control of DNA replication in yeast and animal cells, are lacking in plants. We have isolated an Arabidopsis cDNA encoding the AtCDC6 protein and studied its possible connection to the occurrence of developmentally regulated endoreplication cycles. The AtCDC6 gene is expressed maximally in early S-phase, and its promoter contains an E2F consensus site that mediates the binding of a plant E2F/DP complex. Transgenic plants carrying an AtCDC6 promoter-beta-glucuronidase fusion revealed that it is active in proliferating cells and, interestingly, in endoreplicating cells. In particular, the extra endoreplication cycle that occurs in dark-grown hypocotyl cells is associated with upregulation of the AtCDC6 gene. This was corroborated using ctr1 Arabidopsis mutants altered in their endoreplication pattern. The ectopic expression of AtCDC6 in transgenic plants induced endoreplication and produced a change in the somatic ploidy level. AtCDC6 was degraded in a ubiquitin- and proteosome-dependent manner by extracts from proliferating cells, but it was degraded poorly by extracts from dark-grown hypocotyl endoreplicating cells. Our results indicate that endoreplication is associated with expression of the AtCDC6 gene and, most likely, the stability of its product; it also apparently requires activation of the retinoblastoma/E2F/DP pathway. These conclusions may apply to endoreplicating cells in other tissues of the plant and to endoreplicating cells in other eukaryotes.     

Genetic Analysis in the Colonia Strain of PHYSARUM POLYCEPHALUM: Heterothallic Strains That Mate with and Are Partially Isogenic to the Colonia Strain

Amoebae of the Colonia (CL) strain, which normally produce plasmodia in clones, are shown to cross with mt3 and mt4 amoebae under appropriate conditions. Strains carrying mt3 and mt4 in a CL genetic background were constructed and used in the genetic analysis of mutants isolated in CL.     

不同花色菊花品种花色素结构基因的表达特性

对红色、黄色、粉紫色和白色菊花品种不同开放度的花序舌状花中CHS、CHI、DFR、F3H、F3′H和3GT基因的表达量进行了相对定量分析。结果表显示:6个基因的表达因不同花色、不同发育阶段而异。‘钟山红鹰’(红色)中各基因的表达量均较高,且均在Ⅱ(松蕾期)或Ⅲ(半开期)期达到峰值,其中DFR、3GT基因的表达量远高于其他花色品种。‘金陵娇黄’(黄色)中CHS、CHI基因表达量较高,且Ⅰ(紧蕾期)、Ⅱ期表达量高于Ⅲ、Ⅳ(盛开期)期;3GT、DFR基因表达量分别高或低于‘金陵笑靥’(粉紫色)品种中相应基因的表达量,但均比红色品种低;F3H在4个品种中表达量最低,F3′H表达量接近或略低于红色或粉紫色品种,且各阶段表达水平较稳定。‘金陵笑靥’中DFR表达量仅次于‘钟山红鹰’,3GT和CHS表达量低于红色与黄色品种。‘钟山雪桂’(白色)中各基因仅有微量表达,除F3H外各基因的表达量明显低于其他花色品种。研究表明,花色素结构基因DFR、3GT是菊花花色素合成的关键基因,DFR很可能是限速关键基因,一定表达水平的CHS、CHI也是菊花花色素合成所必须的,F3H基因与花色素合成不存在直接相关。     

Classification of Genes and Putative Biomarker Identification Using Distribution Metrics on Expression Profiles

Background

Identification of genes with switch-like properties will facilitate discovery of regulatory mechanisms that underlie these properties, and will provide knowledge for the appropriate application of Boolean networks in gene regulatory models. As switch-like behavior is likely associated with tissue-specific expression, these gene products are expected to be plausible candidates as tissue-specific biomarkers.

Methodology/Principal Findings

In a systematic classification of genes and search for biomarkers, gene expression profiles (GEPs) of more than 16,000 genes from 2,145 mouse array samples were analyzed. Four distribution metrics (mean, standard deviation, kurtosis and skewness) were used to classify GEPs into four categories: predominantly-off, predominantly-on, graded (rheostatic), and switch-like genes. The arrays under study were also grouped and examined by tissue type. For example, arrays were categorized as ‘brain group’ and ‘non-brain group’; the Kolmogorov-Smirnov distance and Pearson correlation coefficient were then used to compare GEPs between brain and non-brain for each gene. We were thus able to identify tissue-specific biomarker candidate genes.

Conclusions/Significance

The methodology employed here may be used to facilitate disease-specific biomarker discovery.     

Expression Profiles of Different Cytokine Genes in Peripheral Blood Mononuclear Cells of Goats Infected Experimentally with Native Strain of Mycobacterium Avium Subsp. Paratuberculosis

Paratuberculosis (ParaTB), caused by Mycobacterium avium subspecies paratuberculosis (MAP) is a chronic enteritis of ruminants and may contribute to Crohn's disease in humans. Key features of host immunity to MAP infection include an early pro-inflammatory (Th1-like) response that eventually gives way to a predominant anti-inflammatory (Th2-like) response. Many studies have been conducted to understand the underlying mechanism of misdirected host immune response, however, these studies mainly focused on cattle. The present study is the first attempt to test the hypothesis of shift in Th1 to Th2 like responses during the progression of ParaTB in caprine species (small ruminant). Ten healthy male kids (<6 months old) of the same breed were selected for this study. Of the 10 kids, 6 were experimentally infected with native strain (S5) of MAP (“Indian Bison Type”) and the remaining 4 kids were control. Kids were monitored for a period of 12 months post infection (MPI) and were tested for establishment of infection. Expression levels of IFNG, IL2, IL12, IL4, and IL10 genes were estimated before infection and at 4, 8, and 12 MPI in stimulated peripheral blood mononuclear cells (PBMCs) of infected and control kids. The study demonstrated the expression of IFNG and IL2 as classic Th1-like pro-inflammatory signatures; whereas, IL10 exhibited itself as classical Th2-like signature. The study also reports unexpected lowered expression of the IL12 gene simultaneously with increased expression of IFNG, lowered expression of the IL2 gene (compared to IFNG), and suppressed expression of the IL4.