Tissue-specific Changes Research Articles

Spontaneous and Naloxone-Precipitated Withdrawal Behaviors From Chronic Opiates are Accompanied by Changes in N-Oleoylglycine and N-Oleoylalanine Levels in the Brain and Ameliorated by Treatment With These Mediators.

Rationale: The endocannabinoidome mediators, N-Oleoylglycine (OlGly) and N-Oleoylalanine (OlAla), have been shown to reduce acute naloxone-precipitated morphine withdrawal affective and somatic responses.Objectives: To determine the role and mechanism of action of OlGly and OlAla in withdrawal responses from chronic exposure to opiates in male Sprague-Dawley rats.Methods: Opiate withdrawal was produced: 1) spontaneously 24 h following chronic exposure to escalating doses of morphine over 14 days (Experiments 1 and 2) and steady-state exposure to heroin by minipumps for 12 days (Experiment 3), 2) by naloxone injection during steady-state heroin exposure (Experiment 4), 3) by naloxone injection during operant heroin self-administration (Experiment 5).Results: In Experiment 1, spontaneous morphine withdrawal produced somatic withdrawal reactions. The behavioral withdrawal reactions were accompanied by suppressed endogenous levels of OlGly in the nucleus accumbens, amygdala, and prefrontal cortex, N-Arachidonylglycerol and OlAla in the amygdala, 2-arachidonoylglycerol in the nucleus accumbens, amygdala and interoceptive insular cortex, and by changes in colonic microbiota composition. In Experiment 2, treatment with OlAla, but not OlGly, reduced spontaneous morphine withdrawal responses. In Experiment 3, OlAla attenuated spontaneous steady-state heroin withdrawal responses at both 5 and 20 mg/kg; OlGly only reduced withdrawal responses at the higher dose of 20 mg/kg. Experiment 4 demonstrated that naloxone-precipitated heroin withdrawal from steady-state exposure to heroin (7 mg/kg/day for 12 days) is accompanied by tissue-specific changes in brain or gut endocannabinoidome mediator, including OlGly and OlAla, levels and colonic microbiota composition, and that OlAla (5 mg/kg) attenuated behavioural withdrawal reactions, while also reversing some of the changes in brain and gut endocannabinoidome and gut microbiota induced by naloxone. Experiment 5 demonstrated that although OlAla (5 mg/kg) did not interfere with operant heroin self-administration on its own, it blocked naloxone-precipitated elevation of heroin self-administration behavior.Conclusion: These results suggest that OlAla and OlGly are two endogenous mediators whose brain concentrations respond to chronic opiate treatment and withdrawal concomitantly with changes in colon microbiota composition, and that OlAla may be more effective than OlGly in suppressing chronic opiate withdrawal responses.

Morphological changes after cranial fractionated photon radiotherapy: Localized loss of white matter and grey matter volume with increasing dose

PurposeNumerous brain MR imaging studies have been performed to understand radiation-induced cognitive decline. However, many of them focus on a single region of interest, e.g. cerebral cortex or hippocampus. In this study, we use deformation-based morphometry (DBM) and voxel-based morphometry (VBM) to measure the morphological changes in patients receiving fractionated photon RT, and relate these to the dose. Additionally, we study tissue specific volume changes in white matter (WM), grey matter (GM), cerebrospinal fluid and total intracranial volume (TIV). Methods and materialsFrom our database, we selected 28 patients with MRI of high quality available at baseline and 1 year after RT. Scans were rigidly registered to each other, and to the planning CT and dose file. We used DBM to study non-tissue-specific volumetric changes, and VBM to study volume loss in grey matter. Observed changes were then related to the applied radiation dose (in EQD2). Additionally, brain tissue was segmented into WM, GM and cerebrospinal fluid, and changes in these volumes and TIV were tested. ResultsPerforming DBM resulted in clusters of dose-dependent volume loss 1 year after RT seen throughout the brain. Both WM and GM were affected; within the latter both cerebral cortex and subcortical nuclei show volume loss. Volume loss rates ranging from 5.3 to 15.3%/30 Gy were seen in the cerebral cortical regions in which more than 40% of voxels were affected. In VBM, similar loss rates were seen in the cortex and nuclei. The total volume of WM and GM significantly decreased with rates of 5.8% and 2.1%, while TIV remained unchanged as expected. ConclusionsRadiotherapy is associated with dose-dependent intracranial morphological changes throughout the entire brain. Therefore, we will consider to revise sparing of organs at risk based on future cognitive and neurofunctional data.

Cultivar and tissue-specific changes of abscisic acid, its catabolites and individual sugars during postharvest handling of flat peaches (Prunus persica cv. platycarpa)

The role of abscisic acid (ABA) during postharvest ripening of peaches remains unclear. This study aimed to investigate the temporal and tissue-specific changes in ABA, and ABA catabolites, of two flat peach cultivars, ‘Plane Sun’ and ‘Platibell’, during the stone fruit supply chain. The relationship between ABA catabolism, ethylene production, individual sugar changes and fruit firmness was also studied. We found that flat peaches can produce and metabolise ABA during postharvest ripening, and that this is cultivar and tissue dependent. Our results demonstrated that a burst in ABA concentration preceded that of ethylene production in ‘Plane Sun’ fruit, suggesting cross-talk between the two hormones. ABA and ethylene were both negatively correlated with fruit firmness, whilst sugar content, especially glucose, was only correlated with ABA. In conclusion, ABA may trigger ethylene production changes while also affecting sugar metabolism leading to fruit softening and over-ripening associated processes during stone fruit postharvest handling.

Hedgehog dysregulation contributes to tissue-specific inflammaging of resident macrophages.

Age-associated low-grade sterile inflammation, commonly referred to as inflammaging, is a recognized hallmark of aging, which contributes to many age-related diseases. While tissue-resident macrophages are innate immune cells that secrete many types of inflammatory cytokines in response to various stimuli, it is not clear whether they have a role in driving inflammaging. Here we characterized the transcriptional changes associated with physiological aging in mouse resident macrophage populations across different tissues and sexes. Although the age-related transcriptomic signatures of resident macrophages were strikingly tissue-specific, the differentially expressed genes were collectively enriched for those with important innate immune functions such as antigen presentation, cytokine production, and cell adhesion. The brain-resident microglia had the most wide-ranging age-related alterations, with compromised expression of tissue-specific genes and relatively exaggerated responses to endotoxin stimulation. Despite the tissue-specific patterns of aging transcriptomes, components of the hedgehog (Hh) signaling pathway were decreased in aged macrophages across multiple tissues. In vivo suppression of Hh signaling in young animals increased the expression of pro-inflammatory cytokines, while in vitro activation of Hh signaling in old macrophages, in turn, suppressed the expression of these inflammatory cytokines. This suggests that hedgehog signaling could be a potential intervention axis for mitigating age-associated inflammation and related diseases. Overall, our data represent a resourceful catalog of tissue-specific and sex-specific transcriptomic changes in resident macrophages of peritoneum, liver, and brain, during physiological aging.

Longitudinal changes of spinal cord grey and white matter following spinal cord injury

ObjectivesTraumatic and non-traumatic spinal cord injury produce neurodegeneration across the entire neuraxis. However, the spatiotemporal dynamics of spinal cord grey and white matter neurodegeneration above and below the injury is...

Tissue specific changes in elements and organic compounds of alfalfa (Medicago sativa L.) cultivars differing in salt tolerance under salt stress

Soil salinity is a global concern and often the primary factor contributing to land degradation, limiting crop growth and production. Alfalfa (Medicago sativa L.) is a low input high value forage legume with a wide adaptation. Examining the tissue-specific responses to salt stress will be important to understanding physiological changes of alfalfa. The responses of two alfalfa cultivars (salt tolerant ‘Halo’, salt intolerant ‘Vernal’) were studied for 12 weeks in five gradients of salt stress in a sand based hydroponic system in the greenhouse. The accumulation and localization of elements and organic compounds in different tissues of alfalfa under salt stress were evaluated using synchrotron beamlines. The pattern of chlorine accumulation for ‘Halo’ was: root > stem ~ leaf at 8 dSm−1, and root ~ leaf > stem at 12 dSm−1, potentially preventing toxic ion accumulation in leaf tissues. In contrast, for ‘Vernal’, it was leaf > stem ~ root at 8 dSm−1 and leaf > root ~ stem at 12 dSm−1. The distribution of chlorine in ‘Halo’ was relatively uniform in the leaf surface and vascular bundles of the stem. Amide concentration in the leaf and stem tissues was greater for ‘Halo’ than ‘Vernal’ at all salt gradients. This study determined that low ion accumulation in the shoot was a common strategy in salt tolerant alfalfa up to 8 dSm−1 of salt stress, which was then replaced by shoot tissue tolerance at 12 dSm−1.

Arc1 and the microbiota together modulate growth and metabolic traits in Drosophila.

Perturbations to animal-associated microbial communities (the microbiota) have deleterious effects on various aspects of host fitness, but the molecular processes underlying these impacts are poorly understood. Here, we identify a connection between the microbiota and the neuronal factor Arc1 that affects growth and metabolism in Drosophila. We find that Arc1 exhibits tissue-specific microbiota-dependent expression changes, and that germ-free flies bearing a null mutation of Arc1 exhibit delayed and stunted larval growth, along with a variety of molecular, cellular and organismal traits indicative of metabolic dysregulation. Remarkably, we show that the majority of these phenotypes can be fully suppressed by mono-association with a single Acetobacter sp. isolate, through mechanisms involving both bacterial diet modification and live bacteria. Additionally, we provide evidence that Arc1 function in key neuroendocrine cells of the larval brain modulates growth and metabolic homeostasis under germ-free conditions. Our results reveal a role for Arc1 in modulating physiological responses to the microbial environment, and highlight how host-microbe interactions can profoundly impact the phenotypic consequences of genetic mutations in an animal host.

Jasmonic Acid Plays a Pivotal Role in Pollen Development and Fertility Regulation in Different Types of P(T)GMS Rice Lines.

Two-line hybrid rice systems represent a new technical approach to utilizing the advantages of rice hybrids. However, the mechanism underlying the male sterile-line fertility transition in rice remains unclear. Peiai 64S (PA64S) is a photoperiod- and thermo-sensitive genic male sterile (PTGMS) line in which male sterility manifests at an average temperature above 23.5 °C under long-day (LD) conditions. Nongken 58S (NK58S) is a LD-sensitive genic male sterile (PGMS) rice that is sterile under LD conditions (above 13.75 h-day). In contrast, D52S is a short-day (SD)-PGMS line that manifests male sterility under SD conditions (below 13.5 h-day). In this study, we obtained fertile and sterile plants from all three lines and performed transcriptome analyses on the anthers of the plants. Gene ontology (GO) analysis suggested that the differentially expressed genes identified were significantly enriched in common terms involved in the response to jasmonic acid (JA) and in JA biosynthesis. On the basis of the biochemical and molecular validation of dynamic, tissue-specific changes in JA, indole-3-acetic acid (IAA) levels, gibberellin (GA) levels, and JA biosynthetic enzyme activities and expression, we proposed that JA could play a pivotal role in viable pollen production through its initial upregulation, constant fluctuation and leaf-spikelet signaling under certain fertility-inducing conditions. Furthermore, we also sprayed methyl jasmonate (MEJA) and salicylhydroxamic acid (SHAM) on the plants, thereby achieving fertility reversal in the PGMS lines NK58S and D52S, with 12.91–63.53% pollen fertility changes. Through qPCR and enzyme activity analyses, we identified two key enzymes—allene oxide synthase (AOS) and allene oxide cyclase (AOC)—that were produced and upregulated by 20–500-fold in PGMS in response to spraying; the activities of these enzymes reversed pollen fertility by influencing the JA biosynthetic pathway. These results provide a new understanding of hormone interactions and networks in male-sterile rice based on the role of JA that will help us to better understand the potential regulatory mechanisms of fertility development in rice in the future.

A 1-Month Ketogenic Diet Increased Mitochondrial Mass in Red Gastrocnemius Muscle, but Not in the Brain or Liver of Middle-Aged Mice.

Alterations in markers of mitochondrial content with ketogenic diets (KD) have been reported in tissues of rodents, but morphological quantification of mitochondrial mass using transmission electron microscopy (TEM), the gold standard for mitochondrial quantification, is needed to further validate these findings and look at specific regions of interest within a tissue. In this study, red gastrocnemius muscle, the prefrontal cortex, the hippocampus, and the liver left lobe were used to investigate the impact of a 1-month KD on mitochondrial content in healthy middle-aged mice. The results showed that in red gastrocnemius muscle, the fractional area of both subsarcolemmal (SSM) and intermyofibrillar (IMM) mitochondria was increased, and this was driven by an increase in the number of mitochondria. Mitochondrial fractional area or number was not altered in the liver, prefrontal cortex, or hippocampus following 1 month of a KD. These results demonstrate tissue-specific changes in mitochondrial mass with a short-term KD and highlight the need to study different muscle groups or tissue regions with TEM to thoroughly determine the effects of a KD on mitochondrial mass.

E2F/Dp inactivation in fat body cells triggers systemic metabolic changes.

The E2F transcription factors play a critical role in controlling cell fate. In Drosophila, the inactivation of E2F in either muscle or fat body results in lethality, suggesting an essential function for E2F in these tissues. However, the cellular and organismal consequences of inactivating E2F in these tissues are not fully understood. Here, we show that the E2F loss exerts both tissue-intrinsic and systemic effects. The proteomic profiling of E2F-deficient muscle and fat body revealed that E2F regulates carbohydrate metabolism, a conclusion further supported by metabolomic profiling. Intriguingly, animals with E2F-deficient fat body had a lower level of circulating trehalose and reduced storage of fat. Strikingly, a sugar supplement was sufficient to restore both trehalose and fat levels, and subsequently rescued animal lethality. Collectively, our data highlight the unexpected complexity of E2F mutant phenotype, which is a result of combining both tissue-specific and systemic changes that contribute to animal development.

Hydralazine as a Versatile and Universal Matrix for High-Molecular Coverage and Dual-Polarity Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging.

Few matrices have the potential to be universally applicable for imaging vast endogenous compounds ranging from micro to macromolecules. In this article, we present hydralazine (HZN) as a versatile and universal matrix for matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) of a wide range of endogenous compounds between 50.0 and 20,000.0 Da. HZN was prepared from its hydrochloride by alkalizing HZN·HCl with ammonia to enhance the optical absorptivity at the preferred MALDI UV laser wavelength. To further improve its performance for MALDI MS, HZN was doped with NH4OH or TFA, resulting in matrix superior performance for imaging biologically relevant compounds in the negative and positive-ion modes, respectively. The analyte-matrix interaction was also enhanced by the optimized matrix solvent and the deposition amount. Compared with conventional matrices such as 2,5-dihydroxybenzoic acid, α-cyano-4-hydroxycinnamic acid, and 9-aminoacridine (9-AA), the HZN matrix provided higher sensitivity, broader molecular coverage, and improved signal intensities. Its broad acquisition range makes it versatile for imaging small molecular metabolites and lipids, as well as proteins. In addition, HZN was applied successfully for the visualization of tissue-specific distributions and changes of small molecules, lipids, and proteins in the kidney and liver sections of obese ob/ob and diabetic db/db mice. The use of the HZN matrix shows great potential application in the field of pathological research.

Dietary Sodium Restriction Results in Tissue-Specific Changes in DNA Methylation in Humans.

[Figure: see text].

The Potential Use of DNA Methylation Patterns from Peripheral Blood Leukocytes as a Surrogate for Stress Axis Tissues in Mature Brahman Cows

Abstract DNA methylation (DNAm) patterns are tissue specific and aid in tissue specific gene expression changes. The use of DNAm patterns from peripheral blood leukocytes (PBL) as a surrogate for patterns in other tissues is common, especially in longitudinal studies when sampling of tissues is not plausible. Thus, the objective of this study was to investigate the suitability of using DNAm patterns of PBL as a surrogate for the DNAm patterns in neuroendocrine tissues responsible for stress responses and energy metabolism. Samples from the paraventricular region of the hypothalamus, anterior pituitary gland, adrenal cortex, and the adrenal medulla were harvested from 5-yr-old Brahman cows (n = 8) and DNA was extracted from each sample. Methylation was assessed using reduced representation sodium bisulfite sequencing and differentially methylated regions (DMR) between the PBL DNA and tissue DNA were identified using EdgeR from Bioconductor, R. Analysis revealed over 15,000 DMRs located within promoter regions of genes in each tissue, with the majority of the sites having increased methylation in the PBL (Table 1). To further evaluate the use of PBL DNA as a surrogate, Pearson correlation values were calculated for genes (n = 20) pertinent to each respective tissue using the mean methylation of the specific gene in the PBL and in the tissue (Table 2). Three correlations were significant (P ≤ 0.05), two of which were negative. The sizable differences indicate that DNA methylation patterns from PBL do not compare well to patterns from hypothalamic, pituitary, adrenal cortex, and adrenal medulla tissues from 5-yr-old Brahman cows. This is especially the case for the majority of the specific genes examined in this study. Whether DNAm in the surrogate PBL will shift in a direction similar to that of specific tissues of Brahman cows exposed to stressful stimuli during developmental periods remains to be determined.

Developmental Programming: Prenatal Bisphenol A Induces Non-Monotonic Changes in Epigenetic Modulators in Metabolic Tissues of Female Sheep

Developmental exposure to endocrine disruptor bisphenol A (BPA) is associated \\with metabolic defects during adulthood in the female sheep. These are characterized by peripheral insulin resistance and increase in negative mediators of insulin sensitivity such as oxidative stress in metabolic tissues, lipotoxicity in liver and muscle and adipocyte hypertrophy in visceral (VAT) and subcutaneous (SAT) adipose tissue. Conceivably, developmental impact of BPA on regulators of insulin sensitivity involves changes in epigenetic machinery and mediated via changes in expression of enzymes that induce covalent modifications of DNA and histone. To determine the impact of prenatal BPA exposure on epigenetic enzymes [DNA methyltransferases (DNMT), histone deacetylases (HDAC), histone acetyl transferase EP300, histone methylases (SUV39H1, SMYD3 and EZH2) and histone demethylase KDM1A], metabolic tissues (liver, muscle, VAT and SAT) were collected from 21-month-old female offspring born to mothers treated with 0, 0.05, 0.5, or 5 mg/kg/day of BPA from days 30-90 of gestation. Data were analyzed by Cohen’s effect size analysis and large magnitude differences (Cohens d>0.8) discussed. In liver, prenatal BPA induced: 1) a decrease in DNMT1 and 3B at all doses and DNMT3A at the highest dose, 2) a decrease in histone deacetylase HDAC3 as opposed to increase in acetylase EP300 at the highest dose, 3) a decrease in SUV39H1 at the two higher doses, and 4) an increase in EZH2 only with 0.5 mg dose. The prenatal BPA-induced changes in muscle include: 1) increases in expression of DNMTs and EP300 at all doses, 2) an increase in SUV39H1 at 0.5 mg dose and EZH2 at 0.05 and 0.5 mg doses, and 3) decreases in SMYD3 at the lowest dose and KDM1A with 0.05 and 5 mg doses. Prenatal BPA treatment also induced depot-specific changes at the adipose tissue level. In the VAT prenatal BPA induced: 1) increases in expression of all DNMTs examined 2) increases in HDAC2 at all doses except HDAC3 only at 0.05 and 0.5mg dose and 3) increases in histone acetylase EP300 at all doses. In SAT BPA induced: 1) decrease in DNMT3A at 0.5mg and increase at 5 mg, 2) decreases in HDAC1 and HDAC2 at the lowest dose, 3) an increase in HDAC3 at the medium dose, and 4) a decrease in EP300 at the lowest dose. Contrasting changes in histone methylation modifying enzymes were also evident between VAT and SAT manifested as increases in SUV39H1 at the two higher doses and SMYD3 at all three doses in the VAT as opposed to decrease in SUV39H1 and SMYD3 at 0.05 and 0.5 mg doses and EZH2 and KDM1A at the lowest dose in the SAT. These findings indicating developmental exposure to BPA induces non-monotonic dose responses in epigenetic modifying enzymes are consistent with the premise that changes in epigenetic machinery underlie the metabolic disruptions induced by prenatal BPA treatment likely accounting for the tissue specific changes in insulin sensitivity. (support by R01-ES-016541)

N‐cadherin‐mediated Regulation of Metabolism in Oral Precancer

Cadherins are transmembrane proteins traditionally known to have a structural role in cellular adhesion. These proteins display tissue-specific changes in expression that have been correlated with poor prognosis in a variety of cancers. N-cadherin expression specifically has been associated with poor oral cancer prognosis. An estimated 80% of oral cancers exhibit aberrant N-cadherin expression. We have previously shown that cadherins can alter growth factor receptor signaling cascades, which have been shown in other studies to direct metabolic changes essential to oral cancer metastasis. The goal of the current study was to characterize the mechanism(s) by which abnormal expression of N-cadherin may alter metabolic activity in oral epithelia. We have utilized a dysplastic oral keratinocyte (DOK) line to develop retrovirally-transduced cells which express control levels or reduced levels of N-cadherin protein. Using these lines, we evaluated the effect of N-cadherin expression on EGF-dependent EGFR phosphorylation as well as downstream effectors within the mammalian target of rapamycin (mTOR) signaling pathway. Western blot analysis of our EGF-treated DOK lines suggested that N-cadherin expression suppressed phosphorylation of EGFR at Tyr 1068, which plays a role in EGFR degradation, and Tyr 1045, which can mediate cell survival through activation of signal transducer and activator of transcription 3 (STAT3). We also found minimal changes in phosphorylation of Tyr 992, a phosphosite associated with mitogenic signaling. EGFR activation has been shown to direct metabolism through phosphatidyl inositol-3 kinase (PI3K)/Akt/mTOR signaling. Our data indicated that N-cadherin expression is necessary for maximal EGF-directed phosphorylation of both Akt at Ser 473 and of mTORC1 at Ser 2448. mTOR has been shown to increase synthesis of the transcription factor hypoxia inducible factor-1 alpha (HIF-1 alpha) to redirect glycolytic intermediates from oxidative metabolism to anaerobic glycolysis by way of lactate dehydrogenase (LDH), a hallmark of the Warburg effect. We found that N-cadherin expression suppressed HIF-1 alpha synthesis but did not appear to alter lactate dehydrogenase expression. It is important to note that reduced expression of N-cadherin did not alter levels of either E- or P-cadherin expression. Taken together, these findings suggest a role for N-cadherin in the regulation of mTOR-related metabolic signaling, and in modulation of the Warburg effect in oral precancer. Given the high incidence of N-cadherin expression in oral cancer as well as its correlation with poor prognosis, elucidating the mechanisms by which N-cadherin regulates metabolism could reveal novel and promising targets for future therapeutic approaches.

Metabonomic Profiling Analyses Reveal ANS Upregulation to Enhance the Flavonoid Pathway of Purple-Fleshed Sweet Potato Storage Root in Response to Deep Shading

Intercropping, as a common worldwide cultivation pattern, provides opportunities for sustainable agriculture with fuller use of light, temperature and land resources and greater yield per unit of land. The intercropping impact on crop quality is a current focus. This study found that shading cultivation of purple-fleshed sweet potato can improve the storage root pigment accumulation by more than 20% to increase economic benefits. We performed gas chromatography and mass spectrometry analysis of storage roots of the anthocyanin-enriched cultivar Jihei-1 under 60% shading and nonshaded treatments. A total of 224 differential metabolites were identified, among which N-acetyl-5-hydroxytryptamine, 1-monopalmitin, 4-pyridoxic acid, dodecano, arbutin, tryptophan, citrulline and phenylalanine were significantly upregulated under shading with a more than 10-fold change. Furthermore, metabolic pathway enrichment maps were based on the biological processes and stratification level selected. These metabolites mainly influenced the pathways of phenylpropanoid biosynthesis, the citrate cycle, organic acid biosynthesis and metabolism and amino acid metabolism. Through tissue-specific dynamic changes in amino acids, soluble sugars, starch and anthocyanins during storage root development, we proposed a variety-specific strategy of purple-fleshed sweet potato in response to prolonged deep shading, that is, utilizing and enhancing broad aboveground-tissue photosynthesis and transferring photosynthates into roots in advance, leading to a rapid increase in storage root anthocyanin synthesis. With comprehensive qPCR, western blot and enzyme activity analyses, we identified three key enzymes, CHS, ANS and 3GT, in purple-fleshed sweet potato storage roots in response to shading, which affect the root anthocyanin content by influencing the flavonoid metabolism pathway. This study provides a theoretical basis for revealing the regulation of anthocyanin synthesis in crops and a guidance for high-quality sweet potato cultivation and nutritional improvement using shade facilities.

Comprehensive RNA-Seq Profiling Reveals Temporal and Tissue-Specific Changes in Gene Expression in Sprague-Dawley Rats as Response to Heat Stress Challenges.

Understanding heat stress physiology and identifying reliable biomarkers are paramount for developing effective management and mitigation strategies. However, little is known about the molecular mechanisms underlying thermal tolerance in animals. In an experimental model of Sprague–Dawley rats subjected to temperatures of 22 ± 1°C (control group; CT) and 42°C for 30 min (H30), 60 min (H60), and 120 min (H120), RNA-sequencing (RNA-Seq) assays were performed for blood (CT and H120), liver (CT, H30, H60, and H120), and adrenal glands (CT, H30, H60, and H120). A total of 53, 1,310, and 1,501 differentially expressed genes (DEGs) were significantly identified in the blood (P < 0.05 and |fold change (FC)| >2), liver (P < 0.01, false discovery rate (FDR)–adjusted P = 0.05 and |FC| >2) and adrenal glands (P < 0.01, FDR-adjusted P = 0.05 and |FC| >2), respectively. Of these, four DEGs, namely Junb, P4ha1, Chordc1, and RT1-Bb, were shared among the three tissues in CT vs. H120 comparison. Functional enrichment analyses of the DEGs identified in the blood (CT vs. H120) revealed 12 biological processes (BPs) and 25 metabolic pathways significantly enriched (FDR = 0.05). In the liver, 133 BPs and three metabolic pathways were significantly detected by comparing CT vs. H30, H60, and H120. Furthermore, 237 BPs were significantly (FDR = 0.05) enriched in the adrenal glands, and no shared metabolic pathways were detected among the different heat-stressed groups of rats. Five and four expression patterns (P < 0.05) were uncovered by 73 and 91 shared DEGs in the liver and adrenal glands, respectively, over the different comparisons. Among these, 69 and 73 genes, respectively, were proposed as candidates for regulating heat stress response in rats. Finally, together with genome-wide association study (GWAS) results in cattle and phenome-wide association studies (PheWAS) analysis in humans, five genes (Slco1b2, Clu, Arntl, Fads1, and Npas2) were considered as being associated with heat stress response across mammal species. The datasets and findings of this study will contribute to a better understanding of heat stress response in mammals and to the development of effective approaches to mitigate heat stress response in livestock through breeding.

Characterization of spontaneous facet joint osteoarthritis

Purpose: Although rodent models of traumatically or chemically induced spinal facet joint osteoarthritis (FJOA) were previously described, animal models of typical spontaneous FJOA haven’t been documented. This study aimed to identify the characteristics of murine spontaneous FJOA and its molecular mechanisms. Methods: The lumbar facet joints of mice bearing mutant NFAT1 alleles and of wild-type (WT, control) mice were examined by histopathology, quantitative gene expression, immunohistochemistry, and histomorphometry using a novel FJOA scoring system at 2, 6, 12, and 18 months of age. The reproducibility of the FJOA scoring system was confirmed by inter-observer and intra-observer variability tests. Tissue-specific histomorphometric and gene expression changes were statistically analyzed. Results: NFAT1-mutant facet joints displayed dysfunction of articular chondrocytes and synovial cells with aberrant gene and protein expression in cartilage and synovium as early as 2 months. osteoarthritic structural changes such as articular surface destruction and chondro-osteophyte formation became evident in NFAT1-mutant facet joints at 6 months. Severe FJOA changes including deeper cartilage loss, synovial thickening, separation of cartilage from thickened subchondral bone, as well as tissue-specific molecular and cellular alterations were evident in NFAT1-mutant mice at 12 and 18 months. OA-like structural changes were not detected in WT facet joints at any ages, though aging-related cartilage degeneration was observed at 18 months. Conclusions: This study characterized a novel murine model of spontaneous FJOA and developed the first FJOA scoring system. The age- and tissue-specific molecular and cellular characteristics in the NFAT1-mutant facet joints have provided new insights into the pathogenetic mechanisms for initiation and progression of spontaneous FJOA.

Severe Spinal Cord Injury in Rats Induces Chronic Changes in the Spinal Cord and Cerebral Cortex Metabolism, Adjusted by Thiamine That Improves Locomotor Performance.

Our study aims at developing knowledge-based strategies minimizing chronic changes in the brain after severe spinal cord injury (SCI). The SCI-induced long-term metabolic alterations and their reactivity to treatments shortly after the injury are characterized in rats. Eight weeks after severe SCI, significant mitochondrial lesions outside the injured area are demonstrated in the spinal cord and cerebral cortex. Among the six tested enzymes essential for the TCA cycle and amino acid metabolism, mitochondrial 2-oxoglutarate dehydrogenase complex (OGDHC) is the most affected one. SCI downregulates this complex by 90% in the spinal cord and 30% in the cerebral cortex. This is associated with the tissue-specific changes in other enzymes of the OGDHC network. Single administrations of a pro-activator (thiamine, or vitamin B1, 1.2 mmol/kg) or a synthetic pro-inhibitor (triethyl glutaryl phosphonate, TEGP, 0.02 mmol/kg) of OGDHC within 15–20 h after SCI are tested as protective strategies. The biochemical and physiological assessments 8 weeks after SCI reveal that thiamine, but not TEGP, alleviates the SCI-induced perturbations in the rat brain metabolism, accompanied by the decreased expression of (acetyl)p53, increased expression of sirtuin 5 and an 18% improvement in the locomotor recovery. Treatment of the non-operated rats with the OGDHC pro-inhibitor TEGP increases the p53 acetylation in the brain, approaching the brain metabolic profiles to those after SCI. Our data testify to an important contribution of the OGDHC regulation to the chronic consequences of SCI and their control by p53 and sirtuin 5.

BCAA Supplementation in Mice with Diet-induced Obesity Alters the Metabolome Without Impairing Glucose Homeostasis.

Circulating branched chain amino acid (BCAA) levels are elevated in obese humans and genetically obese rodents. However, the relationship of BCAAs to insulin resistance in diet-induced obese mice, a commonly used model to study glucose homeostasis, is still ill-defined. Here we examined how high-fat high-sucrose (HFHS) or high-fat diet (HFD) feeding, with or without BCAA supplementation in water, alters the metabolome in serum/plasma and tissues in mice and whether raising circulating BCAA levels worsens insulin resistance and glucose intolerance. Neither HFHS nor HFD feeding raised circulating BCAA levels in insulin-resistant diet-induced obese mice. BCAA supplementation raised circulating BCAA and branched-chain α-keto acid levels and C5-OH/C3-DC acylcarnitines (AC) in muscle from mice fed an HFHS diet or HFD, but did not worsen insulin resistance. A set of short- and long-chain acyl CoAs were elevated by diet alone in muscle, liver, and white adipose tissue (WAT), but not increased further by BCAA supplementation. HFD feeding reduced valine and leucine oxidation in WAT but not in muscle. BCAA supplementation markedly increased valine oxidation in muscle from HFD-fed mice, while leucine oxidation was unaffected by diet or BCAA treatment. Here we establish an extensive metabolome database showing tissue-specific changes in mice on 2 different HFDs, with or without BCAA supplementation. We conclude that mildly elevating circulating BCAAs and a subset of ACs by BCAA supplementation does not worsen insulin resistance or glucose tolerance in mice. This work highlights major differences in the effects of BCAAs on glucose homeostasis in diet-induced obese mice versus data reported in obese rats and in humans.