Transgenic Research Articles

Transgenic rabbits with genes of human granulocyte colony-stimulating factor and green fluorescent protein

Human granulocyte–colony stimulating factor (GCSF) is one of the pharmacological proteins that can be isolated from the milk of transgenic (TG) animals. The plasmid containing the human GCSF gene under the control of regulatory elements of the bovine β-lactoglobulin gene and the reporter green fluorescent protein (EGFP) gene under the cytomegalovirus (cmv) promoter were obtained. The use of the selected promoters ensures tissue-specific expression of the target protein in the mammary gland of the TG producing animal and a high level of early expression of the reporter protein in eukaryotic cells, which makes it possible to detect TG embryos at the cultivation stage and perform their preimplantation selection. Testing of the gene construct effectiveness was carried out on TG rabbits obtained by microinjection into the male pronucleus of zygotes. It was concluded that GFP is toxic to embryos in the early stages of development due to overexpression of the EGFP gene under a strong cmv promoter. The TG female rabbit (F0) was obtained, in which the level of human GKSF in milk and blood serum was assessed by the ELISA method. Of the 22 baby rabbits obtained from her in four kindling, two were transgenic. Offspring (F1) was obtained from the TG male F0, 56 % of which were males, of which 88 % were TG and did not differ from ordinary rabbits in terms of health. Among females, TG was 10 %, and they died within two weeks after birth.

Mendelian Randomization Reveals Potential Causal Relationships Between DNA Damage Repair-Related Genes and Inflammatory Bowel Disease.

DNA damage repair (DDR) plays a key role in maintaining genomic stability and developing inflammatory bowel disease (IBD). However, no report about the causal association between DDR and IBD exists. Whether DDR-related genes are the precise causal association to IBD in etiology remains unclear. Herein, we employed a multi-omics summary data-based Mendelian randomization (SMR) approach to ascertain the potential causal effects of DDR-related genes in IBD. Methods: Summary statistics from expression quantitative trait loci (eQTL), DNA methylation QTL (mQTL), and protein QTL (pQTL) on European descent were included. The GWAS summarized data for IBD and its two subtypes, Crohn's disease (CD) and ulcerative colitis (UC), were acquired from the FinnGen study. We elected from genetic variants located within or near 2000 DDR-related genes in cis, which are closely associated with DDR-related gene changes. Variants were selected as instrumental variables (IVs) and assessed for causality with IBD and its subtypes using both SMR and two-sample MR (TSMR) approaches. Colocalization analysis was employed to evaluate whether a single genetic variant simultaneously influences two traits, thereby validating the pleiotropy hypothesis. Results: We identified seven DDR-related genes (Arid5b, Cox5a, Erbb2, Ube2l3, Gpx1, H2bcl2, and Mapk3), 33 DNA methylation genes, and two DDR-related proteins (CD274 and FCGR2A) which were all causally associated with IBD and its subtypes. Beyond causality, we integrated the multi-omics data between mQTL-eQTL and conducted druggability values. We found that DNA methylation of Erbb2 and Gpx1 significantly impacted their gene expression levels offering insights into the potential regulatory mechanisms of risk variants on IBD. Meanwhile, CD247 and FCGR2A could serve as targets for potential pharmacological interventions in IBD. Conclusions: Our study demonstrates the causal role of DDR in IBD based on the data-driven MR. Moreover, we found potential regulatory mechanisms of risk variants on IBD and potential pharmacological targets.

MiR-199a-3p mitigates simulated microgravity-induced cardiac remodeling by targeting MEF2C.

Microgravity-induced cardiac remodeling and dysfunction present significant challenges to long-term spaceflight, highlighting the urgent need to elucidate the underlying molecular mechanisms and develop precise countermeasures. Previous studies have outlined the important role of miRNAs in cardiovascular disease progression, with miR-199a-3p playing a crucial role in myocardial injury repair and the maintenance of cardiac function. However, the specific role and expression pattern of miR-199a-3p in microgravity-induced cardiac remodeling remain unclear. We separately utilized mouse tail suspension and rhesus monkey bedrest models to construct simulated microgravity conditions and observed significant cardiac remodeling and dysfunction in both species, accompanied by a marked downregulation of miR-199a-3p expression in their hearts. By generating cardiac-specific transgenic (TG) mice and subjecting them to tail suspension, we observed that the wild-type (WT) mice exhibited cardiac remodeling characterized by increased fibrosis, smaller cardiomyocytes, and reduced ejection fraction (EF). In contrast, the miR-199a-3p TG mice were able to counteract the cardiac remodeling induced by tail suspension, demonstrating that miR-199a-3p can protect against simulated microgravity-induced cardiac remodeling. Subsequently, we employed an AAV9-mediated delivery system for cardiac-specific overexpression of miR-199a-3p, significantly mitigating cardiac remodeling and dysfunction induced by simulated microgravity. Mechanistically, miR-199a-3p targets MEF2C, inhibiting its activation induced by simulated microgravity, thereby suppressing the associated cardiac remodeling. This research identifies miR-199a-3p as a promising therapeutic target with significant potential for precise protection against spaceflight-induced cardiovascular dysfunction.

Temporal RAGE Over-Expression Disrupts Lung Development by Modulating Apoptotic Signaling.

Receptors for advanced glycation end products (RAGE) are multiligand cell surface receptors found most abundantly in lung tissue. This study sought to evaluate the role of RAGE in lung development by using a transgenic (TG) mouse model that spatially and temporally controlled RAGE overexpression. Histological imaging revealed that RAGE upregulation from embryonic day (E) 15.5 to E18.5 led to a thickened alveolar parenchyma and reduced alveolar surface area, while RAGE overexpression from E0 to E18.5 caused a significant loss of tissue and decreased architecture. Mitochondrial dysfunction was a hallmark of RAGE-mediated disruption, with decreased levels of anti-apoptotic BCL-W and elevated pro-apoptotic BID, SMAC, and HTRA2, indicating compromised mitochondrial integrity and increased intrinsic apoptotic activity. Extrinsic apoptotic signaling was similarly dysregulated, as evidenced by the increased expression of TNFRSF21, Fas/FasL, and Trail R2 in E0-18.5 RAGE TG mice. Additionally, reductions in IGFBP-3 and IGFBP-4, coupled with elevated p53 and decreased p27 expression, highlighted disruptions in the cell survival and cycle regulatory pathways. Despite the compensatory upregulation of inhibitors of apoptosis proteins (cIAP-2, XIAP, and Survivin), tissue loss and structural damage persisted. These findings underscore RAGE's role as a pivotal modulator of lung development. Specifically, the timing of RAGE upregulation significantly impacts lung development by influencing pathways that cause distinct histological phenotypes. This research may foreshadow how RAGE signaling plausibly contributes to developmental lung diseases.

Synergistic effects of tRNA modification defects in Escherichia coli K12.

tRNAs are the central adaptor molecule in translation and require a wide variety of post-transcriptional modifications to fulfill their functions. The model gram-negative Escherichia coli K-12 is one of the handfuls of bacteria where all the tRNA modifications and corresponding genes have been characterized. This work dissects epistatic relationships between tRNA modification genes in E. coli by conducting a synthetic lethal screen revealing 5 pairs of modifications that cannot be deleted in combination when cells are grown in rich media, and 15 pairs of modifications that lead to growth defects when deleted in combination. The truA gene involved in the insertion of Psi residues at positions 38 to 40 in multiple tRNAs gave the highest number of synthetic lethality phenotypes that could be complemented by the expression of the truA gene in trans and in some cases suppressed by the overexpression of target tRNAs. A pilot phenotype screen of strains lacking two tRNA modifications genes viable in rich media lead to the identification of growth conditions that exhibited poor growth. This work lays the foundation to dissect the role of modifications in tRNA quality control.

Mitochondrial Alterations in Alzheimer's Disease: Insight from the 5xFAD Mouse Model.

Mitochondrial dysfunction is increasingly recognized as a key factor in Alzheimer's disease (AD) pathogenesis, but the precise relationship between mitochondrial dynamics and proteinopathies in AD remains unclear. This study investigates the role of mitochondrial dynamics and function in the hippocampal tissue and peripheral blood mononuclear cells (PBMCs) of 5xFAD transgenic mice, as a model of AD. The levels of mitochondrial fusion proteins OPA1 and MFN2 and fission proteins DRP1 and phospho-DRP1 (S616) at 3, 6, and 9months of age were assessed. Western blot analysis revealed significantly lower levels of OPA1 and MFN2 in the hippocampus of 6- and 9-month-old transgenic (TG) 5xFAD mice compared to controls (CTR), while DRP1 and pDRP1 levels were increased in 9-month-old TG mice. Additionally, MFN2 were decreased inthe PBMCs of 9-month-old TGmice,indicatingsystemic mitochondrial alterations. Ultrastructural analysis of hippocampal tissues showed substantial alterations in mitochondrial morphology, including abnormalities in size and shape, a preponderance of teardrop-shaped mitochondria, and alterations in the somatic mitochondria-ER complex. Notably,mitochondria-associated ER contact sites were more distant in TG mice, suggesting functional impairments. Flow cytometric measurements demonstrated decreased mitochondrial membrane potential and mass, along with increased superoxide production, in the PBMCs of TG mice, particularly at 9months, highlighting compromised mitochondrial function. Levels of keymitochondrial proteins including VDAC, TOM2O, and mitophagy-related protein PINK1 levels altered in both central andperipheral tissue of TG mice. These findings suggest that mitochondrial dysfunction and altered dynamics are early events in AD development in 5xFAD mice, manifesting in both central and peripheral tissues, and support the notion that mitochondrial abnormalities are an integral component of AD pathology. These insights might lead to the development of targeted therapies that modulate mitochondrial dynamics and function to mitigate AD progression.

Exploring Microtubule Dynamics in Alzheimer's Disease: Longitudinal Assessment Using [11C]MPC‐6827 PET Imaging in APP/PS1 and PS301S Mouse Models

AbstractBackgroundBrains affected by Alzheimer's disease (AD) exhibit senile plaques containing amyloid beta (Aβ) peptides and neurofibrillary tangles, formed when tau becomes hyperphosphorylated and disengages from microtubules (MTs). Early instability in MTs is observed in the AD process, emphasizing its significance in connecting the hallmark pathologies of Aβ/tau‐based degenerative events. While current Aβ and tau PET approaches can characterize disease lesions, they fall short in capturing earlier molecular events. MT‐PET aims to address this gap by targeting these early events, providing crucial insights into AD pathophysiology. The PET radiotracer, [11C]MPC‐6827, capable of tracking and quantifying MT‐based changes in real‐time and in vivo, addresses an urgent unmet need and facilitates the monitoring of MT changes in the early stages of AD. Here we present for the first time a comprehensive longitudinal PET imaging study of [11C]MPC‐6827 in Aβ‐overexpressing (APP/PS1) and tau‐overexpressing (P301S) mouse models of AD.MethodsLongitudinal [11C]MPC‐6827 PET imaging, biodistribution studies, autoradiography, and behavioral assessments were conducted at multiple time points in APP/PS1 (3 to 22 mo old) and P301S (3 to 13‐mo‐old ) transgenic (TG) and age‐matched wild‐type (WT) mice (n=7/group). Whole‐brain standard uptake values for PET, %injected dose/gram for biodistribution, specific brain uptake for autoradiography, and nesting weight for cognitive assessments were determined and PET correlations for TG mice at different age‐points were calculated.ResultsLongitudinal PET imaging demonstrated a 1.3‐fold (***p<0.0001) and 0.9‐fold (**p<0.005) higher brain uptake in APP/PS1 TG mice from 3 to 22 mo and P301S TG mice from 3 to 13 mo respectively (Figure 1) and uptake increased with increasing Aβ and tau loads in AD brains. Longitudinal PET data positively correlated with biodistribution (Pearson r=0.94), and autoradiography results (r=0.55) and negatively correlated with cognitive data (r=‐0.65) in APP/PS1 mice (Figure 2).ConclusionIncreased [11C]MPC‐6827 brain PET uptake with both increasing Aβ and tau depositions longitudinally in AD brains (along with corroborating biodistribution and autoradiography results) clearly demonstrate the role of early MT dysregulations in Aβ and tau‐based neurodegeneration processes. These findings highlight the potential of [11C]MPC‐6827 PET as a powerful tool for monitoring MT disintegration early‐on. Ongoing experiments are exploring translational potential in humans.

Liver-gut axis signaling regulates circadian energy metabolism in shift workers.

Circadian rhythm is critical to maintaining the whole-body metabolic homeostasis of an organism. Chronic disruption of circadian rhythm by shift work is an important risk factor for metabolic diseases. Fibroblast growth factor 15/19 (FGF15/19), a key component in the liver-gut axis, potently suppresses bile acid (BA) synthesis and improves insulin sensitivity. FGF15/19 emerges as a novel pharmaceutical target for prevention and treatment of metabolic diseases. The nicotinamide adenine dinucleotide (NAD+)-dependent sirtuin 1 (SIRT1) deacetylase plays an important role in the maintenance of hepatic homeostasis by linking hepatic metabolism to circadian rhythm. Here, our clinical study identified that circadian rhythmicity and levels of plasma FGF19 and BA profiling, and cellular NAD+-dependent SIRT1 signaling were disturbed in night shift (NS, n = 10) compared to day shift (DS, n = 12) nurses. Our invitro data showed that recombinant FGF19 protein rescued cellular circadian rhythm disrupted by SIRT1 inhibitors. Furthermore, we determined the effect of FGF15 on circadian rhythm and hepatic metabolism in wild-type (WT), Fgf15 knockout (KO), and Fgf15 transgenic (TG) mice. The expressions of circadian-controlled genes (CCGs) involved in SIRT1 signaling, BA and lipid metabolism, and inflammation were disrupted in Fgf15 KO compared to WT and/or Fgf15 TG mice. Moreover, systemic FGF15 deficiency led to the circadian disturbance of NAD+-dependent SIRT1 signaling and significant reduction during nighttime in mice. These findings suggest that FGF15/19 regulates the circadian energy metabolism, which warrants further studies as a putative prognostic biomarker and pharmaceutical target for preventing against metabolic diseases associated with chronic shift work.

A fungal sRNA silences a host plant transcription factor to promote arbuscular mycorrhizal symbiosis

Summary Cross‐kingdom RNA interference (ckRNAi) is a mechanism of interspecies communication where small RNAs (sRNAs) are transported from one organism to another; these sRNAs silence target genes in trans by loading into host AGO proteins. In this work, we investigated the occurrence of ckRNAi in Arbuscular Mycorrhizal Symbiosis (AMS). We used an in silico prediction analysis to identify a sRNA (Rir2216) from the AM fungus Rhizophagus irregularis and its putative plant gene target, the Medicago truncatula MtWRKY69 transcription factor. Heterologous co‐expression assays in Nicotiana benthamiana, 5′ RACE reactions and AGO1‐immunoprecipitation assays from mycorrhizal roots were used to characterize the Rir2216–MtWRKY69 interaction. We further analyzed MtWRKY69 expression profile and the contribution of constitutive and conditional MtWRKY69 expression to AMS. We show that Rir2216 is loaded into an AGO1 silencing complex from the host plant M. truncatula, leading to cleavage of a host target transcript encoding for the MtWRKY69 transcription factor. MtWRKY69 is specifically downregulated in arbusculated cells in mycorrhizal roots and increased levels of MtWRKY69 expression led to a reduced AM colonization level. Our results indicate that MtWRKY69 silencing, mediated by a fungal sRNA, is relevant for AMS; we thus present the first experimental evidence of fungus to plant ckRNAi in AMS.

Abstract 4118993: β1 Adrenergic Receptor Autoantibodies Promote Heart Failure Though Activation of Prostaglandin E2 Receptor EP1/Phosphodiesterase 4B Pathway

Background: β1 adrenergic receptor (β1-AR) autoantibodies (β1-AA) can cause heart failure (HF) through activating of β1-AR; However, β-AR antagonists cannot completely reverse the cardiac injury induced by β1-AA and improve the survival rate of patients with β1-AA-positive HF. However, the β1-AR-independent mechanisms of heart failure induced by β1-AA are unclear. Methods: Proteomics of mice hearts was used to identify the specific changed proteins induced by β1-AA. The expression of phosphodiesterase 4B (PDE4B) was detected by western blot in neonatal mice mouse cardiomyocytes (NMCMs) and heart tissues. The binding proteins with β1-AA were enriched by immunoprecipitation (IP) and identified by mass spectrum. The interaction between β1-AA and prostaglandin E2 Receptor EP1 was detected by co-IP and surface plasmon resonance. The cardiac function and cardiac remodeling of PDE4B transgenic (TG) mice and EP1 knockout (KO) mice. Results: Firstly, PDE4B was changed the most proteins induced by β1-AA compared to β1 adrenergic receptor dobutamine. Moreover, the decrease of PDE4B induced by β1-AA cannot be reversed by metoprolol in vivo and in vitro. Secondly, the cAMP/PKA pathway and cardiac injury/dysfunction induced by β1-AA were inhibited after activation of PDE4B or PDE4B-TG in vivo and in vitro. Thirdly, β1-AA can bind with EP1 and activate Gq/IP3 pathway. The activation effect was abolished by EP1 antagonist. Lastly, blocked EP1 or EP1-KO will reverse the decreased PDE4B and cardiac injury/dysfunction induced by β1-AA. Conclusions: Our work reveals that β1-AA can activate of EP1/PDE4B pathway to result in heart failure.

An abdominal obesity missense variant in the adipocyte thermogenesis gene TBX15 is implicated in adaptation to cold in Finns.

Mechanisms of abdominal obesity GWAS variants have remained largely unknown. To elucidate these mechanisms, we leveraged subcutaneous adipose tissue (SAT) single nucleus RNA-sequencing and genomics data. After discovering that heritability of abdominal obesity is enriched in adipocytes, we focused on a SAT unique adipocyte marker gene, the transcription factor TBX15, and its abdominal obesity-associated deleterious missense variant, rs10494217. The allele frequency of rs10494217 revealed a north-to-south decreasing gradient, with consistent significant FST values observed for 25 different populations when compared to Finns, a population with a history of genetic isolation. Given the role of Tbx15 in mouse thermogenesis, the frequency may have increased as an adaptation to cold in Finns. Our selection analysis provided significant evidence of selection for the abdominal obesity risk allele T of rs10494217 in Finns, with a north-to-south decreasing trend in other populations, and demonstrated that latitude significantly predicts the allele frequency. We also discovered that the risk allele status significantly affects SAT adipocyte expression of multiple adipocyte marker genes in trans in two cohorts. Two of these trans genes have been connected to thermogenesis, supporting the thermogenic effect of the TBX15 missense variant as a possible cause of its selection. Adipose expression of one trans gene, a lncRNA, AC002066.1, was strongly associated withadipocyte size, implicating it in metabolically unhealthy adipocyte hypertrophy. In summary, the abdominal obesity variant rs10494217 was selected in Finns, and individuals with the risk allele have trans effects on adipocyte expression of genes relating to thermogenesis and adipocyte hypertrophy.

Phosphate overload via the type III Na-dependent Pi transporter represses aortic wall elastic fiber formation.

Phosphate (Pi) induces differentiation of arterial smooth muscle cells to the osteoblastic phenotype by inducing the type III Na-dependent Pi transporter Pit-1/solute carrier family member 1. This induction can contribute to arterial calcification, but precisely how Pi stress acts on the vascular wall remains unclear. We investigated the role of extracellular Pi in inducing microstructural changes in the arterial wall. Aortae of Pit-1-overexpressing transgenic (TG) rats and their wild-type (WT) littermates were obtained at 8 weeks after birth. The thoracic descending aorta from WT and TG rats was used for the measurement of wall thickness and uniaxial tensile testing. Structural and ultrastructural analyses were performed using light microscopy and transmission electron microscopy. Gene expression of connective tissue components in the aorta was quantified by quantitative real-time polymerase chain reaction. Aortic wall thickness in TG rats was the same as that in WT rats. Uniaxial tensile testing showed that the circumferential breaking stress in TG rats was significantly lower than that in WT rats (p<0.05), although the longitudinal breaking stress, breaking strain, and elastic moduli in both directions in TG rats were unchanged. Transmission electron microscopy analysis of the aorta from TG rats showed damaged formation of elastic fibers in the aortic wall. Fibrillin-1 gene expression levels in the aorta were significantly lower in TG rats than in WT rats (p<0.05). Pi overload acting via the arterial wall Pit-1 transporter weakens circumferential strength by causing elastic fiber malformation, probably via decreased fibrillin-1 expression.

Serotonin-2B receptor (5-HT2BR) expression and binding in the brain of APPswe/PS1dE9 transgenic mice and in Alzheimer’s disease brain tissue

Despite well-documented dysregulation in central serotonergic signaling in Alzheimer’s disease (AD), knowledge about the potential involvement of the serotonin-2B receptor (5-HT2BR) subtype remains sparse. Here, we assessed the levels of 5-HT2BRs in brain tissue from APPswe/PS1dE9 transgenic (TG) mice, AD patients, and adult microglial cells. 5-HT2BR mRNA was measured by RT-qPCR in ageing TG and wild-type (WT) mice, in samples from the middle frontal gyrus of female, AD and control subjects, and in microglia from the cerebral cortex of WT mice. The density of 5-HT2BRs was measured by autoradiography using [3H]RS 127445. Both mouse and human brains had low levels of 5-HT2BR mRNA. In whole-brain mouse samples, mRNA expression was significantly lower in TG mice compared to WT at > 18 months of age. In the Aβ-plaque-burdened neocortex and hippocampus of old TG mice, however, levels of 5-HT2BR mRNA were two-fold higher over control, with similar elevations observed in the Aβ-plaque-burdened frontal cortex of human AD patients. 5-HT2BR mRNA expression varied widely in adult microglia and was higher compared to other cortical cell subtypes. In mice, specific [3H]RS-127445 binding in the cortex was first detected after 3 months of age. The density of 5-HT2BRs was low and overall reduced in TG, compared to WT mice. Binding was detectable but too low to be reliably quantified in the human cortex. Our results document Aβ-associated increases in 5-HT2BR mRNA expression and suggest reduced receptor binding in the context of AD. Studies investigating the functional involvement of microglial 5-HT2BRs in AD are considered relevant.

Stabilizing selection and adaptation shape cis and trans gene expression variation in C. elegans.

An outstanding question in the evolution of gene expression is the relative influence of neutral processes versus natural selection, including adaptive change driven by directional selection as well as stabilizing selection, which may include compensatory dynamics. These forces shape patterns of gene expression variation within and between species, including the regulatory mechanisms governing expression in cis and trans. In this study, we interrogate intraspecific gene expression variation among seven wild C. elegans strains, with varying degrees of genomic divergence from the reference strain N2, leveraging this system's unique advantages to comprehensively evaluate gene expression evolution. By capturing allele-specific and between-strain changes in expression, we characterize the regulatory architecture and inheritance mode of gene expression variation within C. elegans and assess their relationship to nucleotide diversity, genome evolutionary history, gene essentiality, and other biological factors. We conclude that stabilizing selection is a dominant influence in maintaining expression phenotypes within the species, and the discovery that genes with higher overall expression tend to exhibit fewer expression differences supports this conclusion, as do widespread instances of cis differences compensated in trans. Moreover, analyses of human expression data replicate our finding that higher expression genes have less variable expression. We also observe evidence for directional selection driving expression divergence, and that expression divergence accelerates with increasing genomic divergence. To provide community access to the data from this first analysis of allele-specific expression in C. elegans, we introduce an interactive web application, where users can submit gene-specific queries to view expression, regulatory pattern, inheritance mode, and other information: https://wildworm.biosci.gatech.edu/ase/.

Identification of tauopathy-associated lipid signatures in Alzheimer’s disease mouse brain using label-free chemical imaging

There is cumulative evidence that lipid metabolism plays a key role in the pathogenesis of various neurodegenerative disorders including Alzheimer’s disease (AD). Visualising lipid content in a non-destructive label-free manner can aid in elucidating the AD phenotypes towards a better understanding of the disease. In this study, we combined multiple optical molecular-specific methods, Fourier transform infrared (FTIR) spectroscopic imaging, synchrotron radiation-infrared (SR-IR) microscopy, Raman and stimulated Raman scattering (SRS) microscopy, and optical-photothermal infrared (O-PTIR) microscopy with multivariate data analysis, to investigate the biochemistry of brain hippocampus in situ using a mouse model of tauopathy (rTg4510). We observed a significant difference in the morphology and lipid content between transgenic (TG) and wild type (WT) samples. Immunohistochemical staining revealed some degree of microglia co-localisation with elevated lipids in the brain. These results provide new evidence of tauopathy-related dysfunction in a preclinical study at a subcellular level.

Gene regulatory network inference from CRISPR perturbations in primary CD4+ T cells elucidates the genomic basis of immune disease

The effects of genetic variation on complex traits act mainly through changes in gene regulation. Although many genetic variants have been linked to target genes in cis, the trans-regulatory cascade mediating their effects remains largely uncharacterized. Mapping trans-regulators based on natural genetic variation has been challenging due to small effects, but experimental perturbations offer a complementary approach. Using CRISPR, we knocked out 84 genes in primary CD4+ Tcells, targeting inborn error of immunity (IEI) disease transcription factors (TFs) and TFs without immune disease association. We developed a novel gene network inference method called linear latent causal Bayes (LLCB) to estimate the network from perturbation data and observed 211 regulatory connections between genes. We characterized programs affected by the TFs, which we associated with immune genome-wide association study (GWAS) genes, finding that JAK-STAT family members are regulated by KMT2A, an epigenetic regulator. These analyses reveal the trans-regulatory cascades linking GWAS genes to signaling pathways.

Hypercorticosteronemia induces hyperphagia and obesity in human growth hormone transgenic rats

Hyperphagia and subsequent obesity are important public health issues due to the associated risks of developing serious diseases. Certain stressors play a major role in the development of hyperphagia. In previous studies, we established a line of human growth hormone transgenic (TG) rats that exhibit hyperphagia and obesity from a young age. We recently demonstrated that voluntary running on a running wheel alleviates hyperphagia in TG rats. Wheel running provides environmental enrichment for rodents and plays a role in relieving stress. These results suggested that stress is the major factor inducing hyperphagia in TG rats. Thus, in the present study, we evaluated activation of the hypothalamus–pituitary–adrenal axis. TG rats showed bilateral enlargement of adrenal glands and hypercorticosteronemia, although their hypothalamic CRH level was comparable to that of wild-type (WT) rats. The ACTH-immunoreactive area was larger and the serum ACTH level in the dark phase was higher in TG rats than in WT rats. Adrenalectomy reduced the food intake of TG rats to a level comparable to that in WT rats, and supplying glucocorticoids recurred hyperphagia in TG rats. These treatments did not affect the food intake of WT rats. Rearing TG rats under group housing prevented hyperphagia and hypercorticosteronemia. These results suggest that glucocorticoids are appetite stimulants, and that TG rats exhibit increased sensitivity to the appetite-stimulating effect of glucocorticoids.

Deficiency of SLC26A3 promotes jejunal barrier damage in metabolic disease-susceptible transgenic pigs

Intestinal disorders are common in metabolic syndrome. However, their pathogenesis is still not fully understood. Pig and human intestines are highly similar in terms of associated metabolic processes. Here, we successfully constructed a metabolic disease-susceptible transgenic (TG) Bama pig model by knocking in three humanized disease risk genes with the CRISPR/Cas9 technique to assess its potential as a model for human intestinal diseases and explore the possible pathological mechanisms involved. We found that jejunal barrier integrity was disrupted and that the infiltration of inflammatory cells increased in TG pigs after high-fat and high-sucrose diet (HFHSD) treatment. We revealed significant differences in the transcriptome, associated microbiome profiles and microbial metabolite short-chain fatty acid (SCFA) content of the jejunum of TG pigs. Notably, we found that SLC26A3 was significantly downregulated in TG pigs. Knockdown or overexpression of the SLC26A3 gene in IPEC-J2 cells significantly affected the expression of MUC2, MUC13 and occludin. Furthermore, in vitro experiments further verified that CDX2 directly regulated the expression of SLC26A3. Mechanistically, CDX2 mediated intestinal barrier function by enhancing the expression of SLC26A3 by binding to its promoter region between −1120 and − 1070 bp. TG pigs represent a promising model that provides new insights into preclinical research on human intestinal metabolic diseases associated with metabolic disorders and revealed that SLC26A3 may be a potential therapeutic target for intestinal metabolic diseases.

Cardiomyopathy characterizing and heart failure risk predicting by echocardiography and pathoanatomy in aged male mice.

Correlation between echocardiographic and pathoanatomic variables and their prognostic value in murine cardiomyopathy models remain unknown. Using echocardiography, morphometrics, and survival monitoring, we characterized transgenic (TG) mice with dilated cardiomyopathy due to cardiac overexpression of β2-adrenoceptors focusing on predicting heart failure (HF) risk and HF mortality. In 12-month-old non-TG and TG mice, echocardiography was performed to determine left ventricular (LV) dimensions (d), wall thickness (h), and fractional shortening (FS). Animals were monitored for 3 months for survival. Organ weights and pathological events indicating left HF were determined. TG mice (n = 76) had reduced FS and enlarged LV, and 79% died of HF or likely arrhythmias during the follow-up period while all non-TG mice (n = 26) survived. These mice with left HF also had pulmonary congestion and hypertrophy/dilatation of the right ventricle (RV). Weights of lungs, RV, and atria were intercorrelated (r = 0.79-0.83) and also negatively correlated with FS × (h/d) index (r = -0.502 to -0.609). By FS × (h/d) tertiles, TG mice of low tertiles were identified with the highest mortality (96%) largely due to HF (76%). In conclusion, in aged cardiomyopathy mice a good correlation existed between echocardiographic and pathoanatomic variables. Echocardiography-derived LV function and remodeling were useful in identifying a subgroup of TG mice with a high risk of HF and HF fatality.

LRRK2G2019S Gene Mutation Causes Skeletal Muscle Impairment in Animal Model of Parkinson's Disease.

While the gradually aggravated motor and non-motor disorders of Parkinson's disease (PD) lead to progressive disability and frequent falling, skeletal muscle impairment may contribute to this condition. The leucine-rich repeat kinase2 (LRRK2) is a common disease-causing gene in PD. Little is known about its role in skeletal muscle impairment and its underlying mechanisms. To investigate whether the mutation in LRRK2 causes skeletal muscle impairment, we used 3-month-old (3mo) and 14-month-old (14mo) LRRK2G2019S transgenic (TG) mice as a model of PD, compared with the age-matched littermate wild-type (WT) controls. We measured the muscle mass and strength, ultrastructure, inflammatory infiltration, mitochondrial morphology and dynamics dysfunction through behavioural analysis, electromyography (EMG), immunostaining, transmission electron microscopy (TEM) and other molecular biology techniques. The 3mo-TG mice display mild skeletal muscle impairment with spontaneous potentials in EMG (increased by 130%, p < 0.05), myofibre necrosis(p < 0.05) and myosin heavy chain-II changes (reduced by 19%, p < 0.01). The inflammatory cells and macrophage infiltration are significantly increased (CD8a+ and CD68+ cells up 1060% and 579%, respectively, both p < 0.0001) compared with the WT mice. All of the above pathogenic processes are aggravated by aging. The 14mo-TG mice EMG examinations show a reduced duration (by 31%, p < 0.01) and increased polyphasic waves of motor unit action potentials (by 28%, p < 0.05). The 14mo-TG mice present motor behavioural deficits (p < 0.05), muscle strength and mass reduction by 37% and 8% (p < 0.05 and p < 0.01, respectively). A remarkable increase in inflammatory infiltration is accompanied by pro-inflammatory cytokines in the skeletal muscles. TEM analysis shows muscle fibre regeneration with the reduced length of sarcomeres (by 6%;p < 0.05). The muscle regeneration is activated as Pax7+ cells increased by 106% (p < 0.0001), andmyoblast determination protein elevated by 71% (p < 0.01). We also document the morphological changes and dynamics dysfunction of mitochondria with the increase of mitofusin1 by 43% (p < 0.05)and voltage-dependent anion channel 1 by 115% (p < 0.001) in the skeletal muscles of 14mo-TG mice. Taken together, these findings may provide new insights into the clinical and pathogenic involvement of LRRK2G2019 mutation in muscles, suggesting that the diseases may affect not only midbrain dopaminergic neurons, but also other tissues, and it may help overall clinical management of this devastating disease.