Mouse Cells Research Articles

SATB1 prevents immune cell infiltration by regulating chromatin organization and gene expression of a chemokine gene cluster in T cells

SATB1, a key regulator of T cell development, governs lineage-specific transcriptional programs upon T cell activation. The absence of SATB1 has been linked to the initiation and progression of autoimmunity. However, its precise roles in this process remain incompletely understood. Here we show that conditional knockout of Satb1 in CD4+ T cells in mice led to T cell hyperactivation and inflammatory cell infiltration across multiple organs. Transcriptional profiling on activated T cells revealed that the loss of SATB1 led to aberrant upregulation of CC chemokines. Treating Satb1 conditional knockout mice with CC chemokine receptor inhibitor alleviated inflammatory cell infiltration. Intriguingly, SATB1’s transcriptional regulation of chemokine genes could not be attributed to its direct binding to chemokine promoters. Instead, SATB1 exerted its regulatory effects by controlling higher-order chromatin organization at a CC chemokine locus. The loss of SATB1 led to the emergence of a new chromatin domain encompassing the Ccl3, Ccl4, Ccl5, Ccl6, and Ccl9 genes and a distal enhancer, resulting in increased contacts between the enhancer and all five chemokine genes, thus inducing their upregulation. Collectively, these results demonstrate that SATB1 protects organs from immune cell infiltration by regulating chemokine expression, providing valuable insights into the development of autoimmunity-related phenotypes.

Trp53 Deletion Promotes Exacerbated Colitis, Facilitates Lgr5+ Cancer Stem Cell Expansion, and Fuels Tumorigenesis in AOM/DSS-Induced Colorectal Cancer

Colorectal cancer CRC remains one of the leading causes of cancer-related deaths worldwide, with chronic intestinal inflammation identified as a major risk factor. Notably, the tumor suppressor TP53 undergoes mutation at higher rates and earlier stages during human inflammation-driven colon tumorigenesis than in sporadic cases. We investigated whether deleting Trp53 affects inflammation-induced tumor growth and the expression of Lgr5+ cancer stem cells in mice. We examined azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colon tumorigenesis in wild-type Trp53 (+/+), heterozygous (+/−), and knockout (−/−) mice. Trp53−/− mice showed increased sensitivity to DSS colitis and earlier accelerated tumorigenesis with 100% incidence. All groups could develop invasive tumors, but knockouts displayed the most aggressive features. Unlike wild-type CRC, knockouts selectively showed increased populations of Lgr5+ colon cancer stem-like cells. Trp53 loss also boosted laminin, possibly facilitating the disruption of the tumor border. This study highlights how Trp53 deletion promotes the perfect storm of inflammation and stemness, driving colon cancer progression. Trp53 deletion dramatically shortened AOM/DSS latency and improved tumor induction efficiency, offering an excellent inflammation-driven CRC model.

Spatial microniches of IL-2 combine with IL-10 to drive lung migratory TH2 cells in response to inhaled allergen.

The mechanisms that guide T helper 2 (TH2) cell differentiation in barrier tissues are unclear. Here we describe the molecular pathways driving allergen-specific TH2 cells using temporal, spatial and single-cell transcriptomic tracking of house dust mite-specific T cells in mice. Differentiation and migration of lung allergen-specific TH2 cells requires early expression of the transcriptional repressor Blimp-1. Loss of Blimp-1 during priming in the lymph node ablated the formation of TH2 cells in the lung, indicating early Blimp-1 promotes TH2 cells with migratory capability. IL-2/STAT5 signals and autocrine/paracrine IL-10 from house dust mite-specific T cells were essential for Blimp-1 and subsequent GATA3 upregulation through repression of Bcl6 and Bach2. Spatial microniches of IL-2 in the lymph node supported the earliest Blimp-1+TH2 cells, demonstrating lymph node localization is a driver of TH2 initiation. Our findings identify an early requirement for IL-2-mediated spatial microniches that integrate with allergen-driven IL-10 from responding T cells to drive allergic asthma.

Deletion of platelet-derived growth factor receptor β suppresses tumorigenesis in metabolic dysfunction-associated steatohepatitis (MASH) mice with diabetes

The platelet-derived growth factor (PDGF) family contributes to the progression of steatohepatitis; however, changes in and the characteristics of isoform-specific expression remain unclear. Since diabetes is a major driver of metabolic dysfunction-associated steatohepatitis (MASH), we characterized the mouse model of diabetic MASH (dMASH) by focusing on PDGF signaling. Pdgfa-d expression was markedly higher in hepatic stellate cells among flow-sorted cells in control mice and also increased in dMASH. In contrast, a reanalysis of human single-cell RNA-Seq data showed the distinct distribution of each PDGF isoform with disease progression. Furthermore, inflammation and fibrosis in the liver were less severe in diabetic MASH using tamoxifen-induced PDGF receptor β (PDGFRβ)-deficient mice (KO) than in control dMASH using floxed mice (FL) at 12 weeks old. Despite the absence of tumors, the expression of tumor-related genes was lower in KO than in FL. Tumorigenesis was significantly lower in 20-week-old KO. An Ingenuity Pathway Analysis of differentially expressed miRNA between FL and KO identified functional networks associated with hepatotoxicity and cancer. Therefore, PDGFRβ signals play important roles in the progression of steatohepatitis and tumorigenesis in MASH, with the modulation of miRNA expression posited as a potential underlying mechanism.

M6A modification of mutant huntingtin RNA promotes the biogenesis of pathogenic huntingtin transcripts.

In Huntington's disease (HD), aberrant processing of huntingtin (HTT) mRNA produces HTT1a transcripts that encode the pathogenic HTT exon 1 protein. The mechanisms behind HTT1a production are not fully understood. Considering the role of m6A in RNA processing and splicing, we investigated its involvement in HTT1a generation. Here, we show that m6A methylation is increased before the cryptic poly(A) sites (IpA1 and IpA2) within the huntingtin RNA in the striatum of Hdh+/Q111 mice and human HD samples. We further assessed m6A's role in mutant Htt mRNA processing by pharmacological inhibition and knockdown of METTL3, as well as targeted demethylation of Htt intron 1 using a dCas13-ALKBH5 system in HD mouse cells. Our data reveal that Htt1a transcript levels are regulated by both METTL3 and the methylation status of Htt intron 1. They also show that m6A methylation in intron 1 depends on expanded CAG repeats. Our findings highlight a potential role for m6A in aberrant splicing of Htt mRNA.

Real-Time Imaging Assessment of Stress-Induced Vascular Inflammation Using Heartbeat-Synchronized Motion Compensation.

Chronic mental stress accelerates atherosclerosis through complicated neuroimmune pathways, needing for advanced imaging techniques to delineate underlying cellular mechanisms. While histopathology, ex vivo imaging, and snapshots of in vivo images offer promising evidence, they lack the ability to capture real-time visualization of blood cell dynamics within pulsatile arteries in longitudinal studies. An electrically tunable lens was implemented in intravital optical microscopy, synchronizing the focal plane with heartbeats to follow artery movements. ApoE-/- mice underwent 2 weeks of restraint stress before baseline imaging followed by 2 weeks of stress exposure in the longitudinal imaging, while nonstressed mice remained undisturbed. The progression of vascular inflammation was assessed in the carotid arteries through intravital imaging and histological analyses. A 4-fold reduction of motion artifact, assessed by interframe SD, and an effective temporal resolution of 25.2 Hz were achieved in beating murine carotid arteries. Longitudinal intravital imaging showed chronic stress led to a 6.09-fold (P=0.017) increase in myeloid cell infiltration compared with nonstressed mice. After 3 weeks, we observed that chronic stress intensified vascular inflammation, increasing adhered myeloid cells by 2.45-fold (P=0.031), while no significant changes were noted in nonstressed mice. Microcirculation imaging revealed increased circulating, rolling, and adhered cells in stressed mice's venules. Histological analysis of the carotid arteries confirmed the in vivo findings that stress augmented plaque area, myeloid cell and macrophage accumulation, and necrotic core volume while reducing fibrous cap thickness indicating accelerated plaque formation. We visualized the 3-dimensional structure of the carotid artery and 4-dimensional dynamics of the venules in the cremaster muscle. Dynamic focusing motion compensation intravital microscopy enabled subcellular resolution in vivo imaging of blood cell dynamics in beating arteries under chronic restraint stress in real time. This novel technique emphasizes the importance of advanced in vivo imaging for understanding cardiovascular disease.

Design and construction of a GAP-43 reporter system for potential identification of effective therapeutics for peripheral nerve regeneration

Background: Peripheral nerve injury (PNI) is a condition that can result in muscle paralysis and sensory disturbances. Electrical stimulation and/or the application of exogenous neurotrophic factors and cytokines are effective at enhancing nerve regeneration and is mediated via the expression of regeneration associated genes (RAGs) such as the growth associated protein GAP-43. Therapeutic upregulation of GAP-43 has potential use as a treatment for improving recovery from PNI. Few studies have investigated the potential of increasing GAP-43 for PNI therapeutic purposes and current methods for measuring GAP-43 expression are limited. Aims and Objectives: The broader aim of this work was to construct a motor neuron-like cell model with a GAP-43 reporter system. Such a model would have potential use in screening for novel therapeutics that upregulate GAP-43 and in the optimisation of electrical stimulation treatment in combination with these therapies. The key aim of the work was to design and construct a Cas9 expressing plasmid bearing a gRNA that targets GAP-43 cleavage and a donor plasmid bearing a reporter GFP or Neo cassette flanked with 5’ and 3’ GAP-43 homology arms (HAs) to facilitate the insertion of the reporter immediately 3’ of the GAP-43 promoter via CRISPR/Cas9 homology directed repair (HDR). Such an insertion would enable quantitative measurement of endogenous expression of the GAP-43 gene. Methods and Results: To guide the Cas9 nuclease to the target location, GAP-43 gRNA oligomers were designed and cloned downstream of the U6 promoter in the Cas9 expression plasmid px330, which also expresses the Cas9 gene and the cloned gRNA when transfected into cells. For CRISPR/Cas9 HDR, the 5’ and 3’ GAP-43 HAs were amplified from mouse genomic DNA and cloned into the donor plasmid using Gibson Assembly so that they flanked the reporter cassette. Results: This work successfully constructed the Cas9 gRNA expressing plasmid to target cleavage of the GAP-43 gene in mouse cell lines and has provided the complete design and construction foundation for generation of the reporter system for the endogenous GAP-43 gene in mice.

The Immune Regulatory Functions in B Cells Are Restored by CpG to Reduce Experimental Food Allergy.

Dysfunctional immune regulation contributes to the pathogenesis of food allergy (FA). The mechanism behind regulatory B-cell dysfunction is unclear. CpG has immune regulatory functions. The purpose of this study is to use CpG to recover the immune suppressive functions of B cells in mice with FA. An FA mouse model was created using ovalbumin as the specific antigen. Flow cytometry was used to isolate B cells from the intestinal tissues. The immune regulatory functions of B cells were assessed using immunological approaches. The results showed that the FA response was linked to low IL-10 levels in gut lavage fluids of FA mice. FA mouse intestinal B cells produced lower amounts of IL-10 as compared with B cells isolated from naïve control mice. Impaired immune suppressive functions were observed in B cells isolated from the FA mouse intestine. The inducibility of the Il10 expression in naïve B cells of the intestine of FA mice was defective. The induction of Il10 expression in FA B cells could be restored by CpG through regulating the methylation status of the Cmip promoter. CpG promoted the therapeutic efficacy of allergen specific immunotherapy by restoring the induction of IL-10+ B cells in the intestine. The expression of Il10 in B cells of the FA mouse intestine was impaired. Administration of CpG could restore the expression of Il10 in B cells in the intestine and promote immunotherapy for FA.

One-shot entorhinal maps enable flexible navigation in novel environments.

Animals must navigate changing environments to find food, shelter or mates. In mammals, grid cells in the medial entorhinal cortex construct a neural spatial map of the external environment1-5. However, how grid cell firing patterns rapidly adapt to novel or changing environmental features on a timescale relevant to behaviour remains unknown. Here, by recording over 15,000 grid cells in mice navigating virtual environments, we tracked the real-time state of the grid cell network. This allowed us to observe and predict how altering environmental features influenced grid cell firing patterns on a nearly instantaneous timescale. We found evidence that visual landmarks provide inputs to fixed points in the grid cell network. This resulted in stable grid cell firing patterns in novel and altered environments after a single exposure. Fixed visual landmark inputs also influenced the grid cell network such that altering landmarks induced distortions in grid cell firing patterns. Such distortions could be predicted by a computational model with a fixed landmark to grid cell network architecture. Finally, a medial entorhinal cortex-dependent task revealed that although grid cell firing patterns are distorted by landmark changes, behaviour can adapt via a downstream region implementing behavioural timescale synaptic plasticity6. Overall, our findings reveal how the navigational system of the brain constructs spatial maps that balance rapidity and accuracy. Fixed connections between landmarks and grid cells enable the brain to quickly generate stable spatial maps, essential for navigation in novel or changing environments. Conversely, plasticity in regions downstream from grid cells allows the spatial maps of the brain to more accurately mirror the external spatial environment. More generally, these findings raise the possibility of a broader neural principle: by allocating fixed and plastic connectivity across different networks, the brain can solve problems requiring both rapidity and representational accuracy.

Single-cell analysis reveals alternations between the aged and young mice prostates

BackgroundAging of the male prostate is an inevitable process in which the prostate undergoes hyperplasia, and this growth may lead to compression of the urethra, resulting in voiding dysfunction and associated symptoms, and an increased risk of prostate cancer. Despite the significance of prostate aging, the molecular mechanisms involved are still not fully understood.MethodsProstate split by lobes from young (2 months) and aged (24 months) mice were collected for single-cell RNA sequencing (scRNA-seq) analysis. Tissues from both anterior prostate (AP) and ventral/dorsal/lateral prostate (VDLP) were included in the study. Data analysis included unsupervised clustering using the uniform manifold approximation and projection (UMAP) algorithm to identify distinct cell types based on marker gene expression. Differential gene expression analysis was performed to identify age-related changes in gene expression across different cell types. Functional enrichment analysis was conducted to elucidate biological pathways associated with differentially expressed genes. Additionally, cellular interactions and developmental trajectories were analyzed to characterize cellular dynamics during prostate aging.ResultsThe single-cell transcriptome analysis of the mouse prostate during aging revealed heterogeneity across various cell types and their changes during the aging process. We found a significant increase in the proportion of mesenchymal and immune cells in aged mice. Our study unveiled alterations in genes and pathways associated with cellular senescence, oxidative stress, and regeneration in epithelial cells. Furthermore, we observed that basal cells may undergo epithelial-mesenchymal transition (EMT) to become mesenchymal cells, particularly prominent in aged mice. Additionally, immune cells, notably macrophages and T cells, exhibited a heightened inflammatory response in aged mice.ConclusionIn summary, our study provides a comparative analysis of the single-cell transcriptome of the aged and young mice prostates, elucidating cellular and molecular changes between the aged and young mice prostates.

Riluzole Enhancing anti-PD-1 Efficacy by Activating cGAS/STING Signaling in Colorectal Cancer.

Colorectal cancer is the second leading cause of cancer mortality in the US. Although immune checkpoint blockade therapies including anti-PD-1/PD-L1 have been successful in treating a subset of colorectal cancer patients, response rates remain low. We have found that riluzole, a well-tolerated FDA-approved oral medicine for treating amyotrophic lateral sclerosis, increased intratumoral CD8+ T cells and suppressed tumor growth of colon cancer cells in syngeneic immune competent mice. Riluzole-mediated tumor suppression was dependent on the presence of CD8+ T cells. Riluzole activates the cytosolic DNA sensing cGAS/STING pathway in colon cancer cells, resulting in increased expression of interferon β (IFNβ) and IFNβ-regulated genes including CXCL10. Inhibition of ATM, but not ATR, resulted in a synergistic increase in IFNβ expression, suggesting that riluzole induces ATM-mediated damage response that contribute to cGAS/STING activation. Depletion of cGAS or STING significantly attenuated riluzole-induced expression of IFNβ and CXCL10 as well as increase of intratumoral CD8+ T cells and suppression of tumor growth. These results indicate that riluzole-mediated tumor infiltration of CD8+ T cells and attenuation of tumor growth is dependent on tumor cell intrinsic STING activation. To determine whether riluzole treatment primes the tumor microenvironment for immune checkpoint modulation, riluzole was combined with anti-PD-1 treatment. This combination showed greater efficacy than either single agent, and strongly suppressed tumor growth in vivo. Taken together, our studies indicate that riluzole activates cGAS/STING-mediated innate immune responses, which might be exploited to sensitize colorectal tumors to anti-PD-1/PD-L1 therapies. .

Novel H-2Db-restricted CD8 epitope derived from mouse MAGE-type antigen P1A mediates antitumor immunity in C57BL/6 mice

BackgroundMelanoma antigen gene (MAGE)-type antigens are promising targets for cancer immunotherapy as they are expressed in cancer cells but not in normal tissues, except for male germline cells. The mouse...

IL-7Rα on CD4+ T cells is required for their survival and the pathogenesis of experimental autoimmune encephalomyelitis

BackgroundThe IL-7 receptor alpha (IL-7Rα) binds both IL-7 and thymic stromal lymphopoietin (TSLP). IL-7Rα is essential for the development and survival of naive CD4+ T cells and their differentiation to effector/memory CD4+ T cells. Mice lacking IL-7Rα have severe lymphopenia and are resistant to experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis. However, it has been reported that IL-7Rα on peripheral CD4+ T cells is disposable for their maintenance and EAE pathogenesis, which does not align with the body of knowledge on the role of IL-7Rα in the biology of CD4+ T cells. Given that a definitive study on this important topic is lacking, we revisited it using a novel approach, an inducible knockout of the IL-7Rα gene in CD4+ T cells.MethodsWe generated Il7rafl/fl/CD4CreERT2 double transgenic mouse line (henceforth CD4ΔIl7ra), susceptible to tamoxifen-induced knockout of the IL-7Rα gene in CD4+ T cells. CD4ΔIl7ra mice were immunized with MOG35 − 55 for EAE induction and monitored for disease development. The expression of IL-7Rα, CD4+ T cell numbers, and MOG35 − 55-specific CD4+ T cell response was evaluated in the central nervous system (CNS) and lymphoid tissues by flow cytometry. Additionally, splenocytes of CD4ΔIl7ra mice were stimulated with MOG35 − 55 to assess their proliferative response and cytokine production by T helper cells.ResultsLoss of IL-7Rα from the surface of CD4+ T cells in CD4ΔIl7ra mice was virtually complete several days after tamoxifen treatment. The loss of IL-7Rα in CD4+ T cells led to a gradual and substantial decrease in their numbers in both non-immunized and immunized CD4ΔIl7ra mice, followed by slow repopulation up to the initial numbers. CD4ΔIl7ra mice did not develop EAE. We found a decrease in the total numbers of TNF-, IFN-γ-, IL-17 A-, and GM-CSF-producing CD4+ T cells and regulatory T cells in the spleens and CNS of immunized CD4ΔIl7ra mice. Tracking MOG35 − 55-specific CD4+ T cells revealed a significant reduction in their numbers in CD4ΔIl7ra mice and decreased proliferation and cytokine production in response to MOG35 − 55.ConclusionOur study demonstrates that IL-7Rα on peripheral CD4+ T cells is essential for their maintenance, immune response, and EAE pathogenesis.

The DHODH inhibitor teriflunomide impedes cell proliferation and enhances chemosensitivity to daunorubicin (DNR) in T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological tumor that requires novel treatment strategies, especially for relapsed/refractory cases. Dihydroorotate dehydrogenase (DHODH), a key enzyme in the de novo pyrimidine synthesis pathway, has been identified as a potential target for tumors. Besides, Teriflunomide (TRF) is a DHODH inhibitor with anticancer effects; however, its role in T-ALL remains poorly understood. Here, we investigated the potential anticancer effects of TRF on T-ALL cells, and the results showed that TRF inhibited cell proliferation, caused S-phase cell cycle arrest, and promoted apoptosis of T-ALL (MOLT4 and JURKAT) cell lines. In addition, TRF reduced the infiltration capacity of T-ALL cells in T-ALL xenograft mice while up-regulating the expression of P53 and BTG2. The BTG2 knockdown significantly attenuated the inhibitory effect of TRF on cellular growth and suppressed the TRF-mediated elevated expression of P53 in T-ALL cells. Moreover, combined treatment with TRF and daunorubicin (DNR) significantly reduced cell viability and promoted apoptosis in DNR-resistant T-ALL cells. Our study provides valuable insights into the critical role of TRF in treating T-ALL while increasing the sensitivity of DNR-resistant T-ALL cells to DNR.

Curcumin Attenuates Dextran Sodium Sulfate Induced Colitis in Obese Mice.

Curcumin (Cur), with diverse pharmacological properties, shows anti-obesity, immunomodulatory, and anti-inflammatory effects. Its role in ulcerative colitis complicated by obesity remains unclear. Here, colitis is induced in obese mice using dextran sulfate sodium (DSS), followed by administration of Cur at a dosage of 100mg kg-1 for 14 days. Cur effectively alleviates DSS-induced colitis in obese mice, accompanied by an increase in body weight and survival rate, reduction in disease activity index, elongation of the colon, decrease in colonic weight, and improvements in ulcer formation and inflammatory cell infiltration in colonic tissues. Additionally, Cur effectively improves lipid metabolism and the composition of the gut microbiota, and enhances mucosal integrity and boosts anti-oxidative stress capacity in obese mice with colitis. Importantly, Cur is effective in improving the homeostasis of memory T cells in obese mice with colitis. Furthermore, Cur regulates inflammatory cytokines expression and inhibits activation of the JAK2/STAT signaling pathway in colonic tissues of obese mice with colitis. Cur alleviates colitis in obese mice through a comprehensive mechanism that improves lipid metabolism, modulates gut microbiota composition, enhances mucosal integrity and anti-oxidative stress, balances memory T cell populations, regulates inflammatory cytokines, and suppresses the JAK2/STAT signaling pathway.

Injury-induced myosin-specific tissue-resident memory T cells drive immune checkpoint inhibitor myocarditis

Cardiac myosin-specific (MyHC) T cells drive the disease pathogenesis of immune checkpoint inhibitor-associated myocarditis (ICI-myocarditis). To determine whether MyHC T cells are tissue-resident memory T (TRM) cells, we characterized cardiac TRM cells in naive mice and established that they have a distinct phenotypic and transcriptional profile that can be defined by their upregulation of CD69, PD-1, and CXCR6. We then investigated the effects of cardiac injury through a modified experimental autoimmune myocarditis mouse model and an ischemia-reperfusion injury mouse model and determined that cardiac inflammation induces the recruitment of autoreactive MyHC TRM cells, which coexpress PD-1 and CD69. To investigate whether the recruited MyHC TRM cells could increase susceptibility to ICI-myocarditis, we developed a two-hit ICI-myocarditis mouse model where cardiac injury was induced, mice were allowed to recover, and then were treated with anti-PD-1 antibodies. We determined that mice who recover from cardiac injury are more susceptible to ICI-myocarditis development. We found that murine and human TRM cells share a similar location in the heart and aggregate along the perimyocardium. We phenotyped cells obtained from pericardial fluid from patients diagnosed with dilated cardiomyopathy and ischemic cardiomyopathy and established that pericardial T cells are predominantly CD69+ TRM cells that up-regulate PD-1. Finally, we determined that human pericardial macrophages produce IL-15, which supports and maintains pericardial TRM cells.

Bergenin, the main active ingredient of Bergenia purpurascens, attenuates Th17 cell differentiation by downregulating fatty acid synthesis.

Bergenin is the main active ingredient of Bergenia purpurascens, a medicinal plant which has long been used to treat a variety of Th17 cell-related diseases in China, such as allergic airway inflammation and colitis. This study aimed to uncover the underlying mechanisms by which bergenin impedes Th17 cell response in view of cellular metabolism. Invitro, bergenin treatment reduced the frequency of Th17 cells generated from naïve CD4+ T cells of mice. Mechanistically, bergenin preferentially restrained fatty acid synthesis (FAS) but not other metabolic pathways in differentiating Th17 cells, and exogenous addition of either palmitic acid (PA) or oleic acid (OA) and combination with acetyl-CoA carboxylase 1 (ACC1) activator citric acid dampened the inhibition of bergenin on Th17 cell differentiation. Bergenin inhibited FAS through downregulating the expression of SREBP1 via restriction of histone H3K27 acetylation in the SREBP1 promoter, and SREBP1 overexpression weakened the inhibition of bergenin on Th17 differentiation. Furthermore, bergenin was shown to directly interact with SIRT1 and result in activation of SIRT1. Either combination with SIRT1 inhibitor EX527 or point mutation plasmid of SIRT1 diminished the inhibitory effect of bergenin on FAS and Th17 cell differentiation. Finally, the inhibitory effect of bergenin on Th17 cell response and SIRT1 dependence were verified in mice with dextran sulfate sodium-induced colitis. In short, bergenin repressed Th17 cell response by downregulating FAS via activation of SIRT1, which might find therapeutic use in Th17 cell-related diseases.

Distinct muscle regenerative capacity of human induced pluripotent stem cell-derived mesenchymal stromal cells in Ullrich congenital muscular dystrophy model mice

BackgroundUllrich congenital muscular dystrophy (UCMD) is caused by a deficiency in type 6 collagen (COL6) due to mutations in COL6A1, COL6A2, or COL6A3. COL6 deficiency alters the extracellular matrix structure and biomechanical properties, leading to mitochondrial defects and impaired muscle regeneration. Therefore, mesenchymal stromal cells (MSCs) that secrete COL6 have attracted attention as potential therapeutic targets. Various tissue-derived MSCs exert therapeutic effects in various diseases. However, no reports have compared the effects of MSCs of different origins on UCMD pathology.MethodsTo evaluate which MSC population has the highest therapeutic efficacy for UCMD, in vivo (transplantation of MSCs to Col6a1-KO/NSG mice) and in vitro experiments (muscle stem cell [MuSCs] co-culture with MSCs) were conducted using adipose tissue-derived MSCs, bone marrow-derived MSCs, and xeno-free-induced iPSC-derived MSCs (XF-iMSCs).ResultsIn transplantation experiments on Col6a1-KO/NSG mice, the group transplanted with XF-iMSCs showed significantly enhanced muscle fiber regeneration compared to the other groups 1 week after transplantation. At 12 weeks after transplantation, only the XF-iMSCs transplantation group showed a significantly larger muscle fiber diameter than the other groups without inducing fibrosis, which was observed in the other transplantation groups. Similarly, in co-culture experiments, XF-iMSCs were found to more effectively promote the fusion and differentiation of MuSCs derived from Col6a1-KO/NSG mice than the other primary MSCs investigated in this study. Additionally, in vitro knockdown and supplementation experiments suggested that the IGF2 secreted by XF-iMSCs promoted MuSC differentiation.ConclusionXF-iMSCs are promising candidates for promoting muscle regeneration while avoiding fibrosis, offering a safer and more effective therapeutic approach for UCMD than other potential therapies.

Transgenic overexpression of the miR-200b/200a/429 cluster prevents mammary tumor initiation in Neu/Erbb2 transgenic mice.

Although significant progress in the treatment of breast cancer has been achieved, toxic therapies would not be required if breast cancer could be prevented from developing in the first place. While breast cancer prevention is difficult to study in humans due to long disease latency and stochastic cancer development, transgenic mouse models with 100% incidence and defined mammary tumor onset, provide excellent models for tumor prevention studies. In this study, we used Neu/Erbb2 transgenic mice (MTB-TAN) as a model of human HER2+ breast cancer to investigate whether a family of microRNAs, known as the miR-200 family, can prevent mammary tumor development. Overexpression of Neu induced palpable mammary tumors in 100% of the mice within 38 days of Neu overexpression. When the miR-200b/200a/429 cluster was co-overexpressed with Neu in the same mammary epithelial cells (MTB-TANba429 mice), the miR-200b/200a/429 cluster prevented Neu from inducing mammary epithelial hyperplasia and mammary tumor development. RNA sequencing revealed alterations in the extracellular matrix of the mammary gland and a decrease in stromal cells including myoepithelial cells in Neu transgenic mice. Immunohistochemistry for smooth muscle actin confirmed that mammary epithelial cells in control and MTB-TANba429 mice were surrounded by a layer of myoepithelial cells and these myoepithelial cells were lost in MTB-TAN mice with hyperplasia. Thus, we have shown for the first time that elevated expression of miR-200 family members in mammary epithelial cells can completely prevent mammary tumor development in Neu transgenic mice possibly through regulating myoepithelial cells.

The Reindeer Circadian Clock Is Rhythmic and Temperature-compensated But Shows Evidence of Weak Coupling Between the Secondary and Core Molecular Clock Loops.

Circadian rhythms synchronize the internal physiology of animals allowing them to anticipate daily changes in their environment. Arctic habitats may diminish the selective advantages of circadian rhythmicity by relaxing daily rhythmic environmental constraints, presenting a valuable opportunity to study the evolution of circadian rhythms. In reindeer, circadian control of locomotor activity and melatonin release is weak or absent, and the molecular clockwork is reportedly non-functional. Here we present new evidence that the circadian clock in cultured reindeer fibroblasts is rhythmic and temperature-compensated. Compared with mouse fibroblasts, however, reindeer fibroblasts have a short free-running period, and temperature cycles have an atypical impact on clock gene regulation. In reindeer cells, Per2 and Bmal1 reporters show rapid responses to temperature cycles, with a disintegration of their normal antiphasic relationship. The antiphasic Per2-Bmal1 relationship re-emerges immediately after release from temperature cycles, but without complete temperature entrainment and with a marked decline in circadian amplitude. Experiments using Bmal1 promoter reporters with mutated RORE sites showed that a reindeer-like response to temperature cycles can be mimicked in mouse or human cell lines by decoupling Bmal1 reporter activity from ROR/REV-ERB-dependent transcriptional regulation. We suggest that weak coupling between core and secondary circadian feedback loops accounts for the observed behavior of reindeer fibroblasts in vitro. Our findings highlight diversity in how the thermal environment affects the temporal organization of mammals living under different thermoenergetic constraints.