Explore the vast range of titles available.

•A network analysis combined fMRI and immunohistochemistry was performed on operant learning.•Functional connectivity in limbic areas increased at early stage of training.•Functional connectivity in sensorimotor cortex increased at late stage of training.•These connectivity changes in fMRI were validated using EGR1 immunohistochemistry. Previous studies of operant learning have addressed neuronal activities and network changes in specific brain areas, such as the striatum, sensorimotor cortex, prefrontal/orbitofrontal cortices, and hippocampus. However, how changes in the whole-brain network are caused by cellular-level changes remains unclear. We, therefore, combined resting-state functional magnetic resonance imaging (rsfMRI) and whole-brain immunohistochemical analysis of early growth response 1 (EGR1), a marker of neural plasticity, to elucidate the temporal and spatial changes in functional networks and underlying cellular processes during operant learning. We used an 11.7-Tesla MRI scanner and whole-brain immunohistochemical analysis of EGR1 in mice during the early and late stages of operant learning. In the operant training, mice received a reward when they pressed left and right buttons alternately, and were punished with a bright light when they made a mistake. A group of mice (n = 22) underwent the first rsfMRI acquisition before behavioral sessions, the second acquisition after 3 training-session-days (early stage), and the third after 21 training-session-days (late stage). Another group of mice (n = 40) was subjected to histological analysis 15 min after the early or late stages of behavioral sessions. Functional connectivity increased between the limbic areas and thalamus or auditory cortex after the early stage of training, and between the motor cortex, sensory cortex, and striatum after the late stage of training. The density of EGR1-immunopositive cells in the motor and sensory cortices increased in both the early and late stages of training, whereas the density in the amygdala increased only in the early stage of training. The subcortical networks centered around the limbic areas that emerged in the early stage have been implicated in rewards, pleasures, and fears. The connectivities between the motor cortex, somatosensory cortex, and striatum that consolidated in the late stage have been implicated in motor learning. Our multimodal longitudinal study successfully revealed temporal shifts in brain regions involved in behavioral learning together with the underlying cellular-level plasticity between these regions. Our study represents a first step towards establishing a new experimental paradigm that combines rsfMRI and immunohistochemistry to link macroscopic and microscopic mechanisms involved in learning.

Background A balance between estrogen (E2) and progesterone (P4) is vital for a successful pregnancy, and an imbalance between these two hormones yields female infertility. E2 mediates uterine receptivity and regulates endometrial growth, the immune system, and hormone signaling by rapidly inducing early growth response 1 (EGR1). However, the precise mechanism by which EGR1 regulates E2-mediated uterine growth remains unclear. This study examined the transcriptional signatures of ovariectomized (OVX) Egr1 knockout (KO) mice compared to those of wild-type (WT) mice to clarify the function of EGR1 in the E2-dependent uterine response. Results Egr1 KO uteri exhibited an impaired E2 response, with significant changes in the expression of the key genes Bgn , c-Kit , Ripor2 , and Arg2 . During early E2 response, Egr1 KO uteri showed upregulated insulin-like growth factor (IGF) signaling pathway genes and downregulated reproduction-related genes. During late E2 response, Egr1 KO uteri showed enhanced proliferative processes, such as DNA replication and mitotic cell cycle phase transition, potentially related to poly-ADP ribosylation (PARylation), along with a reduction in immune response. Notably, the transcriptional signatures in mature OVX Egr1 KO uteri resembled those in immature uteri, with similar increases in proliferation and decreases in immune response at the pathway level. Conclusions Our findings indicate that EGR1 is essential for regulating immune response and uterine proliferation via IGF signaling and PARylation, and acts as a gatekeeper transcription factor that mediates E2 actions in the mature uterus. Notably, we found that the transcriptional signatures of EGR1 in mature uteri overlapped with the primary E2 function and suggested a novel concept that these transcriptional signatures in mature Egr1 KO uteri are similar to those of immature uteri. Our findings offer novel insights into the role of EGR1 as an E2 mediator in the uterus at the molecular level.

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases worldwide, characterized by intense pruritus and eczematous lesions. Aberrant expression of thymic stromal lymphopoietin (TSLP) in keratinocytes is associated with the pathogenesis of AD and is considered a therapeutic target for the treatment of this disease. Saikosaponin A (SSA) and saikosaponin C (SSC), identified from Radix Bupleuri, exert anti-inflammatory effects. However, the topical effects of SSA and SSC on chronic inflammatory skin diseases are unclear. In this study, we investigated the effects of SSA and SSC on TSLP suppression in an AD-like inflammatory environment. We observed that SSA and SSC suppressed tumor necrosis factor-α-induced TSLP expression by downregulating the expression of the transcription factor early growth response 1 (EGR1) via inhibition of the extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2, and p38 mitogen-activated protein kinase pathways. We also confirmed that topical application of SSA or SSC reduced AD-like skin lesions in BALB/c mice challenged with 2,4-dinitrochlorobenzene. Our findings suggest that suppression of EGR1-regulated TSLP expression in keratinocytes might be attributable to the anti-inflammatory effects of SSA and SSC in AD-like skin lesions.

Background LL-37 is a naturally occurring antimicrobial peptide found in the wound bed and assists wound repair. No published study has characterized the role of LL-37 in the function(s) of human mesenchymal stem cells (MSCs). This study investigated the functions of adipose-derived stromal/stem cells (ASCs) activated by LL-37 by performing both in vitro assays with cultured cells and in vivo assays with C57BL/6 mice with hair loss. Methods Human ASCs were isolated from healthy donors with written informed consent. To examine the effects of LL-37 on ASC function, cell proliferation and migration were measured by a cell counting kit (CCK-8) and a Transwell migration assay. Early growth response 1 (EGR1) mRNA expression was determined by microarray and real-time PCR analyses. The protein levels of EGR1 and regenerative factors were analyzed by specific enzyme-linked immunosorbent assays and western blotting. Results LL-37 treatment enhanced the proliferation and migration of human ASCs expressing formyl peptide receptor like-1. Microarray and real-time PCR data showed that EGR1 expression was rapidly and significantly increased by LL-37 treatment. LL-37 treatment also enhanced the production of EGR1. Moreover, small interfering RNA-mediated knockdown of EGR1 inhibited LL-37-enhanced ASC proliferation and migration. Activation of mitogen-activated protein kinases (MAPKs) was essential not only for LL-37-enhanced ASC proliferation and migration but also EGR1 expression; treatment with a specific inhibitor of extracellular signal-regulated kinase, p38, or c-Jun N-terminal kinase blocked the stimulatory effect of LL-37. EGR1 has a strong paracrine capability and can influence angiogenic factors in ASCs; therefore, we evaluated the secretion levels of vascular endothelial growth factor, thymosin beta-4, monocyte chemoattractant protein-1, and stromal cell-derived factor-1. LL-37 treatment increased the secretion of these regenerative factors. Moreover, treatment with the conditioned medium of ASCs pre-activated with LL-37 strongly promoted hair growth in vivo. Conclusions These findings show that LL-37 increases EGR1 expression and MAPK activation, and that preconditioning of ASCs with LL-37 has a strong potential to promote hair growth in vivo. This study correlates LL-37 with MSC functions (specifically those of ASCs), including cell expansion, cell migration, and paracrine actions, which may be useful in terms of implantation for tissue regeneration.

Acute kidney injury (AKI) is associated with damage to the nephrons and tubular epithelial cells (TECs), which can lead to chronic kidney disease and end-stage renal disease. Identifying new biomarkers before kidney dysfunction will offer crucial insight into preventive and therapeutic options for the treatment of AKI. Early growth response 1 (EGR1) has been found to be a pioneer transcription factor that can sequentially turn on/off key downstream genes to regulate whole-body regeneration processes in the leopard worm. Whether EGR1 modulates renal regeneration processes in AKI remains to be elucidated. AKI models of ischemia-reperfusion injury (IRI) and folic acid (FA) were developed to investigate the roles of EGR1 in kidney injury and regeneration. To further determine the function of EGR1, mice were applied. Furthermore, RNA sequencing of renal TECs, Chromatin Immunoprecipitation (ChIP) assay, and Dual-luciferase reporter assay were carried out to investigate whether EGR1 affects the expression of SOX9. EGR1 is highly expressed in the kidney after AKI both in humans and mice through analysis of the Gene Expression Omnibus (GEO) database. Furthermore, we verified that EGR1 rapidly up-regulates in the very early stage of IRI and nephrotoxic models of AKI, and validation studies confirmed the essential roles of EGR1 in renal tubular cell regeneration. Further experiments affirmed that genetic inhibition of aggravates the severity of AKI in mouse models. Furthermore, our results revealed that EGR1 could increase SOX9 expression in renal TECs by directly binding to the promoter of the gene, thus promoting SOX9 cell proliferation by activating the Wnt/β-catenin pathway. Together, our results demonstrated that rapid and transient induction of EGR1 plays a renoprotective role in AKI, which highlights the prospects of using EGR1 as a potential therapeutic target for the treatment of AKI.

Early growth response factor 1 (EGR1) is a zinc-finger transcription factor that plays a vital role in the development of hair follicles. According to our previous studies, EGR1 is a transcriptional promoter of the bone morphogenetic protein 7 (BMP7), a candidate gene involved in the proliferation of dermal papilla cells. Since hair follicles are the basis of lambskin pattern formation and dermal papilla cells (DPCs) act on hair follicle growth, in order to elucidate the role of EGR1 and hair follicles, this study aimed to investigate the biological role of EGR1 in DPCs. In our study, the EGR1 coding sequence (CDS) region was firstly cloned by polymerase chain reaction, and bioinformatics analysis was performed. Then, the function of EGR1 was detected by 5-ethynyl-2’-deoxyuridine (EDU) and Cell Counting Kit-8 (CCK8), and Western blot (WB) was conducted to analyze the cellular effect of EGR1 on DPCs. The proliferative effect of EGR1 on DPCs was also further confirmed by detecting its expression by qPCR and WB on marker genes of proliferation, including PCNA and CDK2. The sequence of the EGR1 CDS region of a lamb was successfully cloned, and its nucleic acid sequence was analyzed and found to be highly homologous to Rattus norvegicus, Mus musculus, Bos taurus and Homo sapiens. Predictive analysis of the protein encoded by EGR1 revealed that it is an extra-membrane protein, and not a secretory protein, with subcellular localization in the nucleus and cytoplasm. The proliferative effect of DPCs was significantly stronger (p < 0.01) in EGR1 up-regulated DPCs compared to the controls, while the opposite result was observed in EGR1 down-regulated DPCs. Markers of proliferation including PCNA and CDK2 also appeared to be differentially upregulated in EGR1 gene overexpression compared to the controls, with the opposite result in EGR1 gene downregulation. In summary, our study revealed that EGR1 promotes the proliferation of DPCs, and we speculate that EGR1 may be closely associated with hair follicle growth and development.

Arteriovenous fistulas (AVFs) are preferred access points for hemodialysis. The present study aimed to investigate the function of early growth response-1 (Egr-1) in the proliferation and migration of smooth muscle cells (SMCs) and assess its potential as a new therapeutic target for AVF treatment. A comprehensive analysis combining public data-source mining, human tissue collection, animal studies, cell culture experiments and various molecular biology techniques was conducted. The public dataset GSE119296 was used for immunohistochemical analyses of human AVF stenosis samples. SMC-specific Egr-1 knockout mice and various in vitro assays on primary rat vascular SMCs were used to evaluate the effect of Egr-1 on the functional capacity of SMCs. RNA sequencing and chromatin immunoprecipitation sequencing was performed. Egr-1 was upregulated in human AVF stenosis samples and cultured SMCs. Knockout of Egr-1 in mice mitigated AVF outflow tract stenosis, improved flow dynamics and diminished neointima formation. In vitro, Egr-1 ablation reduced SMC proliferation and migration; Egr-1 transcriptionally activated Egr-2. Increased Egr-1 expression facilitated SMC proliferation and migration through Egr-2 regulation, contributing to AVF stenosis. Consequently, targeting Egr-1 may offer a novel therapeutic approach for managing AVF intimal hyperplasia and improving AVF patency and function in patients with end-stage renal disease.

The mechanisms by which TCR signaling 'instructs' thymic lineages remain unclear. Bendelac and colleagues show that the TCR-induced transcription factor Egr2 specifies the early and late stages of differentiation into the natural killer T cell lineage. Interactions driven by the T cell antigen receptor (TCR) determine the lineage fate of CD4 + CD8 + thymocytes, but the molecular mechanisms that induce the lineage-determining transcription factors are unknown. Here we found that TCR-induced transcription factors Egr2 and Egr1 had higher and more-prolonged expression in precursors of the natural killer T (NKT) than in cells of conventional lineages. Chromatin immunoprecipitation followed by deep sequencing showed that Egr2 directly bound and activated the promoter of Zbtb16 , which encodes the NKT lineage–specific transcription factor PLZF. Egr2 also bound the promoter of Il2rb , which encodes the interleukin 2 (IL-2) receptor β-chain, and controlled the responsiveness to IL-15, which signals the terminal differentiation of the NKT lineage. Thus, we propose that persistent higher expression of Egr2 specifies the early and late stages of NKT lineage differentiation, providing a discriminating mechanism that enables TCR signaling to 'instruct' a thymic lineage.

Lentinan (LNT) isolated from Lentinus edodes is a vital host defense potentiator previously utilized as an adjuvant in cancer therapy. The present study investigated the effect of LNT on the mouse hepatocellular carcinoma (HCC) cell line Hepa1-6 and its possible mechanism. Mouse HCC apoptosis and its potential associated mechanism were then explored using in vitro and in vivo approaches. For in vitro approaches, the effect of LNT on the proliferation of Hepa1-6 cells was investigated by Cell Counting Kit-8 assay. Annexin V-FITC staining and flow cytometry were applied to explore HCC apoptosis. Western blotting was used to analyze related proteins, such as EGR1, phosphatase and tensin homolog (PTEN), phosphorylated protein kinase B (p-Akt), protein kinase B (Akt), B lymphocyte-2 (Bcl-2), Bcl2 family-associated X protein (Bax), etc. Cellular immunofluorescence staining was employed to assess the localization and expression of EGR1 and PTEN in nuclear and cytoplasmic fractions of Hepa1-6 cells. The association between EGR1 and PTEN was explored by EGR1 overexpression in cell lines. For in vivo methods, a mouse model of diethylnitrosamine (DEN)-induced primary liver cancer was established using C57BL/6 mice to investigate the inhibitory effect of LNT on liver cancer. Histopathology of liver tissue from mice was detected by hematoxylin-eosin staining and immunohistochemical assay. In vitro and in vivo results showed that LNT can inhibit the proliferation and promote the apoptosis of mouse HCC cells. Besides, LNT increased the expression of EGR1 in Hepa1-6 cells, which is translocated to the nucleus to function as a transcriptional factor. EGR1 then activates the expression of the tumor suppressor PTEN, thereby inhibiting the activation of the AKT signaling pathway. These data revealed a novel anti-tumor mechanism by which LNT can induce apoptosis to inhibit mouse HCC progression through the EGR1/PTEN/AKT axis. These results provide a scientific basis for the potential use of LNT in drug development and clinical applications associated with primary liver cancer.

Background The early growth response 1 (EGR1) is a central transcription factor involved in systemic sclerosis (SSc) pathogenesis. Iguratimod is a synthesized anti-rheumatic disease-modifying drug, which shows drastic inhibition to EGR1 expression in B cells. This study is aiming to investigate the anti-fibrotic effect of iguratimod in SSc. Methods EGR1 was detected by immunofluorescence staining real-time PCR or western blot. Iguratimod was applied in EGR1 overexpressed or knockdown human dermal fibroblast, bleomycin pre-treated mice, tight skin 1 mice, and SSc skin xenografts. RNA sequencing was performed in cultured fibroblast and xenografts to identify the iguratimod regulated genes. Results EGR1 overexpressed predominantly in non-immune cells of SSc patients. Iguratimod reduced EGR1 expression in fibroblasts and neutralized changes of EGR1 response genes regulated by TGFβ. The extracellular matrix (ECM) production and activation of fibroblasts were attenuated by iguratimod while EGR1 overexpression reversed this effect of iguratimod. Iguratimod ameliorated the skin fibrosis induced by bleomycin and hypodermal fibrosis in TSK-1 mice. Decreasing in the collagen content as well as the density of EGR1 or TGFβ positive fibroblasts of skin xenografts from naïve SSc patients was observed after local treatment of iguratimod. Conclusion Targeting EGR1 expression is a probable underlying mechanism for the anti-fibrotic effect of iguratimod.