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Journal of Leukocyte Biology Oct 2019Discussion of the potential contradictory effects of vitamin D receptor signaling in a mouse model of autoimmune hepatitis.
Discussion of the potential contradictory effects of vitamin D receptor signaling in a mouse model of autoimmune hepatitis.
Topics: Animals; Concanavalin A; Mice; Mice, Knockout; Receptors, Calcitriol; Vitamin D
PubMed: 31379001
DOI: 10.1002/JLB.3CE0519-157R -
Cornea Oct 2022Endothelial dysfunction is one of the leading causes of corneal blindness and one of the common indications for keratoplasty. At present, the standard of treatment... (Review)
Review
Endothelial dysfunction is one of the leading causes of corneal blindness and one of the common indications for keratoplasty. At present, the standard of treatment involves the replacement of the dysfunctional endothelium with healthy tissue taken from a donor. Because there is a paucity of healthy donor tissues, research on the corneal endothelium has focused primarily on expanding these cells in the laboratory for transplantation in an attempt to reduce the gap between the demand and supply of donor tissues for transplantation. To expand these cells, which are nonmitotic in vivo, various mitogens, substrates, culture systems, and alternate strategies have been tested with varying success. The biggest challenge has been the limited proliferative capacity of these cells compounded with endothelial to mesenchymal transition that alters the functioning of these cells and renders them unsuitable for human transplantation. This review aims to give a comprehensive overview of the most common and successful techniques used in the culture of the cells, the current available evidence in support of epithelial to mesenchymal transition (EMT), alternate sources for deriving the corneal endothelial cells, and advances made in transplantation of these cells.
Topics: Corneal Transplantation; Endothelial Cells; Endothelium, Corneal; Epithelial-Mesenchymal Transition; Humans; Mitogens
PubMed: 36107851
DOI: 10.1097/ICO.0000000000003080 -
Cellular and Molecular Gastroenterology... 2021Serotonin signaling is ubiquitous in the gastrointestinal (GI) system, where it acts as a neurotransmitter in the enteric nervous system (ENS) and influences intestinal... (Review)
Review
Serotonin signaling is ubiquitous in the gastrointestinal (GI) system, where it acts as a neurotransmitter in the enteric nervous system (ENS) and influences intestinal motility and inflammation. Since its discovery, serotonin has been linked to cellular proliferation in several types of tissues, including vascular smooth muscle, neurons, and hepatocytes. Activation of serotonin receptors on distinct cell types has been shown to induce well-known intracellular proliferation pathways. In the GI tract, potentiation of serotonin signaling results in enhanced intestinal epithelial proliferation, and decreased injury from intestinal inflammation. Furthermore, activation of the type 4 serotonin receptor on enteric neurons leads to neurogenesis and neuroprotection in the setting of intestinal injury. It is not surprising that the mitogenic properties of serotonin are pronounced within the GI tract, where enterochromaffin cells in the intestinal epithelium produce 90% of the body's serotonin; however, these proliferative effects are attributed to increased serotonin signaling within the ENS compartment as opposed to the intestinal mucosa, which are functionally and chemically separate by virtue of the distinct tryptophan hydroxylase enzyme isoforms involved in serotonin synthesis. The exact mechanism by which serotonergic neurons in the ENS lead to intestinal proliferation are not known, but the activation of muscarinic receptors on intestinal crypt cells indicate that cholinergic signaling is essential to this signaling pathway. Further understanding of serotonin's role in mucosal and enteric nervous system mitogenesis may aid in harnessing serotonin signaling for therapeutic benefit in many GI diseases, including inflammatory bowel disease, malabsorptive conditions, and cancer.
Topics: Animals; Cell Proliferation; Cell Survival; Gastrointestinal Motility; Gastrointestinal Tract; Humans; Mitogens; Receptors, Serotonin; Serotonin; Signal Transduction
PubMed: 34022423
DOI: 10.1016/j.jcmgh.2021.05.008 -
Zhonghua Gan Zang Bing Za Zhi =... Nov 2022To evaluate the potential of receptor-interacting protein 3 (RIP3) as a therapeutic target for autoimmune hepatitis (AIH). Immunofluorescence assay was used to observe...
To evaluate the potential of receptor-interacting protein 3 (RIP3) as a therapeutic target for autoimmune hepatitis (AIH). Immunofluorescence assay was used to observe the activated expression levels of RIP3 and its downstream signal mixed lineage protein kinase domain-like protein (MLKL) in the liver tissues of patients with AIH and hepatic cyst. Concanavalin A (ConA) was injected into the tail vein to induce acute immune-mediated hepatitis in mice. Intervention was performed by intraperitoneal injection of RIP3 inhibitor GSK872 or solvent carrier. Peripheral blood and liver tissues were collected. Serum transaminases level, qPCR and flow cytometry were analyzed. The intergroup comparison was performed with an independent sample -test. The expression level of p-RIP3 (the activated forms of RIP3) and phosphorylated p-MLKL (MLKL after phosphorylation) downstream signal were significantly higher in the liver tissue of AIH patients than those of controls. Compared with the control group, the expression levels of RIP3 and MLKL mRNA were significantly increased in the liver tissue of AIH patients (relative expression levels 3.28±0.29 . 0.98±0.09, 4.55±0.51 . 1.06±0.11), and the differences were statistically significant (=6.71 and 6.77, respectively, and <0.01). The expression levels of RIP3 and MLKL mRNA were significantly higher in the mice liver tissue of ConA-induced immune hepatitis than those in the control group (relative expression levels 2.35±0.09 . 0.89±0.11,2.77±0.22 . 0.73±0.16,=10.4,6.33, <0.01). RIP3 inhibitor GSK872 had significantly attenuated ConA-induced immune liver injury and inhibited the expression of tumor necrosis factor-α, interleukin-6, interleukin-1β and NLRP3 in liver. Compared with the control group, the proportions of CD45F4/80 macrophages, CD4 IL-17 Th17 cells, CD4 CD25 regulatory T (Treg) cells and CD11b Gr-1 myeloid derived suppressor cells (MDSCs) were significantly increased in the liver of ConA + Vehicle group. Compared with ConA + Vehicle group, the proportion of CD45F4/80 macrophages and CD4 IL-17 Th17 cells were significantly decreased, while the proportion of CD4 CD25Treg cells and CD11b Gr-1 MDSCs with immunomodulatory functions were significantly increased in mice liver of ConA+GSK872 group. AIH patients and ConA-induced immune hepatitis mice have activated RIP3 signal in liver tissues. Inhibition of RIP3 reduces the expression and proportion of proinflammatory factors and cells, and promotes the accumulation of CD4 CD25 Treg cells and CD11b Gr-1 MDSCs with immunomodulatory functions in the liver of mice with immune hepatitis, thereby alleviating liver inflammation and injury. Therefore, the inhibition of RIP3 is expected to be a new approach for the treatment of AIH.
Topics: Animals; Humans; Mice; Concanavalin A; Hepatitis, Autoimmune; Interleukin-17; Liver; RNA, Messenger; T-Lymphocytes, Regulatory; Receptor-Interacting Protein Serine-Threonine Kinases
PubMed: 36891703
DOI: 10.3760/cma.j.cn501113-20200819-00466 -
Immunologic Research Feb 2023The proliferation of antigen-specific lymphocyte clones, the initial step in acquired immunity, is vital for effector functions. Proliferation tests both in immunology... (Comparative Study)
Comparative Study
The proliferation of antigen-specific lymphocyte clones, the initial step in acquired immunity, is vital for effector functions. Proliferation tests both in immunology research and diagnosis are gaining attendance gradually, while the use of adult healthy individuals as controls of pediatric patients is a question. This study aimed to investigate and compare mitogen-stimulated proliferation responses of total lymphocytes and T- and B-lymphocyte subsets in adult and children healthy donors. Nineteen children and 20 adult healthy donors were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) purified from peripheral blood samples of the donors, by Ficoll gradient centrifugation, were stained with CFSE and were cultured in a 37 ℃ CO incubator for 120 h with the absence or existence of polyclonal activators: PHA and CD-Mix. After cell culture, PBMCs were stained with monoclonal antibodies against CD4 and CD19, and proliferation percentages of CD4 T and CD19 B cells, together with total lymphocytes were determined by flow cytometry. This study revealed similarities between children and adult age groups, concerning mitogenic stimulation of the lymphocytes. The only difference was a significantly high proliferation of pediatric CD4 T cells in response to PHA. CD4 T cell responses against PHA were inversely correlated with altering age. When pediatric individuals were distributed into age groups of 0-2 years, 3-5 years, and 6-18 years, PHA responses of CD4 cells were found to be diminished with advancing age. These findings propose the possibility of enrollment of adult healthy individuals as controls for pediatric patients.
Topics: Adult; Child; Child, Preschool; Humans; Infant; Infant, Newborn; CD4-Positive T-Lymphocytes; Cell Proliferation; Flow Cytometry; Leukocytes, Mononuclear; Lymphocyte Activation; Mitogens; Adolescent
PubMed: 36261686
DOI: 10.1007/s12026-022-09328-2 -
Veterinary Immunology and... May 2020CellTrace Violet™ is a commonly used fluorescent dye used with flow cytometry to identify cell proliferation. Activated equine lymphocytes were examined using flow...
CellTrace Violet™ is a commonly used fluorescent dye used with flow cytometry to identify cell proliferation. Activated equine lymphocytes were examined using flow cytometry, microscopy and tritiated thymidine proliferation assays. CellTrace Violet™ was incorporated into the equine lymphocytes effectively. Equine lymphocytes proliferated when activated with pokeweed mitogen, but did not proliferate when previously stained with CellTrace Violet™. Serial dilutions of CellTrace Violet™ did not eliminate the inhibition of activated lymphocytes. Equine lymphocyte viability was greater than 90 % for both stained and unstained cells. Based on these data, CellTrace Violet™ is not recommended for the assessment of lymphocyte proliferation in equine cells. The mechanism of inhibition of equine lymphocyte proliferation by CellTrace Violet™ is unknown.
Topics: Animals; Cell Proliferation; Cell Survival; Concanavalin A; Flow Cytometry; Fluorescent Dyes; Horses; Lymphocyte Activation; Lymphocytes; Pokeweed Mitogens
PubMed: 32229340
DOI: 10.1016/j.vetimm.2020.110037 -
Genes & Genetic Systems Jun 2022Continuity of spermatogenesis in mammals is underpinned by spermatogenic (also called spermatogonial) stem cells (SSCs) that self-renew and differentiate into sperm that... (Review)
Review
Continuity of spermatogenesis in mammals is underpinned by spermatogenic (also called spermatogonial) stem cells (SSCs) that self-renew and differentiate into sperm that pass on genetic information to the next generation. Despite the fundamental role of SSCs, the mechanisms underlying SSC homeostasis are only partly understood. During homeostasis, the stem cell pool remains constant while differentiating cells are continually produced to replenish the lost differentiated cells. One of the outstanding questions here is how self-renewal and differentiation of SSCs are balanced to achieve a constant self-renewing pool. In this review, we shed light on the regulatory mechanism of SSC homeostasis, with focus on the recently proposed mitogen competition model in a facultative (or open) niche microenvironment.
Topics: Adult Germline Stem Cells; Animals; Cell Differentiation; Homeostasis; Intercellular Signaling Peptides and Proteins; Male; Mammals; Mitogens; Spermatogenesis; Spermatogonia; Stem Cells
PubMed: 35125370
DOI: 10.1266/ggs.21-00062 -
Free Radical Biology & Medicine Jan 2024The pathogenesis of Autoimmune Hepatitis (AIH) is closely associated with perturbations in iron ion metabolism, during which Stimulator of Interferon Genes (STING) plays...
The pathogenesis of Autoimmune Hepatitis (AIH) is closely associated with perturbations in iron ion metabolism, during which Stimulator of Interferon Genes (STING) plays an important role. However, the precise regulatory mechanism remains elusive. In this study, we investigated the relationship between iron dysregulation and STING activation in Concanavalin A (ConA)-induced AIH liver injury. STING knockout (STING) mice and AAV (Adeno-Associated virus)-Sting1-RNAi-treated mice were involved and subjected in AIH. We observed that increased iron dysregulation was linked with STING activation, but this effect was effectively reversed by the administration of iron chelating agent Desferoxamine (DFO) and the antioxidant Ferrostatin-1 (Fer-1). Notably, the iron transport protein Transferrin (TF) and Transferrin Receptor (TfR) exhibited significant accumulation in AIH along with upregulated expression of ferritin protein. Additionally, the deficiency of STING reduced hepatic iron accumulation, mitigated oxidative stress, and attenuated macrophage activation during ConA treatment. Furthermore, liver-specific knockdown of STING using AAV-Sting1-RNAi significantly ameliorated liver iron dysregulation and oxidative stress response induced by Kupffer cells (KCs). KC-derived STING exacerbates liver damage severity in AIH through promoting disturbances in hepatic iron ion metabolism as well as oxidative stress response. These findings provide valuable insights into the pathogenesis of AIH and may pave the way for potential therapeutic strategies targeting STING and iron metabolism in the future.
Topics: Animals; Mice; Concanavalin A; Hepatitis, Autoimmune; Inflammation; Kupffer Cells; Liver
PubMed: 38052276
DOI: 10.1016/j.freeradbiomed.2023.11.038 -
Protein and Peptide Letters 2023The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune... (Review)
Review
BACKGROUND
The immune system is able to recognize substances that originate from inside or outside the body and are potentially harmful. Foreign substances that bind to immune system components exhibit antigenicity and are defined as antigens. The antigens exhibiting immunogenicity can induce innate or adaptive immune responses and give rise to humoral or cell-mediated immunity. The antigens exhibiting mitogenicity can cross-link cell membrane receptors on B and T lymphocytes leading to cell proliferation. All antigens vary greatly in physicochemical features such as biochemical nature, structural complexity, molecular size, foreignness, solubility, and so on.
OBJECTIVE
Thus, this review aims to describe the molecular bases of protein-antigenicity and those molecular bases that lead to an immune response, lymphocyte proliferation, or unresponsiveness.
CONCLUSION
The epitopes of an antigen are located in surface areas; they are about 880-3,300 Da in size. They are protein, carbohydrate, or lipid in nature. Soluble antigens are smaller than 1 nm and are endocytosed less efficiently than particulate antigens. The more the structural complexity of an antigen increases, the more the antigenicity increases due to the number and variety of epitopes. The smallest immunogens are about 4,000-10,000 Da in size. The more phylogenetically distant immunogens are from the immunogen-recipient, the more immunogenicity increases. Antigens that are immunogens can trigger an innate or adaptive immune response. The innate response is induced by antigens that are pathogen-associated molecular patterns. Exogenous antigens, T Dependent or T Independent, induce humoral immunogenicity. TD protein-antigens require two epitopes, one sequential and one conformational to induce antibodies, whereas, TI non-protein-antigens require only one conformational epitope to induce low-affinity antibodies. Endogenous protein antigens require only one sequential epitope to induce cell-mediated immunogenicity.
Topics: Epitopes; T-Lymphocytes; Carrier Proteins; Cell Membrane
PubMed: 37691216
DOI: 10.2174/0929866530666230907093339 -
Chinese Medical Journal Jun 2022Sepsis, a serious condition with high mortality, usually causes sepsis associated encephalopathy (SAE) that involves neuronal cell death. However, the cell death...
A new cell death program regulated by toll-like receptor 9 through p38 mitogen-activated protein kinase signaling pathway in a neonatal rat model with sepsis associated encephalopathy.
BACKGROUND
Sepsis, a serious condition with high mortality, usually causes sepsis associated encephalopathy (SAE) that involves neuronal cell death. However, the cell death programs involved and their underlying mechanisms are not clear. This study aimed to explore the regulatory mechanisms of different cell death programs in SAE.
METHODS
A neonatal rat model of SAE was established by cecal ligation and perforation. Survival rate and vital signs (mean arterial pressure and heart rate) were monitored, nerve reflexes were evaluated, and cortical pathological changes were observed by hematoxylin and eosin staining. The expression of pyroptosis, apoptosis, and necroptosis (PANoptosis)-related proteins, mitogen- activated protein kinase (MAPK), and its upstream regulator toll-like receptor 9 (TLR9) were detected. The expression of TLR9 in neurons was observed by immunofluorescence staining. The ultrastructure of neurons was observed by transmission electron microscope.
RESULTS
First, PANoptosis was found in cortical nerve cells of the SAE rats. Meanwhile, the subunits of MAPKs, p38 MAPK, Jun N- terminal kinase, and extracellular signal-regulated kinase (ERK) were activated. After pharmacologically inhibiting each of the subunits, only p38 MAPK was found to be associated with PANoptosis. Furthermore, blocking the p38 MAPK signaling pathway activated necroptosis but inhibited apoptosis and pyroptosis. When necroptosis was pharmacologically inhibited, apoptosis and pyroptosis were reactivated. Finally, we found that the expression of TLR9, a regulator of MAPKs, was significantly increased in this model. After down-regulation of TLR9, p38 MAPK, and ERK signaling pathways were inhibited, which led to the inhibition of PANoptosis. Further analysis found that down-regulation of TLR9 improved the survival rate and reduced the pathological changes in SAE rats.
CONCLUSIONS
Our study showed that the programs comprising PANoptosis are activated simultaneously in SAE rats. TLR9 activated PANoptosis through the p38 MAPK signaling pathway. TLR9 may work as a potential target for SAE treatment.
Topics: Animals; Animals, Newborn; Apoptosis; Eosine Yellowish-(YS); Extracellular Signal-Regulated MAP Kinases; Hematoxylin; JNK Mitogen-Activated Protein Kinases; MAP Kinase Signaling System; Mitogens; Rats; Sepsis-Associated Encephalopathy; Signal Transduction; Toll-Like Receptor 9; p38 Mitogen-Activated Protein Kinases
PubMed: 35261352
DOI: 10.1097/CM9.0000000000002010