The role of CaMK4 in immune responses

Abnormal energy metabolism in the pathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a severe autoimmune disease with significant socioeconomic impact worldwide. Orderly energy metabolism is essential for normal immune function, and disordered energy metabolism is increasingly recognized as an important contributor to the pathogenesis of SLE. Disorders of energy metabolism are characterized by increased reactive oxygen species, ATP deficiency, and abnormal metabolic pathways. Oxygen and mitochondria are critical for the production of ATP, and both mitochondrial dysfunction and hypoxia affect the energy production processes. In addition, several signaling pathways, including mammalian target of rapamycin (mTOR)/adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) signaling and the hypoxia-inducible factor (HIF) pathway also play important regulatory roles in energy metabolism. Furthermore, drugs with clear clinical effects on SLE, such as sirolimus, metformin, and tacrolimus, have been proven to improve the disordered energy metabolism of immune cells, suggesting the potential of targeting energy metabolism for the treatment of SLE. Moreover, several metabolic modulators under investigation are expected to have potential therapeutic effects in SLE. This review aimed to gain insights into the role and mechanism of abnormal energy metabolism in the pathogenesis of SLE, and summarizes the progression of metabolic modulator in the treatment of SLE.

CaMK4: Structure, physiological functions, and therapeutic potential

Calcium/calmodulin-dependent protein kinase IV (CaMK4) is a versatile serine/threonine kinase involved in various cellular functions. It regulates T-cell differentiation, podocyte function, tumor cell proliferation/apoptosis, β cell mass, and insulin sensitivity. However, the underlying molecular mechanisms are complex and remain incompletely understood. The aims of this review are to highlight the latest advances in the regulatory mechanisms of CaMK4 underlying T-cell imbalance and parenchymal cell mass in multiple diseases. The structural motifs and activation of CaMK4, as well as the potential role of CaMK4 as a novel therapeutic target are also discussed.

Understanding the pathogenic significance of altered calcium-calmodulin signaling in T cells in autoimmune diseases

Calcium/calmodulin-dependent protein kinase IV (CaMK4) serves as a pivotal mediator in the regulation of gene expression, influencing the activity of transcription factors within a variety of immune cells, including T cells. Altered CaMK4 signaling is implicated in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, and psoriasis, which are characterized by dysregulated immune responses and clinical complexity. These conditions share common disturbances in immune cell functionality, cytokine production, and autoantibody generation, all of which are associated with disrupted calcium-calmodulin signaling. This review underscores the consequences of dysregulated CaMK4 signaling across these diseases, with an emphasis on its impact on Th17 differentiation and T cell metabolism-processes central to maintaining immune homeostasis. A comprehensive understanding of roles of CaMK4 in gene regulation across various autoimmune disorders holds promise for the development of targeted therapies, particularly for diseases driven by Th17 cell dysregulation.

Tissue-resident memory T cell signatures from single-cell analysis associated with better melanoma prognosis

Tissue-resident memory T cells (TRM) are a specialized T cell population residing in peripheral tissues. The presence and potential impact of TRM in the tumor immune microenvironment (TIME) remain to be elucidated. Here, we systematically investigated the relationship between TRM and melanoma TIME based on multiple clinical single-cell RNA-seq datasets and developed signatures indicative of TRM infiltration. TRM infiltration is associated with longer overall survival and abundance of T cells, NK cells, M1 macrophages, and memory B cells in the TIME. A 22-gene TRM-derived risk score was further developed to effectively classify patients into low- and high-risk categories, distinguishing overall survival and immune activation, particularly in T cell-mediated responses. Altogether, our analysis suggests that TRM abundance is associated with melanoma TIME activation and patient survival, and the TRM-based machine learning model can potentially predict prognosis in melanoma patients.

Urinary biomarkers associated with podocyte injury in lupus nephritis

The most prevalent and devastating form of organ damage in systemic lupus erythematosus (SLE) is lupus nephritis (LN). LN is characterized by glomerular injury, inflammation, cell proliferation, and necrosis, leading to podocyte injury and tubular epithelial cell damage. Assays for urine biomarkers have demonstrated significant promise in the early detection of LN, evaluation of disease activity, and tracking of reaction to therapy. This is because they are non-invasive, allow for frequent monitoring and easy self-collection, transport and storage. Podocyte injury is believed to be a essential factor in LN. The extent and type of podocyte injury could be connected to the severity of proteinuria, making podocyte-derived cellular debris and injury-related urinary proteins potential markers for the diagnosis and monitoring of LN. This article focuses on studies examining urinary biomarkers associated with podocyte injury in LN, offering fresh perspectives on the application of biomarkers in the early detection and management of LN.

The relationship between CD4+ T cell glycolysis and their functions

CD4⁺ T cells are effector T cells (Teffs) produced by the differentiation of initial T cells in peripheral lymphoid tissue after being attacked by antigens, and have an indispensable role in the development and activation of B cells and CD8⁺ T cells to regulate and assist immunity. In this review, we provide a new perspective on the relationship between CD4⁺ T cell glycolysis and its function. We summarize the effects of changes in the glycolysis level of CD4⁺ T cells on their activation, differentiation, proliferation, and survival. In addition, we emphasize that regulation of the glycolysis level of CD4⁺ T cells changes their inflammatory phenotypes and function. The study of immune metabolism has received more attention recently, but more work is needed to answer many open questions.

Inhibition of calcium/calmodulin-dependent protein kinase IV in arthritis: dual effect on Th17 cell activation and osteoclastogenesis

OBJECTIVE

To investigate the role of calcium/calmodulin-dependent protein kinase IV (CaMK4) in the development of joint injury in a mouse model of arthritis and patients with RA.

METHODS

Camk4-deficient, Camk4flox/floxLck-Cre, and mice treated with CaMK4 inhibitor KN-93 or KN-93 encapsulated in nanoparticles tagged with CD4 or CD8 antibodies were subjected to collagen-induced arthritis (CIA). Inflammatory cytokine levels, humoral immune response, synovitis, and T-cell activation were recorded. CAMK4 gene expression was measured in CD4+ T cells from healthy participants and patients with active RA. Micro-CT and histology were used to assess joint pathology. CD4+ and CD14+ cells in patients with RA were subjected to Th17 or osteoclast differentiation, respectively.

RESULTS

CaMK4-deficient mice subjected to CIA displayed improved clinical scores and decreased numbers of Th17 cells. KN-93 treatment significantly reduced joint destruction by decreasing the production of inflammatory cytokines. Furthermore, Camk4flox/floxLck-Cre mice and mice treated with KN93-loaded CD4 antibody-tagged nanoparticles developed fewer Th17 cells and less severe arthritis. CaMK4 inhibition mitigated IL-17 production by CD4+ cells in patients with RA. The number of in vitro differentiated osteoclasts from CD14+ cells in patients with RA was significantly decreased with CaMK4 inhibitors.

CONCLUSION

Using global and CD4-cell-targeted pharmacologic approaches and conditionally deficient mice, we demonstrate that CaMK4 is important in the development of arthritis. Using ex vivo cell cultures from patients with RA, CaMK4 is important for both Th17 generation and osteoclastogenesis. We propose that CaMK4 inhibition represents a new approach to control the development of arthritis.

Analysis of Circulating Immune Subsets in Primary Colorectal Cancer

The development and progression of colorectal cancer (CRC) are known to be affected by the interplay between tumor and immune cells. However, the impact of CRC cells on the systemic immunity has yet to be elucidated. We aimed to comprehensively evaluate the circulating immune subsets and transcriptional profiles of CRC patients. In contrast to healthy controls (HCs), CRC patients had a lower percentage of B and T lymphocytes, T helper (Th) cells, non-classical monocytes, dendritic cells, and a higher proportion of polymorphonuclear myeloid-derived suppressor cells, as well as a reduced expression of CD69 on NK cells. Therefore, CRC patients exhibit a more evident systemic immune suppression than HCs. A diagnostic model integrating seven immune subsets was constructed to distinguish CRC patients from HCs with an AUC of 1.000. Moreover, NR3C2, CAMK4, and TRAT1 were identified as candidate genes regulating the number of Th cells in CRC patients. The altered composition of circulating immune cells in CRC could complement the regional immune status of the tumor microenvironment and contribute to the discovery of immune-related biomarkers for the diagnosis of CRC.

An allergenic plant calmodulin from Artemisia pollen primes human DCs leads to Th2 polarization

Artemisia pollen is the major cause of seasonal allergic respiratory diseases in the northern hemisphere. About 28.57% of Artemisia allergic patients’ IgE can recognize ArtCaM, a novel allergenic calmodulin from Artemisia identified in this study. These patients exhibited stronger allergic reactions and a longer duration of allergic symptoms. However, the signaling mechanism that triggers these allergic reactions is not fully understood. In this study, we found that extracellular ArtCaM directly induces the maturation of human dendritic cells (DCs), which is attributed to a series of Ca²⁺ relevant cascades, including Ca²⁺/NFAT/CaMKs. ArtCaM alone induces inflammatory response toward Th1, Th17, and Treg. Interestingly, a combination of ArtCaM and anti-ArtCaM IgE led to Th2 polarization. The putative mechanism is that anti-ArtCaM IgE partially blocks the ArtCaM-induced ERK signal, but does not affect Ca²⁺-dependent cascades. The crosstalk between ERK and Ca²⁺ signal primes DCs maturation and Th2 polarization. In summary, ArtCaM related to clinical symptoms when combined with anti-ArtCaM IgE, could be a novel allergen to activate DCs and promote Th2 polarization. Such findings provide mechanistic insights into Th2 polarization in allergic sensitization and pave the way for novel preventive and therapeutic strategies for efficient management of such pollen allergic disease.

CFNAs of RBCs affect the release of inflammatory factors through the expression of CaMKIV in macrophages

BACKGROUND

Blood transfusions reportedly modulate the recipient's immune system. Transfusion-related immunomodulation has been suggested as a mechanism of some adverse clinical outcomes. Extracellular nucleic acids circulate in plasma and activate relevant immune responses, but little is known about their mechanism of action in transfusion-related immunomodulation (TRIM). The aim of this study was to investigate the effects of cell-free nucleic acids (CFNAs) produced by red blood cells (RBCs) on innate immunity, especially peripheral blood mononuclear cells (PBMCs) and macrophages, and to investigate the mechanism of action.

METHODS

Differentially expressed genes (DEGs) between PBMCs exposed to RBC-produced CFNA and normal PBMCs were analyzed by gene expression data combined with bioinformatics. KEGG and GO enrichment analyses were performed for the DEGs, and in vitro experiments were performed for the effects of key genes on the release of inflammatory factors from macrophages.

RESULTS

Analysis of microarray data showed that exposure of monocytes to RBC-produced CFNAs increased the expression of genes involved in the innate immune response, including chemokines, chemokine receptors, and innate response receptors, and that calcium channel activity was highly regulated, with a key gene being CaMKIV. CaMKIV played a critical role in LPS-induced inflammatory factor release from macrophages, which was exacerbated by overexpression of the CaMKIV gene.

CONCLUSION

RBCs regulate the release of inflammatory factors during blood transfusion by releasing CFNAs and affecting expression of the CaMKIV gene in PBMCs or macrophages, which is a potential regulatory mechanism of blood transfusion-related immune regulation and related adverse reactions.

CaMK4 Promotes Acute Lung Injury Through NLRP3 Inflammasome Activation in Type II Alveolar Epithelial Cell

Background

Type II alveolar epithelial cell (AEC II), in addition to its roles in maintaining lung homeostasis, takes an active role in inflammatory response during acute lung injury (ALI). Ca2+/calmodulin-dependent protein kinase IV (CaMK4) activated by Ca2+/calmodulin signaling, has been implicated in immune responses. This study was to investigate the roles of CaMK4 in the development of ALI and the underlying mechanisms.

Methods

CaMK4 inhibitor KN-93 was used to investigate the effects of CaMK4 on NLRP3 inflammasome activation. The effects of KN-93 on disease development of lipopolysaccharide (LPS)-induced ALI were also evaluated. The role of CaMK4 on NLRP3 inflammasome activation was explored in human AEC II cell line A549 using KN-93 or CaMK4 siRNA. NLRP3 inflammasome activation was measured by histology immunofluorescence and Western blot. IL-1β and IL-18 were measured by ELISA.

Results

Phosphorylation of CaMK4 and the expression of NLRP3 and Caspase-1 p20 were increased in the lungs of LPS-induced ALI mice, which was suppressed by KN-93 as measured by Western blot. Further, the activation of NLRP3 inflammasome was detected in AEC II from patients with acute respiratory distress syndrome (ARDS) and LPS-induced ALI mice. In vitro, inhibition or silencing CaMK4 in AEC II significantly inhibited NLRP3 inflammasome activation, resulting in reduced IL-1β production. The inhibition of NLRP3 inflammasome and decreased IL-1β/IL-18 production by KN-93 led to reduced inflammatory infiltration and ameliorated lung injury in LPS-induced ALI mice.

Conclusion

CaMK4 controls the activation of NLRP3 inflammasome in AEC II during LPS-induced ALI. CaMK4 inhibition could be a novel therapeutic approach for the treatment of ALI.

A CD8+ T Cell-Related Genes Expression Signature Predicts Prognosis and the Efficacy of Immunotherapy in Breast Cancer

Immunotherapy has been applied to patients with breast cancer. However, only part of patients benefits from the current immunotherapy. Accurate prediction of individual response to immunotherapy can be beneficial for breast cancer management. CD8+ T cells are the main force of anti-tumor immunity. This study aimed to establish a CD8+ T cell-related gene expression signature for prediction of breast cancer prognostic and immunotherapy efficacy. RNA-seq transcriptomic data was the basics of this research. Weighted gene co-expression network analysis (WGCNA) and the least absolute shrinkage and selection operator (LASSO) Cox regression analysis established the prognostic signature. We identified 290 CD8+ T cell-related genes in the training set and established a risk-score model based on 8-genes panel (SOCS1, IL10, CAMK4, CXCL13, KIR2DS4, TESPA1, CD70 and ICAM4). Subsequently, univariate Cox regression analysis suggested that high risk-score was a risk factor for breast cancer (HR = 3.1, 95%CI 2.0-4.8, P < 0.001). In tumor microenvironment, high-risk tumors present decreased tumor infiltrating CD8+ T cells and increased M2 macrophages. The low-risk patients may benefit more from immune checkpoint blockade immunotherapy than the high-risk patients. Moreover, breast tumors which sensitive to immune checkpoint inhibitor (ICI) showed higher IL10 expression.

Identifying changes in immune cells and constructing prognostic models using immune-related genes in post-burn immunosuppression

BACKGROUND

Burn patients are prone to infection as well as immunosuppression, which is a significant cause of death. Currently, there is a lack of prognostic biomarkers for immunosuppression in burn patients. This study was conducted to identify immune-related genes that are prognosis biomarkers in post-burn immunosuppression and potential targets for immunotherapy.

METHODS

We downloaded the gene expression profiles and clinical data of 213 burn patients and 79 healthy samples from the Gene Expression Omnibus (GEO) database. Immune infiltration analysis was used to identify the proportion of circulating immune cells. Functional enrichment analyses were carried out to identify immune-related genes that were used to build miRNA-mRNA networks to screen key genes. Next, we carried out correlation analysis between immune cells and key genes that were then used to construct logistic regression models in GSE77791 and were validated in GSE19743. Finally, we determined the expression of key genes in burn patients using quantitative reverse transcription polymerase chain reaction (qRT-PCR).

RESULTS

A total of 745 differently expressed genes were screened out: 299 were up-regulated and 446 were down-regulated. The number of Th-cells (CD4+) decreased while neutrophils increased in burn patients. The enrichment analysis showed that down-regulated genes were enriched in the T-cell activation pathway, while up-regulated genes were enriched in neutrophil activation response in burn patients. We screened out key genes (NFATC2, RORA, and CAMK4) that could be regulated by miRNA. The expression of key genes was related to the proportion of Th-cells (CD4+) and survival, and was an excellent predictor of prognosis in burns with an area under the curve (AUC) value of 0.945. Finally, we determined that NFATC2, RORA, and CAMK4 were down-regulated in burn patients.

CONCLUSION

We found that NFATC2, RORA, and CAMK4 were likely prognostic biomarkers in post-burn immunosuppression and potential immunotherapeutic targets to convert Th-cell dysfunction.

Increased cellular detoxification, cytoskeletal activities and protein transport explain physiological stress in a lagoon sponge

Tropical lagoon-inhabiting organisms live in highly irradiated ecosystems and are particularly susceptible to thermal stress resulting from climate change. However, despite living close to their thermal maxima, stress response mechanisms found in these organisms are poorly understood. We used a novel physiological-proteomic approach for sponges to describe the stress response mechanisms of the lagoon-inhabiting sponge Amphimedon navalis, when exposed to elevated seawater temperatures of +2°C and +4°C relative to a 26°C ambient temperature for 4 weeks. After 4 weeks of thermal exposure, the buoyant weight of the sponge experienced a significant decline, while its pumping rates and oxygen consumption rates significantly increased. Proteome dynamics revealed 50 differentially abundant proteins in sponges exposed to elevated temperature, suggesting that shifts in the sponge proteome were potential drivers of physiological dysfunction. Thermal stress promoted an increase in detoxification proteins, such as catalase, suggesting that an excess of reactive oxygen species in sponge cells was responsible for the significant increase in oxygen consumption. Elevated temperature also disrupted cellular growth and cell proliferation, promoting the loss of sponge biomass, and the high abundance of multiple α-tubulin chain proteins also indicated an increase in cytoskeletal activities within sponge cells, which may have induced the increase in sponge pumping rate. Our results show that sustained thermal exposure in susceptible lagoonal sponges may induce significant disruption of cellular homeostasis, leading to physiological dysfunction, and that a combined physiological-proteomic approach may provide new insights into physiological functions and cellular processes occurring in sponges.

Newly characterized bovine mammary stromal region with epithelial properties supports representative epithelial outgrowth development from transplanted stem cells

Limited outgrowth development of bovine mammary epithelial stem cells transplanted into de-epithelialized mouse fat pads restricts advanced studies on this productive organ's development and renewal. We challenged the mouse-bovine incompatibility by implanting parenchymal adjacent or distant bovine stromal layers (close and far stroma, respectively) into the mouse fat pad to serve as an endogenous niche for transplanted stem cells. The close stroma better supported stem cell take rate and outgrowth development. The diameter of these open duct-like structures represented and occasionally exceeded that of the endogenous ducts and appeared 8.3-fold wider than the capsule-like structures developed in the mouse fat pad after similar cell transplantation. RNA-Seq revealed lower complement activity in this layer, associated with secretion of specific laminins and WNT proteins favoring epithelial outgrowth development. The close stroma appeared genetically more similar to the parenchyma than to the far stroma due to epithelial characteristics, mainly of fibroblasts, including expression of epithelial markers, milk protein genes, and functional mammary claudins. Gene markers and activators of the mesenchymal-to-epithelial transition were highly enriched in the epithelial gene cluster and may contribute to the acquired epithelial properties of this stromal layer.

Transcriptional Profiling of Exosomes Derived from Staphylococcus aureus-Infected Bovine Mammary Epithelial Cell Line MAC-T by RNA-Seq Analysis

Mastitis is a common disease in the dairy industry that causes huge economic losses worldwide. Exosomes (carrying proteins, miRNA, lncRNA, etc.) play a vital role in the regulation of immune response. lncRNA can play a variety of regulatory roles by combining with protein, RNA, and DNA. The expression of mRNA and lncRNA in exosomes derived from bovine mammary epithelial cells infected by S. aureus is rarely understood. To explore this issue, RNA sequencing analysis was performed on exosomes derived from S. aureus-infected and noninfected MAC-T cells. Analysis of the sequencing results showed that there were 186 differentially expressed genes, 431 differentially expressed mRNAs and 19 differentially expressed lncRNAs in the exosomes derived from S. aureus-infected and noninfected MAC-T cells. By predicting lncRNA target genes, it was found that 19 differentially expressed lncRNAs all acted on multiple mRNAs in cis and trans. GO analysis revealed that differentially expressed genes and lncRNA target genes played significant roles in such metabolism (reactive oxygen species metabolic processes), transmembrane transport, cellular response to DNA damage stimulus, and response to cytokines. KEGG enrichment indicated that lncRNA target genes gathered in the TNF pathway, Notch pathway, MAPK pathway, NF-kappa B pathway, Hippo pathway, p53 pathway, reactive oxygen species metabolic processes, and longevity regulating pathway. In summary, all data indicated that differentially expressed gene, mRNA, and lncRNA in transcriptional profiling of exosomes participated in bacterial invasion and adhesion, oxidative stress, inflammation, and apoptosis-related signaling pathway. The data obtained in this study would provide valuable resource for understanding the lncRNA information in exosomes derived from dairy cow mammary epithelial cells and conduced to the study of S. aureus infection in dairy cow mammary glands.

Flexible Mixture Model Approaches That Accommodate Footprint Size Variability for Robust Detection of Balancing Selection

Long-term balancing selection typically leaves narrow footprints of increased genetic diversity, and therefore most detection approaches only achieve optimal performances when sufficiently small genomic regions (i.e., windows) are examined. Such methods are sensitive to window sizes and suffer substantial losses in power when windows are large. Here, we employ mixture models to construct a set of five composite likelihood ratio test statistics, which we collectively term B statistics. These statistics are agnostic to window sizes and can operate on diverse forms of input data. Through simulations, we show that they exhibit comparable power to the best-performing current methods, and retain substantially high power regardless of window sizes. They also display considerable robustness to high mutation rates and uneven recombination landscapes, as well as an array of other common confounding scenarios. Moreover, we applied a specific version of the B statistics, termed B2, to a human population-genomic data set and recovered many top candidates from prior studies, including the then-uncharacterized STPG2 and CCDC169-SOHLH2, both of which are related to gamete functions. We further applied B2 on a bonobo population-genomic data set. In addition to the MHC-DQ genes, we uncovered several novel candidate genes, such as KLRD1, involved in viral defense, and SCN9A, associated with pain perception. Finally, we show that our methods can be extended to account for multiallelic balancing selection and integrated the set of statistics into open-source software named BalLeRMix for future applications by the scientific community.

CaMK4-dependent phosphorylation of Akt/mTOR underlies Th17 excessive activation in experimental autoimmune prostatitis

Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) is a complicated syndrome characterized by genitourinary pain in the absence of bacterial infection. Th17 cell-driven autoimmunity has been proposed as a cause of CP/CPPS. However, the factors that promote Th17-driven autoimmunity in experimental autoimmune prostatitis (EAP) and the molecular mechanisms are still largely unknown. Here, we showed that Th17 cells were excessively activated, and blockade of IL-17A could effectively ameliorate various symptoms in EAP. Furthermore, we revealed that calcium/calmodulin-dependent kinase Ⅳ (CaMK4), especially Thr196 p-CaMK4 was increased in the Th17 cells of the EAP group, which were activated by intracellular cytosolic Ca2+ . Pharmacologic and genetic inhibition of CaMK4 decreased the proportion of Th17 cells, and the protein and mRNA level of IL-17A, IL-22, and RORγt. The phosphorylation of CaMK4 was dependent on the increase in intracellular cytosolic Ca2+ concentration in Th17 cells. A mechanistic study demonstrated that inhibition of CaMK4 reduced IL-17A production by decreasing the phosphorylation of Akt-mTOR, which was well accepted to positively regulate Th17 differentiation. Collectively, our results demonstrated that Ca2+ -CaMK4-Akt/mTOR-IL-17A axis inhibition may serve as a promising therapeutic strategy for CP/CPPS.

Calmodulin-dependent signalling pathways are activated and mediate the acute inflammatory response of injured skeletal muscle

KEY POINTS

There is a close relationship between skeletal muscle physiology and Ca²⁺ /calmodulin (CaM) signalling. Despite the effects of Ca²⁺ /CaM signalling on immune and inflammatory responses having been extensively explored, few studies have investigated the role of CaM pathway activation on the post-injury muscle inflammatory response. In this study, we investigated the role of CaM-dependent signalling in muscle inflammation in cardiotoxin induced myoinjuries in mice. The Ca²⁺ /calmodulin-dependent protein kinase II (CaMII), Ca²⁺ /calmodulin-dependent protein kinase IV (CaMKIV), and nuclear factor of activated T cells (NFAT) pathways are likely to be simultaneously activated in muscle cells and in infiltrating lymphocytes and to regulate the immune behaviours of myofibres in an inflammatory environment, and these pathways ultimately affect the outcome of muscle inflammation.

ABSTRACT

Calcium/calmodulin (Ca²⁺ /CaM) signalling is essential for immune and inflammatory responses in tissues. However, it is unclear if Ca²⁺ /CaM signalling interferes with muscle inflammation. Here we investigated the roles of CaM-dependent signalling in muscle inflammation in mice that had acute myoinjuries in the tibialis anterior muscle induced by intramuscular cardiotoxin (CTX) injections and received intraperitoneal injections of either the CaM inhibitor calmidazolium chloride (CCL) or CaM agonist calcium-like peptide 1 (CALP1). Multiple inflammatory parameters, including muscle autoantigens and toll-like receptors, mononuclear cell infiltration, cytokines and chemokines associated with peripheral muscle inflammation, were examined after the injury and treatment. CALP1 treatment enhanced intramuscular infiltration of monocytes/macrophages into the damaged tibialis anterior muscle and up-regulated mRNA and protein levels of muscle autoantigens (Mi-2, HARS and Ku70) and Toll-like receptor 3 (TLR3), and mRNA levels of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), Monocyte chemoattractant protein-1 (MCP1), Monocyte chemoattractant protein-3 (MCP3) and Macrophage inflammatory protein-1(MIP-1α) in damaged muscle. In contrast, CCL treatment decreased the intramuscular cell infiltration and mRNA levels of the inflammatory mediators. After CALP1 treatment, a substantial up-regulation in Ca²⁺ /calmodulin-dependent protein kinase II (CaMKII), Ca²⁺ /calmodulin-dependent protein kinase IV (CaMKIV) and nuclear factor of activated T cells (NFAT) activity was detected in CD45⁺ cells isolated from the damaged muscle. More pro-inflammatory F4/80⁺ Ly-6C⁺ cells were detected in CD45-gated cells after CALP1 treatment than in those after CCL treatment or no treatment. Consistently, in interferon-γ-stimulated cultured myoblasts and myotubes, CALP1 treatment up-regulated the activities of CaMKII, CaMKIV and NFAT, and levels of class I/II major histocompatibility complexes (MHC-I/II) and TLR3. Our findings demonstrated that CaM-dependent signalling pathways mediate the injury-induced acute muscle inflammatory response.

The role of IL-17 in systemic lupus erythematosus and its potential as a therapeutic target

INTRODUCTION

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibodies production and immune complex deposition with systemic clinical manifestations. Interleukin (IL)-17-producing cells play a crucial role in disease pathogenesis and represent an attractive therapeutic target. Areas covered: This review provides an update on the possibility of targeting IL-17 in SLE. The rational for this approach as well as currently available and future targets are discussed. Expert opinion: Although human expression studies and animal models indicate that IL-17 blocking may be a promising therapeutic strategy for SLE, direct evidence for IL-17 inhibition in SLE patients is unavailable. Biologic therapies and small-molecule drugs that target IL-17 production are required for the achievement of a favorable clinical effect in SLE patients.

High throughput screening, docking, and molecular dynamics studies to identify potential inhibitors of human calcium/calmodulin-dependent protein kinase IV

Calcium/calmodulin-dependent protein kinase IV (CAMKIV) is associated with many diseases including cancer and neurodegenerative disorders and thus being considered as a potential drug target. Here, we have employed the knowledge of three-dimensional structure of CAMKIV to identify new inhibitors for possible therapeutic intervention. We have employed virtual high throughput screening of 12,500 natural compounds of Zinc database to screen the best possible inhibitors of CAMKIV. Subsequently, 40 compounds which showed significant docking scores (-11.6 to -10.0 kcal/mol) were selected and further filtered through Lipinski rule and drug likeness parameter to get best inhibitors of CAMKIV. Docking results are indicating that ligands are binding to the hydrophobic cavity of the kinase domain of CAMKIV and forming a significant number of non-covalent interactions. Four compounds, ZINC02098378, ZINC12866674, ZINC04293413, and ZINC13403020, showing excellent binding affinity and drug likeness were subjected to molecular dynamics simulation to evaluate their mechanism of interaction and stability of protein-ligand complex. Our observations clearly suggesting that these selected ligands may be further employed for therapeutic intervention to address CAMKIV associated diseases. Communicated by Ramaswamy H. Sarma.