KCTD4 interacts with CLIC1 to disrupt calcium homeostasis and promote metastasis in esophageal cancer

Increasing evidences suggest the important role of calcium homeostasis in hallmarks of cancer, but its function and regulatory network in metastasis remain unclear. A comprehensive investigation of key regulators in cancer metastasis is urgently needed. Transcriptome sequencing (RNA-seq) of primary esophageal squamous cell carcinoma (ESCC) and matched metastatic tissues and a series of gain/loss-of-function experiments identified potassium channel tetramerization domain containing 4 (KCTD4) as a driver of cancer metastasis. KCTD4 expression was found upregulated in metastatic ESCC. High KCTD4 expression is associated with poor prognosis in patients with ESCC and contributes to cancer metastasis in vitro and in vivo. Mechanistically, KCTD4 binds to CLIC1 and disrupts its dimerization, thus increasing intracellular Ca2+ level to enhance NFATc1-dependent fibronectin transcription. KCTD4-induced fibronectin secretion activates fibroblasts in a paracrine manner, which in turn promotes cancer cell invasion via MMP24 signaling as positive feedback. Furthermore, a lead compound K279-0738 significantly suppresses cancer metastasis by targeting the KCTD4‒CLIC1 interaction, providing a potential therapeutic strategy. Taken together, our study not only uncovers KCTD4 as a regulator of calcium homeostasis, but also reveals KCTD4/CLIC1-Ca2+-NFATc1-fibronectin signaling as a novel mechanism of cancer metastasis. These findings validate KCTD4 as a potential prognostic biomarker and therapeutic target for ESCC.

The long non-coding RNA NRON promotes the development of cardiac hypertrophy in the murine heart

Physiological and pathological cardiovascular processes are tightly regulated by several cellular mechanisms. Non-coding RNAs, including long non-coding RNAs (lncRNAs), represent one important class of molecules involved in regulatory processes within the cell. The lncRNA non-coding repressor of NFAT (NRON) was described as a repressor of the nuclear factor of activated T cells (NFAT) in different in vitro studies. Although the calcineurin/NFAT-signaling pathway is one of the most important pathways in pathological cardiac hypertrophy, a potential regulation of hypertrophy by NRON in vivo has remained unclear. Applying subcellular fractionation and RNA fluorescence in situ hybridization (RNA-FISH), we found that, unlike what is known from T cells, in cardiomyocytes, NRON predominantly localizes to the nucleus. Hypertrophic stimulation in neonatal mouse cardiomyocytes led to a downregulation of NRON, while NRON overexpression led to an increase in expression of hypertrophic markers. To functionally investigate NRON in vivo, we used a mouse model of transverse aortic constriction (TAC)-induced hypertrophy and performed NRON gain- and loss-of-function experiments. Cardiomyocyte-specific NRON overexpression in vivo exacerbated TAC-induced hypertrophy, whereas cardiomyocyte-specific NRON deletion attenuated cardiac hypertrophy in mice. Heart weight, cardiomyocyte cell size, hypertrophic marker gene expression, and left ventricular mass showed a NRON-dependent regulation upon TAC-induced hypertrophy. In line with this, transcriptome profiling revealed an enrichment of anti-hypertrophic signaling pathways upon NRON-knockout during TAC-induced hypertrophy. This set of data refutes the hypothesized anti-hypertrophic role of NRON derived from in vitro studies in non-cardiac cells and suggests a novel regulatory function of NRON in the heart in vivo.

Immunosuppression Affects Neutrophil Functions: Does Calcineurin-NFAT Signaling Matter?

Neutrophils are innate immune cells with important roles in antimicrobial defense. However, impaired or dysregulated neutrophil function can result in host tissue damage, loss of homeostasis, hyperinflammation or pathological immunosuppression. A central link between neutrophil activation and immune outcomes is emerging to be the calcineurin-nuclear factor of activated T cells (NFAT) signaling pathway, which is activated by neutrophil detection of a microbial threat via pattern recognition receptors and results in inflammatory cytokine production. This potent pro-inflammatory pathway is also the target of several immunosuppressive drugs used for the treatment of autoimmune disorders, during solid organ and hematopoietic cell transplantations, and as a part of anti-cancer therapy: but what effects these drugs have on neutrophil function, and their broader consequences for immune homeostasis and microbial defense are not yet known. Here, we bring together the emerging literature describing pathology- and drug- induced neutrophil impairment, with particular focus on their effects on calcineurin-NFAT signaling in the innate immune compartment.

Pimecrolimus interferes the therapeutic efficacy of human mesenchymal stem cells in atopic dermatitis by regulating NFAT-COX2 signaling

Background

Human mesenchymal stem cells (hMSCs) therapy has recently been considered a promising treatment for atopic dermatitis (AD) due to their immunomodulation and tissue regeneration ability. In our previous studies, we demonstrated that hMSCs alleviate allergic inflammation in murine AD model by inhibiting the activation of mast cells and B cells. Also our phase I/IIa clinical trial showed clinical efficacy and safety of hMSCs in moderate-to-severe adult AD patients. However, hMSCs therapy against atopic dermatitis have had poor results in clinical field. Therefore, we investigated the reason behind this result. We hypothesized that drug–cell interaction could interfere with the therapeutic efficacy of stem cells, and investigated whether coadministration with pimecrolimus, one of the topical calcineurin inhibitors, could influence the therapeutic potential of human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) in AD.

Methods

hUCB-MSCs were subcutaneously injected to AD-induced mice with or without pimecrolimus topical application. To examine whether pimecrolimus influenced the immunomodulatory activity of hUCB-MSCs, hUCB-MSCs were treated with pimecrolimus.

Results

Pimecrolimus disturbed the therapeutic effect of hUCB-MSCs when they were co-administered in murine AD model. Moreover, the inhibitory functions of hUCB-MSCs against type 2 helper T (Th2) cell differentiation and mast cell activation were also deteriorated by pimecrolimus treatment. Interestingly, we found that pimecrolimus decreased the production of PGE₂, one of the most critical immunomodulatory factors in hUCB-MSCs. And we demonstrated that pimecrolimus downregulated COX2-PGE₂ axis by inhibiting nuclear translocation of NFAT3.

Conclusions

Coadministration of pimecrolimus with hMSCs could interfere with the therapeutic efficacy of hMSCs in atopic dermatitis, and this is the first study that figured out the interaction of hMSCs with other drugs in cell therapy of atopic dermatitis. Therefore, this study might give rise to improvement of the clinical application of hMSCs therapy and facilitate the widespread application of hMSCs in clinical field.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02547-8.

TRPC-mediated Ca2+ signaling and control of cellular functions

Canonical members of the TRP superfamily of ion channels have long been recognized as key elements of Ca²⁺ handling in a plethora of cell types. The emerging role of TRPC channels in human physiopathology has generated considerable interest in their pharmacological targeting, which requires detailed understanding of their molecular function. Although consent has been reached that receptor-phospholipase C (PLC) pathways and generation of lipid mediators constitute the prominent upstream signaling process that governs channel activity, multimodal sensing features of TRPC complexes have been demonstrated repeatedly. Downstream signaling by TRPC channels is similarly complex and involves the generation of local and global cellular Ca²⁺ rises, which are well-defined in space and time to govern specific cellular functions. These TRPC-mediated Ca²⁺ signals rely in part on Ca²⁺ permeation through the channels, but are essentially complemented by secondary mechanisms such as Ca²⁺ mobilization from storage sites and Na⁺/Ca²⁺ exchange, which involve coordinated interaction with signaling partners. Consequently, the control of cell functions by TRPC molecules is critically determined by dynamic assembly and subcellular targeting of the TRPC complexes. The very recent availability of high-resolution structure information on TRPC channel complexes has paved the way towards a comprehensive understanding of signal transduction by TRPC channels. Here, we summarize current concepts of cation permeation in TRPC complexes, TRPC-mediated shaping of cellular Ca²⁺ signals and the associated control of specific cell functions.

Non-coding RNAs in cardiac remodeling and heart failure

Heart failure is a leading cause of death in industrialized nations especially in an aging population. The recent improvements in cardiac revascularization therapy reduced death rates because of myocardial infarction but steadily increased the number of individuals developing cardiac remodeling and heart failure in the future. Conceptual novel approaches entering the clinics to treat cardiac remodeling and heart failure remain scarce. MicroRNAs emerged as powerful and dynamic modifiers of cardiovascular diseases. In this review, the current approaches using microRNAs as novel diagnostic and therapeutic strategies for cardiac remodeling and heart failure are highlighted. Other gene regulatory mechanisms presented include long (>200 bp) noncoding RNAs that function as an additional regulatory machinery of the genome controlling both transcriptional and post-transcriptional events also in the cardiovascular system.