Posttranscriptional regulation of T helper cell fate decisions

Comprehensive pan-cancer analysis identifies the RNA-binding protein LRPPRC as a novel prognostic and immune biomarker

AIMS

RNA-binding proteins (RBPs) play pivotal roles in carcinogenesis and immunotherapy. Leucine-rich pentapeptide repeat-containing protein (LRPPRC) is crucial for RNA polyadenylation, transport, and stability. Although recent studies have suggested LRPPRC's potential role in tumor progression, its significance in tumor prognosis, diagnosis, and immunology remains unclear.

MAIN METHODS

We comprehensively analyzed LRPPRC expression in tumors using various databases, including Human Transcriptome Cell Atlas (HTCA), University of California Santa Cruz (UCSC), Human Protein Atlas (HPA), Sangerbox, TISIDB, GeneMANIA, GSCALite, and CellMiner. We examined the correlation between LRPPRC expression level and prognosis, immune infiltration, immunotherapy, methylation, biological function, and drug sensitivity. Single-cell analysis was performed using Tumor Immune Single Cell Hub (TISCH) and CancerSEA software. Patients with acute myeloid leukemia (AML) were categorized based on LRPPRC levels for functional and immune infiltration analyses. The role of LRPPRC in cancer was validated using in vitro experiments.

KEY FINDINGS

Our findings revealed that LRPPRC was highly expressed in almost all cancer types, indicating its significant prognostic and diagnostic potential. Notably, LRPPRC was associated with diverse immune features, such as immune cell infiltration, immune checkpoint genes, tumor mutational burden, and microsatellite instability, suggesting its value in guiding immunotherapy strategies. Within AML, the high-expression group had lower levels of immune cells, including CD8+ T cells. In vitro experiments confirmed the inhibitory effects of LRPPRC knockdown on AML cell proliferation.

SIGNIFICANCE

This study highlights LRPPRC as a reliable pan-cancer prognostic and immune biomarker, particularly in AML. It lays the groundwork for future research on LRPPRC-targeted cancer therapies.

The role of miRNAs in T helper cell development, activation, fate decisions and tumor immunity

T helper (Th) cells are central members of adaptive immunity and comprise the last line of defense against pathogen infection and malignant cell invasion by secreting specific cytokines. These cytokines then attract or induce the activation and differentiation of other immune cells, including antibody-producing B cells and cytotoxic CD8+ T cells. Therefore, the bidirectional communication between Th cells and tumor cells and their positioning within the tumor microenvironment (TME), especially the tumor immune microenvironment (TIME), sculpt the tumor immune landscape, which affects disease initiation and progression. The type, number, and condition of Th cells in the TME and TIME strongly affect tumor immunity, which is precisely regulated by key effectors, such as granzymes, perforins, cytokines, and chemokines. Moreover, microRNAs (miRNAs) have emerged as important regulators of Th cells. In this review, we discuss the role of miRNAs in regulating Th cell mediated adaptive immunity, focusing on the development, activation, fate decisions, and tumor immunity.

miRNA dosage control in development and human disease

In mammals, miRNAs recognize target mRNAs via base pairing, which leads to a complex 'multiple-to-multiple' regulatory network. Previous studies have focused on the regulatory mechanisms and functions of individual miRNAs, but alterations of many individual miRNAs do not strongly disturb the miRNA regulatory network. Recent studies revealed the important roles of global miRNA dosage control events in physiological processes and pathogenesis, suggesting that miRNAs can be considered as a 'cellular buffer' that controls cell fate. Here, we review the current state of research on how global miRNA dosage is tightly controlled to regulate development, tumorigenesis, neurophysiology, and immunity. We propose that methods of controlling global miRNA dosage may serve as effective therapeutic tools to cure human diseases.

Time-dependent regulation of cytokine production by RNA binding proteins defines T cell effector function

Potent T cell responses against infections and malignancies require a rapid yet tightly regulated production of toxic effector molecules. Their production level is defined by post-transcriptional events at 3' untranslated regions (3' UTRs). RNA binding proteins (RBPs) are key regulators in this process. With an RNA aptamer-based capture assay, we identify >130 RBPs interacting with IFNG, TNF, and IL2 3' UTRs in human T cells. RBP-RNA interactions show plasticity upon T cell activation. Furthermore, we uncover the intricate and time-dependent regulation of cytokine production by RBPs: whereas HuR supports early cytokine production, ZFP36L1, ATXN2L, and ZC3HAV1 dampen and shorten the production duration, each at different time points. Strikingly, even though ZFP36L1 deletion does not rescue the dysfunctional phenotype, tumor-infiltrating T cells produce more cytokines and cytotoxic molecules, resulting in superior anti-tumoral T cell responses. Our findings thus show that identifying RBP-RNA interactions reveals key modulators of T cell responses in health and disease.

Decoding systems immunological model of sphingolipids with IL-6/IL-17/IL-23 axes in L. major infection

IL-6, IL-17, IL-23 and IL-1β are the crucial cytokines controlling inflammatory and immune response during L. major infection. During cutaneous leishmaniasis, an important T helper cell type CD4⁺ Th17 subset plays a deterministic role in lesion formation through channelling infected macrophages and production of IL-1β, IL-6, IL-23 and IFN-γ. Ceramide derived sphingosine precursors may assist in pro-inflammatory cytokine response. However, the role of these metabolites in inflammation with pleiotropic pro-inflammatory cytokines in L. major infection is unknown. The present study indicates IL-6/IL-17/IL-23 and SPHK1-S1P-S1PRs signaling axes with the overexpression of SATB1 aiding in disease progression. Targeting SATB1 might modulate the secretion of pro-inflammatory cytokines and abnormal immune functioning, thereby killing the intracellular parasite. Systems immunological methods assisted in a step towards identifying the key to the mystery of crucial components and serving as an approach for therapeutic intervention in L. major infection.

Beneficial effects of naringenin and morin on interleukin-5 and reactive oxygen species production in BALB/c mice with ovalbumin-induced asthma

We investigated the effects of naringenin and morin on IL-5 and ROS production in PMA+ionomycin-treated EL-4 cells with the corroboration of their antioxidant and anti-inflammatory properties using an asthma-induced mouse model. The EL-4 cell line was used to study the outcomes of naringenin or morin, followed by cell viability studies. Western blot analysis and ELISA test were used to determine Th2 mediated cytokines. In vivo studies were carried out on BALB/c mice to induce allergic asthma using ovalbumin administered intraperitoneally. Intracellular ROS was determined using 2’,7’-dichlorodihydrofluorescein diacetate, followed by serum enzymatic (AST and ALT) estimations and inflammatory cell count in the bronchoalveolar lavage fluid (BALF) and lung tissues. Histopathological studies were conducted to examine lung tissue-stained architecture. Our findings suggested that naringenin and morin significantly suppressed IL-5 and ROS production via various pathways. Interestingly, by reducing NFAT activity, naringenin and morin stimulated HO-1 expression, thereby suppressing IL-5 secretion due to regulating the transcription factor Nrf2 via P13/Akt or ERK/JNK signalling pathways in EL-4 cells, demonstrating the involvement of HO-1 expression in inhibiting asthmatic inflammation. The increased inflammatory cells in the BALF were substantially decreased by both naringenin and morin, followed by inhibition in the elevated Th-2 cytokines levels. The TNF-α protein levels in an allergic asthma mouse model were significantly reduced by suppressing Akt phosphorylation and eosinophil formation. Recent findings confirmed that naringenin and morin possess the potential to control asthma-related immune responses through antioxidant and anti-inflammatory properties, indicating potential therapeutic agents or functional foods.

Diminished Peripheral CD29hi Cytotoxic CD4+ T Cells Are Associated With Deleterious Effects During SIV Infection

Cytotoxic CD4+ T cells (CD4+ CTLs) limit HIV pathogenesis, as evidenced in elite controllers (a subset of individuals who suppress the virus without the need for therapy). CD4+ CTLs have also been shown to kill HIV-infected macrophages. However, little is known about their contribution towards HIV persistence, how they are affected following exposure to immune modulators like morphine, and what factors maintain their frequencies and function. Further, the lack of robust markers to identify CD4+ CTLs in various animal models limits understanding of their role in HIV pathogenesis. We utilized various PBMC samples obtained from SIV infected and cART treated rhesus macaques exposed to morphine or saline and subjected to flow cytometry evaluations. Thereafter, we compared and correlated the expression of CD4+ CTL-specific markers to viral load and viral reservoir estimations in total CD4+ T cells. We found that CD29 could be reliably used as a marker to identify CD4+ CTLs in rhesus macaques since CD29hi CD4+ T cells secrete higher cytotoxic and proinflammatory cytokines following PMA/ionomycin or gag stimulation. In addition, this immune cell subset was depleted during untreated SIV infection. Strikingly, we also observed that early initiation of cART reconstitutes depleted CD29hi CD4+ T cells and restores their function. Furthermore, we noted that morphine exposure reduced the secretion of proinflammatory cytokines/cytotoxic molecules in CD29hi CD4+ T cells. Lastly, increased functionality of CD29hi CD4+ T cells as depicted by elevated levels of either IL-21 or granzyme B hi T Bet+ gag specific responses were linked to limiting the size of the replication-competent reservoir during cART treatment. Collectively, our data suggest that CD4+ CTLs are crucial in limiting SIV pathogenesis and persistence.

Defining the RBPome of primary T helper cells to elucidate higher-order Roquin-mediated mRNA regulation

Post-transcriptional gene regulation in T cells is dynamic and complex as targeted transcripts respond to various factors. This is evident for the Icos mRNA encoding an essential costimulatory receptor that is regulated by several RNA-binding proteins (RBP), including Roquin-1 and Roquin-2. Here, we identify a core RBPome of 798 mouse and 801 human T cell proteins by utilizing global RNA interactome capture (RNA-IC) and orthogonal organic phase separation (OOPS). The RBPome includes Stat1, Stat4 and Vav1 proteins suggesting unexpected functions for these transcription factors and signal transducers. Based on proximity to Roquin-1, we select ~50 RBPs for testing coregulation of Roquin-1/2 targets by induced expression in wild-type or Roquin-1/2-deficient T cells. Besides Roquin-independent contributions from Rbms1 and Cpeb4 we also show Roquin-1/2-dependent and target-specific coregulation of Icos by Celf1 and Igf2bp3. Connecting the cellular RBPome in a post-transcriptional context, we find contributions from multiple RBPs to the prototypic regulation of mRNA targets by individual trans-acting factors.

An extensive RNA binding protein atlas (RBPome) for primary T cells would be a useful resource. Here the authors use two different methods to characterise the mouse and human T cell RBPome and show regulation of Roquin-1/2 dependent and independent pathways.

T cells at work: How post-transcriptional mechanisms control T cell homeostasis and activation

T cells are central players of the adaptive immune system by protecting us from recurring infections and by killing malignant cells. Protective T cell responses rely on the concerted production of effector molecules such as cytolytic mediators, granzymes, and perforins, as well as pro-inflammatory cytokines and chemokines. Once activated, T cells drastically change their gene expression and rapidly respond to insults by producing ample amounts of effector molecules. In the absence of antigen, T cells remain in a quiescent state and survey our body for possible pathogenic insults. Resting T cells are, however, not inert, but continuously regulate their protein production to survive and to be prepared for possible re-infections. Here, we review our current knowledge on the regulation of gene expression in activated and quiescent T cells. We specifically focus on post-transcriptional mechanisms that define the protein output and that allow dormant cells to undergo active signaling and selective translation, keeping them poised for activation. Finally, we discuss which signals drive T cell survival and their preparedness to respond to insults and which mechanisms are involved in these processes.

Post-transcriptional control of T-cell cytokine production: Implications for cancer therapy

As part of the adaptive immune system, T cells are vital for the eradication of infected and malignantly transformed cells. To perform their protective function, T cells produce effector molecules that are either directly cytotoxic, such as granzymes, perforin, interferon-γ and tumour necrosis factor α, or attract and stimulate (immune) cells, such as interleukin-2. As these molecules can also induce immunopathology, tight control of their production is required. Indeed, inflammatory cytokine production is regulated on multiple levels. Firstly, locus accessibility and transcription factor availability and activity determine the amount of mRNA produced. Secondly, post-transcriptional mechanisms, influencing mRNA splicing/codon usage, stability, decay, localization and translation rate subsequently determine the amount of protein that is produced. In the immune suppressive environments of tumours, T cells gradually lose the capacity to produce effector molecules, resulting in tumour immune escape. Recently, the role of post-transcriptional regulation in fine-tuning T-cell effector function has become more appreciated. Furthermore, several groups have shown that exhausted or dysfunctional T cells from cancer patients or murine models possess mRNA for inflammatory mediators, but fail to produce effector molecules, hinting that post-transcriptional events also play a role in hampering tumour-infiltrating lymphocyte effector function. Here, the post-transcriptional regulatory events governing T-cell cytokine production are reviewed, with a specific focus on the importance of post-transcriptional regulation in anti-tumour responses. Furthermore, potential approaches to circumvent tumour-mediated dampening of T-cell effector function through the (dis)engagement of post-transcriptional events are explored, such as CRISPR/Cas9-mediated genome editing or chimeric antigen receptors.

TTP-mediated regulation of mRNA stability in immune cells contributes to adaptive immunity, immune tolerance and clinical applications

Dendritic cells (DCs) form a sentinel network to induce protective immunity against pathogens or self-tolerance. mRNA stability is an important part of the post-transcriptional regulation (PTR) that controls the maturation and function of DCs. In this review, we summarize the effects of TTP-mediated regulation of mRNA stability in DCs, focusing on DC maturation and antigen presentation, T cell activation and differentiation, immune tolerance and inflammation. We also discuss the potential DC-based immune treatment for HIV⁺ patients through regulation of mRNA stability. This review proposes the regulation of mRNA stability as a novel immune therapy for various inflammatory diseases, such as arthritis and dermatitis.

Cell-intrinsic mechanisms to restrain inflammatory responses in T lymphocytes

A mechanistic understanding of the regulatory circuits that control the effector responses of memory T helper lymphocytes, and in particular their ability to produce pro-inflammatory cytokines, may lead to effective therapeutic interventions in all immune-related diseases. Activation of T lymphocytes induces robust immune responses that in most cases lead to the complete eradication of invading pathogens or tumor cells. At the same time, however, such responses must be both highly controlled in magnitude and limited in time to avoid unnecessary damage. To achieve such sophisticated level of control, T lymphocytes have at their disposal an array of transcriptional and post-transcriptional regulatory mechanisms that ensure the acquisition of a phenotype that is tailored to the incoming stimulus while restraining unwarranted activation, eventually leading to the resolution of the inflammatory response. Here, we will discuss some of these cell-intrinsic mechanisms that control T cell responses and involve transcription factors, microRNAs, and RNA-binding proteins. We will also explore how the same mechanisms can be involved both in anti-tumor responses and in autoimmunity.

Toll-like receptor-2/7-mediated T cell activation: An innate potential to augment CD8+ T cell cytokine production

CD8⁺ T cells are critical to combat pathogens and eradicate malignantly transformed cells. To exert their effector function and kill target cells, T cells produce copious amounts of effector molecules, including the pro-inflammatory cytokines interferon γ, tumour necrosis factor α and interleukin 2. TCR triggering alone is sufficient to induce cytokine secretion by effector and memory CD8⁺ T cells. However, T cells can also be directly activated by pathogen-derived molecules, such as through the triggering of Toll-like receptors (TLRs). TLR-mediated pathogen sensing by T cells results in the production of only interferon γ. However, in particular when the antigen load on target cells is low, or when TCR affinity to the antigen is limited, antigen-experienced T cells can benefit from costimulatory signals. TLR stimulation can also function in a costimulatory fashion to enhance TCR triggering. Combined TCR and TLR triggering enhances the proliferation, memory formation and effector function of T cells, resulting in enhanced production of interferon γ, tumour necrosis factor α and interleukin 2. Therefore, TLR ligands or the exploitation of TLR signalling could provide novel opportunities for immunotherapy approaches. In fact, CD19 CAR T cells bearing an intracellular TLR2 costimulatory domain were recently employed to treat cancer patients in a clinical trial. Here, the current knowledge regarding TLR2/7 stimulation-induced cytokine production by T cells is reviewed. Specifically, the transcriptional and post-transcriptional pathways engaged upon TLR2/7 sensing and TLR2/7 signalling are discussed. Finally, the potential uses of TLRs to enhance the anti-tumor effector function of T cells are explored.

Citrus flavonoids suppress IL-5 and ROS through distinct pathways in PMA/ionomycin-induced EL-4 cells

Interleukin-5 (IL-5) strongly initiates the asthmatic inflammatory response, which affects 300 million patients with asthma annually worldwide, through oxidative stress generation. Citrus flavonoids have beneficial properties, such as anti-inflammatory and antioxidant properties, but the precise molecular mechanism of the inhibition of the asthmatic inflammatory response is still unclear. This study aimed to investigate the underlying mechanisms of ROS and IL-5 reduction with citrus flavonoid treatment in PMA/ionomycin-induced EL-4 cells. Our results showed that hesperetin and gardenin A dramatically suppressed ROS and IL-5 production through distinct pathways. Interestingly, hesperidin induced HO-1 expression through the transcription factor Nrf2 coupled with the PI3K/AKT or ERK/JNK signaling pathway, consequently downregulating NFAT activity and IL-5 secretion. Likewise, gardenin A induced HO-1 expression and subsequently suppressed IL-5 production by reducing NFAT activity and upregulating PPARγ in EL-4 cells, suggesting that inducing HO-1 expression may inhibit asthmatic inflammation. Altogether, hesperidin and gardenin A have great potential for regulating the asthma-associated immune responses through antioxidant properties.

Anti-tumor and immune modulating activity of T cell induced tumor-targeting effectors (TITE)

Adoptive transfer of Bispecific antibody Armed activated T cells (BATs) showed promising anti-tumor activity in clinical trials in solid tumors. The cytotoxic activity of BATs occurs upon engagement with tumor cells via the bispecific antibody (BiAb) bridge, which stimulates BATs to release cytotoxic molecules, cytokines, chemokines, and other signaling molecules extracellularly. We hypothesized that the release of BATs Induced Tumor-Targeting Effectors (TITE) by this complex interaction of T cells, bispecific antibody, and tumor cells may serve as a potent anti-tumor and immune-activating immunotherapeutic approach. In a 3D tumorsphere model, TITE showed potent cytotoxic activity against multiple breast cancer cell lines compared to control conditioned media (CM): Tumor-CM (T-CM), BATs-CM (B-CM), BiAb Armed PBMC-CM (BAP-CM) or PBMC-CM (P-CM). Multiplex cytokine analysis showed high levels of Th₁ cytokines and chemokines; phospho-protein signaling array data suggest that the prominent JAK1/STAT1 pathway may be responsible for the induction and release of Th₁ cytokines/chemokines in TITE. In xenograft breast cancer models, IV injections of 10× concentrated TITE (3×/week for 3 weeks; 150 μl TITE/injection) was able to inhibit tumor growth significantly (ICR/scid, p < 0.003; NSG p < 0.008) compared to the control mice. We tested the key components of the TITE for immune activating and anti-tumor activity individually and in combinations, the combination of IFN-γ, TNF-α and MIP-1β recapitulates the key activities of the TITE. In summary, master mix of active components of BATs-Tumor complex-derived TITE can provide a clinically controllable cell-free platform to target various tumor types regardless of the heterogeneous nature of the tumor cells and mutational tumor.

Gm15575 functions as a ceRNA to up-regulate CCL7 expression through sponging miR-686 in Th17 cells

Compelling evidence has demonstrated that Th17 cells play an essential role in the pathogenesis of multiple sclerosis (MS). Long noncoding RNAs (lncRNAs) have been confirmed as vital regulators of immune cell differentiation and other functions. However, whether and how lncRNAs influence Th17 cell differentiation and functional behaviors remain largely unclear. Here, we identified that a lncRNA, namely Gm15575, is specifically enriched in Th17 cells and spleen tissues of EAE mice. Functionally, knockdown of Gm15575 in Th17 cells suppressed the secretion of IL17A. Mechanistically, Gm15575 served as a competing endogenous RNA (ceRNA) to block the function of miR-686, positively regulating the expression of CCL7, a pro-inflammatory chemokine with high expression in Th17 cells, and Th17 differentiation. Taken together, our study revealed that Gm15575-miR-686 axis promoted the progression of EAE by regulating Th17 differentiation and expression of CCL7 which elucidated the pathogenesis of autoimmune diseases at genetic level. Gm15575 can be involved in the course of Th17-related autoimmune diseases.

Met-Flow, a strategy for single-cell metabolic analysis highlights dynamic changes in immune subpopulations

A complex interaction of anabolic and catabolic metabolism underpins the ability of leukocytes to mount an immune response. Their capacity to respond to changing environments by metabolic reprogramming is crucial to effector function. However, current methods lack the ability to interrogate this network of metabolic pathways at single-cell level within a heterogeneous population. We present Met-Flow, a flow cytometry-based method capturing the metabolic state of immune cells by targeting key proteins and rate-limiting enzymes across multiple pathways. We demonstrate the ability to simultaneously measure divergent metabolic profiles and dynamic remodeling in human peripheral blood mononuclear cells. Using Met-Flow, we discovered that glucose restriction and metabolic remodeling drive the expansion of an inflammatory central memory T cell subset. This method captures the complex metabolic state of any cell as it relates to phenotype and function, leading to a greater understanding of the role of metabolic heterogeneity in immune responses.

Patricia Ahl et al. present Met-Flow, a flow cytometry-based approach for capturing the metabolic state of immune cells across multiple pathways. The authors apply Met-Flow to a central memory T cell subset, showing the importance of glucose restriction and metabolic reprogramming to T cell polarization and expansion.

Human T cells employ conserved AU-rich elements to fine-tune IFN-γ production

Long‐lasting CD8⁺ T cell responses are critical in combatting infections and tumors. The pro‐inflammatory cytokine IFN‐γ is a key effector molecule herein. We recently showed that in murine T cells the production of IFN‐γ is tightly regulated through adenylate uridylate–rich elements (AREs) that are located in the 3′ untranslated region (UTR) of the Ifng mRNA molecule. Loss of AREs resulted in prolonged cytokine production in activated T cells and boosted anti‐tumoral T cell responses. Here, we investigated whether these findings can be translated to primary human T cells. Utilizing CRISPR‐Cas9 technology, we deleted the ARE region from the IFNG 3′ UTR in peripheral blood‐derived human T cells. Loss of AREs stabilized the IFNG mRNA in T cells and supported a higher proportion of IFN‐γ protein‐producing T cells. Importantly, combining MART‐1 T cell receptor engineering with ARE‐Del gene editing showed that this was also true for antigen‐specific activation of T cells. MART‐1‐specific ARE‐Del T cells showed higher percentages of IFN‐γ producing T cells in response to MART‐1 expressing tumor cells. Combined, our study reveals that ARE‐mediated posttranscriptional regulation is conserved between murine and human T cells. Furthermore, generating antigen‐specific ARE‐Del T cells is feasible, a feature that could potentially be used for therapeutical purposes.

Anti-psoriasis effect of water-processed rosin in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Rosin, an exudate of conifer trees such as Pinus masscnlana (Pinaceae), has been used to treat psoriasis for nearly two thousand years in China despite its so far undefined pharmacology. Unfortunately, the rosin intoxication is noted from time to time, but the water-boiled rosin (WBR) has been documented to be safer. This study was performed to evaluate the in vivo anti-psoriasis efficacy of WBR.

MATERIALS AND METHODS

The main phytochemicals in WBR were quantified by high performance liquid chromatography (HPLC). WBR was evaluated in the imiquimod-induced psoriasis-like inflammation mouse model for its anti-psoriasis effect at 130, 260, and 390 mg/kg, which were set according to the dose used for patients. Through a combination of q-PCR, flow cytometry, and histopathological and immunohistochemical (IHC) analysis, the in vivo efficacy was assessed in terms of the psoriasis area severity index (PASI), epidermal keratinocyte proliferation, Th1 and Th17 cell numbers in spleen, and mRNA expressions of inflammatory cytokines.

RESULT

Oral administration of WBR ameliorates the psoriasis-like dermatitis in the imiquimod-generated mouse model. In particular, WBR given at 260 or 390 mg/kg significantly restores the normal keratinization of dorsal lesion if compared with the untreated psoriatic mice. Such an effect was addressed to correlate to the Th1/Th17 cell reduction in spleen and the suppressed expression of IL-17A, IL-17F, IL-22, IL-23, TNF-α, K17, and proliferating cell nuclear antigen (PCNA) after the WBR administration.

CONCLUSION

WBR is effective in the imiquimod-induced psoriasis-like inflammation mouse model with the efficacy arising from its proliferation inhibition of Th1/Th17 cells and epidermal keratinocytes via the down-regulation of the relevant inflammatory cytokines such as IL-23, IL-17A, and IL-17F. Collectively, WBR harvested and processed in the traditional manner is an efficacious psoriasis-treating agent.

Post-transcriptional control of immune responses and its potential application

Inflammation is the host response against stresses such as infection. Although the inflammation process is required for the elimination of pathogens, uncontrolled inflammation leads to tissue destruction and inflammatory diseases. To avoid this, the inflammatory response is tightly controlled by multiple layers of regulation. Post-transcriptional control of inflammatory mRNAs is increasingly understood to perform critical roles in this process. This is mediated primarily by a set of RNA binding proteins (RBPs) including tristetraprolin, Roquin and Regnase-1, and RNA methylases. These key regulators coordinate the inflammatory response by modulating mRNA pools in both immune and local nonimmune cells. In this review, we provide an overview of the post-transcriptional coordination of immune responses in various tissues and discuss how RBP-mediated regulation of inflammation may be harnessed as a potential class of treatments for inflammatory diseases.

NF-κB Signaling and IL-4 Signaling Regulate SATB1 Expression via Alternative Promoter Usage During Th2 Differentiation

SATB1 is a genome organizer protein that is expressed in a lineage specific manner in CD4⁺ T-cells. SATB1 plays a crucial role in expression of multiple genes throughout the thymic development and peripheral differentiation of T cells. Although SATB1 function has been subjected to intense investigation, regulation of SATB1 gene expression remains poorly understood. Analysis of RNA-seq data revealed multiple transcription start sites at the upstream regulatory region of SATB1. We further demonstrated that SATB1 gene is expressed via alternative promoters during T-helper (Th) cell differentiation. The proximal promoter “P1” is used more by the naïve and activated CD4⁺ T-cells whereas the middle “P2” and the distal “P3” promoters are used at a significantly higher level by polarized T-helper cells. Cytokine and TCR signaling play crucial roles toward SATB1 alternative promoter usage. Under Th2 polarization conditions, transcription factor STAT6, which operates downstream of the cytokine signaling binds to the P2 and P3 promoters. Genetic perturbation by knockout and chemical inhibition of STAT6 activation resulted in the loss of P2 and P3 promoter activity. Moreover, chemical inhibition of activation of NF-κB, a transcription factor that operates downstream of the TCR signaling, also resulted in reduced P2 and P3 promoter usage. Furthermore, usage of the P1 promoter correlated with lower SATB1 protein expression whereas P2 and P3 promoter usage correlated with higher SATB1 protein expression. Thus, the promoter switch might play a crucial role in fine-tuning of SATB1 protein expression in a cell type specific manner.

Diabetic gut microbiota dysbiosis as an inflammaging and immunosenescence condition that fosters progression of retinopathy and nephropathy

The increased prevalence of type 2 diabetes mellitus (T2DM) and life expectancy of diabetic patients fosters the worldwide prevalence of retinopathy and nephropathy, two major microvascular complications that have been difficult to treat with contemporary glucose-lowering medications. The gut microbiota (GM) has become a lively field research in the last years; there is a growing recognition that altered intestinal microbiota composition and function can directly impact the phenomenon of ageing and age-related disorders. In fact, human GM, envisaged as a potential source of novel therapeutics, strongly modulates host immunity and metabolism. It is now clear that gut dysbiosis and their products (e.g. p-cresyl sulfate, trimethylamine‑N‑oxide) dictate a secretory associated senescence phenotype and chronic low-grade inflammation, features shared in the physiological process of ageing ("inflammaging") as well as in T2DM ("metaflammation") and in its microvascular complications. This review provides an in-depth look on the crosstalk between GM, host immunity and metabolism. Further, it characterizes human GM signatures of elderly and T2DM patients. Finally, a comprehensive scrutiny of recent molecular findings (e.g. epigenetic changes) underlying causal relationships between GM dysbiosis and diabetic retinopathy/nephropathy complications is pinpointed, with the ultimate goal to unravel potential pathophysiological mechanisms that may be explored, in a near future, as personalized disease-modifying therapeutic approaches.

MicroRNAs as modulators of T cell functions in cancer

MicroRNAs (miRNAs) are short RNA molecules that regulate gene expression post-transcriptionally. They have emerged as important modulators of T lymphocyte biology, influencing cell activation, differentiation and proliferation in response to environmental signals. Here, we will discuss how miRNAs expressed by T cells can influence two key aspects of tumorigenesis, namely the direct, cell-intrinsic oncogenic transformation of T lymphocytes, as well as the indirect effects on tumor growth mediated by altered immune surveillance. We will specifically focus on three miRNAs that have been shown to regulate different aspects of T cell biology in both physiological and pathological conditions, namely miR-155, miR-146a and miR-181a. We aim at providing examples of the fundamental importance of miRNA-regulated networks in determining the fate of T lymphocytes during oncogenic transformation and in the control of tumor growth.