Role of Hippo signaling in regulating immunity

Hippo kinases Mst1 and Mst2 maintain NK cell homeostasis by orchestrating metabolic state and transcriptional activity

Natural killer (NK) cells play a crucial role in immune response against viral infections and tumors. However, further investigation is needed to better understand the key molecules responsible for determining the fate and function of NK cells. In this study, we made an important discovery regarding the involvement of the Hippo kinases Mst1 and Mst2 as novel regulators in maintaining mouse NK cell homeostasis. The presence of high Mst1 and Mst2 (Mst1/2) activity in NK cells is essential for their proper development, survival and function in a canonical Hippo signaling independent mode. Mechanistically, Mst1/2 induce cellular quiescence by regulating the processes of proliferation and mitochondrial metabolism, thereby ensuring the development and survival of NK cells. Furthermore, Mst1/2 effectively sense IL-15 signaling and facilitate the activation of pSTAT3-TCF1, which contributes to NK cell homeostasis. Overall, our investigation highlights the crucial role of Mst1/2 as key regulators in metabolic reprogramming and transcriptional regulation for mouse NK cell survival and function, emphasizing the significance of cellular quiescence during NK cell development and functional maturation.

MST1/2 exerts a pivotal role in inducing neuroinflammation and Coxsackievirus-A10 replication by interacting with innate immunity

Coxsackievirus-A10 (CV-A10), responsible for the hand, foot and mouth disease (HFMD) pandemic, could cause serious central nervous system (CNS) complications. The underlying molecular basis of CV-A10 and host interactions inducing neuropathogenesis is still unclear. The Hippo signaling pathway, historically known for a dominator of organ development and homeostasis, has recently been implicated as an immune regulator. However, its role in host defense against CV-A10 has not been investigated. Herein, it was found that CV-A10 proliferated in HMC3 cells and promoted the release of inflammatory cytokines. Moreover, pattern recognition receptors (PRRs)-mediated pathways, including TLR3-TRIF-TRAF3-TBK1-NF-κB axis, RIG-I/MDA5-MAVS-TRAF3-TBK1-NF-κB axis and TLR7-MyD88-IRAK1/IRAK4-TRAF6-TAK1-NF-κB axis, were examined to be elevated under CV-A10 infection. Meanwhile, it was further uncovered that Hippo signaling pathway was inhibited in HMC3 cells with CV-A10 infection. Previous studies have been reported that there exist complex relations between innate immune and Hippo signaling pathway. Then, plasmids of knockdown and overexpression of MST1/2 were transfected into HMC3 cells. Our results showed that MST1/2 suppressed the levels of inflammatory cytokines via interacting with TBK1 and IRAK1, and also enhanced virus production via restricting IRF3 and IFN-β expressions. Overall, these data obviously pointed out that CV-A10 accelerated the formation of neuroinflammation by the effect of the Hippo pathway on the PRRs-mediated pathway, which delineates a negative immunoregulatory role for MST1/2 in CV-A10 infection and the potential for this pathway to be pharmacologically targeted to treat CV-A10.

Decoding the Impact of the Hippo Pathway on Different Cell Types in Heart Failure

The evolutionarily conserved Hippo pathway plays a pivotal role in governing a variety of biological processes. Heart failure (HF) is a major global health problem with a significant risk of mortality. This review provides a contemporary understanding of the Hippo pathway in regulating different cell types during HF. Through a systematic analysis of each component's regulatory mechanisms within the Hippo pathway, we elucidate their specific effects on cardiomyocytes, fibroblasts, endothelial cells, and macrophages in response to various cardiac injuries. Insights gleaned from both in vitro and in vivo studies highlight the therapeutic promise of targeting the Hippo pathway to address cardiovascular diseases, particularly HF.

Genetic mechanism of body size variation in groupers: Insights from phylotranscriptomics

Animal body size variation is of particular interest in evolutionary biology, but the genetic basis remains largely unknown. Previous studies have shown the presence of two parallel evolutionary genetic clusters within the fish genus Epinephelus with evident divergence in body size, providing an excellent opportunity to investigate the genetic basis of body size variation in vertebrates. Herein, we performed phylotranscriptomic analysis and reconstructed the phylogeny of 13 epinephelids originating from the South China Sea. Two genetic clades with an estimated divergence time of approximately 15.4 million years ago were correlated with large and small body size, respectively. A total of 180 rapidly evolving genes and two positively selected genes were identified between the two groups. Functional enrichment analyses of these candidate genes revealed distinct enrichment categories between the two groups. These pathways and genes may play important roles in body size variation in groupers through complex regulatory networks. Based on our results, we speculate that the ancestors of the two divergent groups of groupers may have adapted to different environments through habitat selection, leading to genetic variations in metabolic patterns, organ development, and lifespan, resulting in body size divergence between the two locally adapted populations. These findings provide important insights into the genetic mechanisms underlying body size variation in groupers and species differentiation.

Role of Hippo pathway dysregulation from gastrointestinal premalignant lesions to cancer

BACKGROUND

First identified in Drosophila melanogaster, the Hippo pathway is considered a major regulatory cascade controlling tissue homeostasis and organ development. Hippo signaling components include kinases whose activity regulates YAP and TAZ final effectors. In response to upstream stimuli, YAP and TAZ control transcriptional programs involved in cell proliferation, cytoskeletal reorganization and stemness.

MAIN TEXT

While fine tuning of Hippo cascade components is essential for maintaining the balance between proliferative and non-proliferative signals, pathway signaling is frequently dysregulated in gastrointestinal cancers. Also, YAP/TAZ aberrant activation has been described in conditions characterized by chronic inflammation that precede cancer development, suggesting a role of Hippo effectors in triggering carcinogenesis. In this review, we summarize the architecture of the Hippo pathway and discuss the involvement of signaling cascade unbalances in premalignant lesions of the gastrointestinal tract, providing a focus on the underlying molecular mechanisms.

CONCLUSIONS

The biology of premalignant Hippo signaling dysregulation needs further investigation in order to elucidate the evolutionary trajectories triggering cancer inititation and develop effective early therapeutic strategies targeting the Hippo/YAP pathway.

Discovery of a small-molecule NDR1 agonist for prostate cancer therapy

Prostatic cancer (PCa) is a common malignant neoplasm in men worldwide. Most patients develop castration-resistant prostate cancer (CRPC) after treatment with androgen deprivation therapy (ADT), usually resulting in death. Therefore, investigating new therapeutic targets and drugs for PCa patients is urgently needed. Nuclear Dbf2-related kinase 1 (NDR1), also known as STK38, is a serine/threonine kinase in the NDR/LATS kinase family that plays a critical role in cellular processes, including immunity, inflammation, metastasis, and tumorigenesis. It was reported that NDR1 inhibited the metastasis of prostate cancer cells by suppressing epithelial-mesenchymal transition (EMT), and decreased NDR1 expression might lead to a poorer prognosis, suggesting the enormous potential of NDR1 in antitumorigenesis. In this study, we characterized a small-molecule agonist named aNDR1, which specifically bound to NDR1 and potently promoted NDR1 expression, enzymatic activity and phosphorylation. aNDR1 exhibited drug-like properties, such as favorable stability, plasma protein binding capacity, cell membrane permeability, and PCa cell-specific inhibition, while having no obvious effect on normal prostate cells. Meanwhile, aNDR1 exhibited good antitumor activity both in vitro and in vivo. aNDR1 inhibited proliferation and migration of PCa cells and promoted apoptosis of PCa cells in vitro. We further found that aNDR1 inhibited subcutaneous tumors and lung metastatic nodules in vivo, with no obvious toxicity to the body. In summary, our study presents a potential small-molecule lead compound that targets NDR1 for clinical therapy of PCa patients.

Innate immune and proinflammatory signals activate the Hippo pathway via a Tak1-STRIPAK-Tao axis

The Hippo pathway controls developmental, homeostatic and regenerative tissue growth, and is frequently dysregulated in various diseases. Although this pathway can be activated by innate immune/inflammatory stimuli, the underlying mechanism is not fully understood. Here, we identify a conserved signaling cascade that leads to Hippo pathway activation by innate immune/inflammatory signals. We show that Tak1, a key kinase in innate immune/inflammatory signaling, activates the Hippo pathway by inducing the lysosomal degradation of Cka, an essential subunit of the STRIPAK PP2A complex that suppresses Hippo signaling. Suppression of STRIPAK results in the activation of Hippo pathway through Tao-Hpo signaling. We further show that Tak1-mediated Hippo signaling is involved in processes ranging from cell death to phagocytosis and innate immune memory. Our findings thus reveal a molecular connection between innate immune/inflammatory signaling and the evolutionally conserved Hippo pathway, thus contributing to our understanding of infectious, inflammatory and malignant diseases.

Molecules in the hippo pathway that regulate Th17 differentiation reveal the severity of ankylosing spondylitis

AIM

Ankylosing spondylitis (AS) is a chronic, progressive, and inflammatory autoimmune disease of unknown origin that affects the axial skeleton and sacroiliac joints, resulting in pain and loss of function. AS is characterized by the overdifferentiation of T helper 17 (Th17) cells, which contribute to the development of the disease. The Hippo signaling pathway is an important regulator of Th17 differentiation, but its role in patients with AS is unclear. We aimed to investigate the role of key molecules of the Hippo signaling pathway in inflammatory Th17 differentiation in patients with AS and to examine their correlation with disease stages.

METHODS

We examined the activity of the Hippo pathway in patients with AS and the regulation of Th17 differentiation during AS-mediated inflammation. Blood samples were collected from 60 patients with AS at various stages and 30 healthy controls. Peripheral blood mononuclear cells (PBMCs) were isolated from peripheral blood by density gradient centrifugation. The Serum Interleukin-17 (IL-17) levels in patients with AS and healthy controls were quantified by ELISA. The key molecules of Hippo pathway were assessed by real-time PCR for their mRNA expression, and protein levels were determined by Western blot analysis.

RESULTS

Elevated serum interleukin-17 (IL-17) levels were observed in patients with AS compared with healthy controls. The protein and mRNA levels of retinoic acid receptor-related orphan receptor γt (RORγt), transcriptional coactivator with a PDZ-binding motif (TAZ), and key upstream transcription factors in the Hippo signaling pathway were measured. The expression of RORγt and TAZ was increased in the blood of patients with AS, whereas the expression of other Hippo pathway proteins, such as MST1/2 and NDR1/2, was significantly decreased. Increased levels of IL-17 and TAZ were significantly associated with disease activity. In addition, MST1, MST2, and NDR1 levels were negatively correlated with TAZ, RORγt, and IL-17 levels.

CONCLUSION

Our findings suggest that the Hippo pathway plays a significant role in the regulation of Th17 differentiation and disease activity in patients with AS. The upregulation of TAZ and downregulation of key Hippo pathway proteins, such as MST1/2 and NDR1/2, may contribute to AS pathogenesis. These proteins may serve as biomarkers and may lead to the development of novel therapeutic strategies for AS.

MST1/2 in inflammation and immunity

The mammalian Sterile 20-like kinase 1/2 (MST1/2) belongs to the serine/threonine (GC) protein kinase superfamily. Collective studies confirm the vital role MST1/2 in inflammation and immunity. MST1/2 is closely related to the progress of inflammation. Generally, MST1/2 aggravates the inflammatory injury through MST1-JNK, MST1-mROS, MST1-Foxo3, and NF-κB pathways, as well as several regulatory factors such as tumor necrosis factor-α (TNF-α), mitochondrial extension factor 1 (MIEF1), and lipopolysaccharide (LPS). Moreover, MST1/2 is also involved in the regulation of immunity to balance immune activation and tolerance by regulating MST1/2-Rac, MST1-Akt1/c-myc, MST1-Foxos, MST1-STAT, Btk pathways, and lymphocyte function-related antigen 1 (LFA-1), which subsequently prevents immunodeficiency syndrome and autoimmune diseases. This article reviews the effects of MST1/2 on inflammation and immunity.

Bulk and single-nucleus RNA sequencing highlight immune pathways induced in individuals during an Ixodes scapularis tick bite

Ticks are hematophagous arthropods that use a complex mixture of salivary proteins to evade host defenses while taking a blood meal. Little is known about the immunological and physiological consequences of tick feeding on humans. Here, we performed the first bulk and single-nucleus RNA sequencing (snRNA-seq) of skin and blood of four persons presenting with naturally acquired, attached Ixodes scapularis ticks. Pathways and individual genes associated with innate and adaptive immunity were identified based on bulk RNA sequencing, including interleukin-17 signaling and platelet activation pathways at the site of tick attachment or in peripheral blood. snRNA-seq further revealed that the Hippo signaling, cell adhesion, and axon guidance pathways were involved in the response to an I. scapularis bite in humans. Features of the host response in these individuals also overlapped with that of laboratory guinea pigs exposed to I. scapularis and which acquired resistance to ticks. These findings offer novel insights for the development of new biomarkers for I. scapularis exposure and anti-tick vaccines for human use.

Relationship between circulating mitochondrial DNA and microRNA in patients with major depression

BACKGROUND

MicroRNAs (miRNAs) and circulating cell-free mitochondrial DNA (ccf-mtDNA) have attracted interest as biological markers of affective disorders. In response to stress, it is known that miRNAs in mitochondria diffuse out of the cytoplasm alongside mtDNA; however, this process has not yet been identified. We hypothesized that miRNAs derived from specific cell nuclei cause mitochondrial damage and mtDNA fragmentation under MDD-associated stress conditions.

METHODS

A comprehensive analysis of the plasma miRNA levels and quantification of the plasma ccf-mtDNA copy number were performed in 69 patients with depression to determine correlations and identify genes and pathways interacting with miRNAs. The patients were randomly assigned to receive either selective serotonin reuptake inhibitors (SSRI) or mirtazapine. Their therapeutic efficacy over four weeks was evaluated in relation to miRNAs correlated with ccf-mtDNA copy number.

RESULTS

The expression levels of the five miRNAs showed a significant positive correlation with the ccf-mtDNA copy number after correcting for multiple testing. These miRNAs are involved in gene expression related to thyroid hormone synthesis, the Hippo signaling pathway, vasopressin-regulated water reabsorption, and lysine degradation. Of these five miRNAs, miR-6068 and miR-4708-3p were significantly associated with the SSRI and mirtazapine treatment outcomes, respectively.

LIMITATIONS

This study did not show comparison with a healthy group.

CONCLUSIONS

The expression levels of specific miRNAs were associated with ccf-mtDNA copy number in untreated depressed patients; moreover, these miRNAs were linked to antidepressant treatment outcomes. These findings are expected to lead to the elucidation of new pathological mechanism of depression.

Age-dependent transcriptomic profiles of leukocytes in pediatric population

Immunity at birth is considered immature. Following birth, our immune function is considered to grow and reach maturation over time. To obtain granular information of leukocyte functions and transcriptomic profiles in pediatric cohort, we examined leukocyte profiles in infants, preschool and school children using single cell RNA sequencing of their peripheral blood mononuclear cells (PBMCs). Monocytes and natural killer (NK) cells showed immaturity in infants. Their innate and adaptive immunity was developed by preschool age. Adaptive immune cells showed different maturation patterns. CD4, CD8 naïve T cells and plasma cells continued to mature untill school age. In CD8 naïve T cells, innate immunity was upregulated in infants, in support of our knowledge that they manifests more innate cell-like phenotype soon after birth. Many signaling pathways have been differentially up- and/or down-regulated in infants, preschool and school children. Their contribution to the development of the immune system needs to be delineated.

Hippo Pathway Activation in Aged Mesenchymal Stem Cells Contributes to the Dysregulation of Hepatic Inflammation in Aged Mice

Aging is always accompanied by chronic diseases which probably attribute to long-term chronic inflammation in the aging body. Whereas, the mechanism of chronic inflammation in aging body is still obscure. Mesenchymal stem cells (MSCs) are capable of local chemotaxis to sites of inflammation and play a powerful role in immune regulation. Whether degeneration of MSCs in the aging body is associated with unbalanced inflammation is still not clear. In this study, immunosuppressive properties of aged MSCs are found to be repressed. The impaired immunosuppressive function of aged MSCs is associated with lower expression of the Hippo effector Yes-associated protein 1 (YAP1) and its target gene signal transducer and activator of transcription 1 (STAT1). YAP1 regulates the transcription of STAT1 through binding with its promoter. In conclusion, a novel YAP1/STAT1 axis maintaining immunosuppressive function of MSCs is revealed and impairment of this signal pathway in aged MSCs probably resulted in higher inflammation in aged mice liver.

Low MST1/2 and negative LATS1/2 expressions are associated with poor prognosis of colorectal cancers

Mammalian STe20-like protein kinase 1/2 (MST1/2) and large tumor suppressor homolog 1/2 (LATS1/2) are the core components of the tumor-suppressive Hippo pathway. Dysregulation of this pathway is associated with the progression and metastasis of various cancers. However, MST1/2 and LATS1/2 expressions have not been systematically evaluated in colorectal cancers. We evaluated the clinicopathologic correlation and prognostic significance of MST1/2 and LATS1/2 immunohistochemical expressions in 327 colorectal cancer patients. Low MST1/2 expression, identified in 235 (71.9 %) cases, was significantly associated with poor differentiation (P = 0.018) and large size (P < 0.001) of the tumor. Negative LATS1/2 expression, identified in 226 (69.1 %) cases, was significantly correlated with low MST1/2 expression (P = 0.044). Low MST1/2 and negative LATS1/2 expressions were significantly associated with poor overall survivals (P = 0.015 and P = 0.038, respectively). Furthermore, the combined MST1/2lowLATS1/2negative expression group showed significantly worse overall survival than other groups (P = 0.003), and considered as an independent poor prognostic factor for colorectal cancer patients (hazard ratio = 1.720; 95 % confidence interval, 1.143-2.588; P = 0.009). Low MST1/2 and negative LATS1/2 expressions may serve as prognostic indicators in patients with colorectal cancer.

The role of Hippo pathway in ovarian development

The follicle is the functional unit of the ovary, whereby ovarian development is largely dependent on the development of the follicles themselves. The activation, growth, and progression of follicles are modulated by a diverse range of factors, including reproductive endocrine system and multiple signaling pathways. The Hippo pathway exhibits a high degree of evolutionary conservation between both Drosophila and mammalian systems, and is recognized for its pivotal role in regulating cellular proliferation, control of organ size, and embryonic development. During the process of follicle development, the components of the Hippo pathway show temporal and spatial variations. Recent clinical studies have shown that ovarian fragmentation can activate follicles. The mechanism is that the mechanical signal of cutting triggers actin polymerization. This process leads to the disruption of the Hippo pathway and subsequently induces the upregulation of downstream CCN and apoptosis inhibitors, thereby promoting follicle development. Thus, the Hippo pathway plays a crucial role in both the activation and development of follicles. In this article, we focused on the development and atresia of follicles and the function of Hippo pathway in these processes. Additionally, the physiological effects of Hippo pathway in follicle activation are also explored.

MicroRNA profiling of cerebrospinal fluid from dogs with steroid responsive meningitis-arteritis and meningoencephalitis of unknown origin

Introduction

Non-infectious inflammatory diseases of the central nervous system in dogs, such as steroid responsive meningitis-arteritis (SRMA) and meningoencephalitis of unknown origin (MUO), represent a common clinical challenge that needs extensive and multimodal work-up to reach a presumptive diagnosis. Both diseases are presumably caused by dysregulations of the immune system, but further research is needed in order to understand the molecular mechanisms behind each disease and to optimize treatment.

Methods

By next-generation sequencing and subsequent quantitative real-time PCR (qPCR) verification, we designed a prospective case-control pilot study to analyze the small RNA profiles of cerebrospinal fluid from dogs suffering from MUO (N = 5), dogs suffering from SRMA (N = 8), and healthy dogs (N = 5) presented for elective euthanasia used as the Control group.

Results

Our results showed an overall enrichment in Y-RNA fragments across all samples, followed by microRNAs (miRNAs) and ribosomal RNAs as the major findings. Additional traces of short RNA reads mapped to long non-coding RNAs and protein-coding genes were also found. From the detected canine miRNAs, miR-21, miR-486, miR-148a, miR-99a, miR-191 and miR-92a were among the most abundant. Dogs with SRMA showed higher differences in miRNA abundance than dogs with MUO when compared to healthy dogs, and miR-142-3p was consistently detected as differentially upregulated in both diseases, although at a low concentration. Moreover, miR-405-5p and miR-503-5p showed different profiles between SRMA and MUO dogs. Subsequent qPCR analyses confirmed miR-142-5p, miR-191-5p and miR-92a-3p as significantly upregulated miRNAs in dogs with SRMA and/or MUO.

Discussion

Cerebrospinal fluid is a challenging biological material to use for profiling miRNAs due to the low content of circulating RNAs. Despite this, we could confirm several miRNAs being differentially abundant when comparing healthy dogs and dogs with MUO and SRMA, respectively. The results of this study indicate a potential role of miRNAs in the underlying molecular mechanisms of these diseases and establish the basis for further studies.

Mechanosensation to inflammation: Roles for YAP/TAZ in innate immune cells

Innate immune cells are responsible for eliminating foreign infectious agents and cellular debris, and their ability to perceive, respond to, and integrate biochemical and mechanical cues from their microenvironment eventually determines their behavior. In response to tissue injury, pathogen invasion, or a biomaterial implant, immune cells activate many pathways to initiate inflammation in the tissue. In addition to common inflammatory pathways, studies have demonstrated the role of the mechanosensitive proteins and transcriptional coactivators YAP and TAZ (YAP/TAZ) in inflammation and immunity. We review our knowledge of YAP/TAZ in controlling inflammation and immunity in innate immune cells. Furthermore, we discuss the roles of YAP/TAZ in inflammatory diseases, wound healing, and tissue regeneration and how they integrate mechanical cues with biochemical signaling during disease progression. Last, we comment on possible approaches that can be exploited to harness the therapeutic potential of YAP/TAZ in inflammatory diseases.

The hippo kinases MST1/2 in cardiovascular and metabolic diseases: A promising therapeutic target option for pharmacotherapy

Cardiovascular diseases (CVDs) and metabolic disorders are major components of noncommunicable diseases, causing an enormous health and economic burden worldwide. There are common risk factors and developmental mechanisms among them, indicating the far-reaching significance in exploring the corresponding therapeutic targets. MST1/2 kinases are well-established proapoptotic effectors that also bidirectionally regulate autophagic activity. Recent studies have demonstrated that MST1/2 influence the outcome of cardiovascular and metabolic diseases by regulating immune inflammation. In addition, drug development against them is in full swing. In this review, we mainly describe the roles and mechanisms of MST1/2 in apoptosis and autophagy in cardiovascular and metabolic events as well as emphasis on the existing evidence for their involvement in immune inflammation. Moreover, we summarize the latest progress of pharmacotherapy targeting MST1/2 and propose a new mode of drug combination therapy, which may be beneficial to seek more effective strategies to prevent and treat CVDs and metabolic disorders.

Integrated mRNA and miRNA expression analyses for Cryptocaryon irritans resistance in large yellow croaker (Larimichthys crocea)

Large yellow croaker (Larimichthys crocea) is one of the most important mariculture fish in China. However, cryptocaryonosis caused by Cryptocryon irritans infection has brought huge economic losses and threatened the healthy and sustainable development of L. crocea industry. Recently, a new C. irritans resistance strain of L. crocea (RS) has been bred using genomic selection technology in our laboratory work. However, the molecular mechanisms for C. irritans resistance of RS have not been fully understood. MicroRNAs (miRNAs) are endogenous small non-coding RNAs that are post-transcriptional regulators, and they play vital roles in immune process of bony fish. Identification of anti-C.irritans relevant miRNA signatures could, therefore, be of tremendous translational value. In the present study, integrated mRNA and miRNA expression analysis was used to explore C. irritans resistance mechanisms of the L. crocea. RS as well as a control strain (CS) of L. crocea, were artificially infected with C. irritans for 100 h, and their gill was collected at 0 h (pre-infection), 24 h (initial infection), and 72 h (peak infection) time points. The total RNA from gill tissues was extracted and used for transcriptome sequencing and small RNA sequencing. After sequencing, 23,172 known mRNAs and 289 known miRNAs were identified. The differential expression was analyzed in these mRNAs and mRNAs and the interactions of miRNA-mRNA pairs were constructed. KEGG pathway enrichment analyses showed that these putative target mRNAs of differentially expressed miRNAs (DEMs) were enriched in different immune-related pathways after C. irritans infection in RS and CS. Among them, necroptosis was the immune-related pathway that was only significantly enriched at two infection stages of RS group (RS-24 h/RS-0h and RS-72 h/RS-0h). Further investigation indicates that necroptosis may be activated by DEMs such as miR-133a-3p, miR-142a-3p and miR-135c, this promotes inflammation responses and pathogen elimination. These DEMs were selected as miRNAs that could potentially regulate the C. irritans resistance of L. crocea. Though these inferences need to be further verified, these findings will be helpful for the research of the molecular mechanism of C. irritans resistance of L. crocea and miRNA-assisted molecular breeding of aquatic animals.

MST1: A future novel target for cardiac diseases

Major heart diseases pose a serious threat to human health. Finding early diagnostic markers and key therapeutic targets is an urgent scientific problem in this field. Mammalian sterile 20-like kinase 1 (MST1) is a protein kinase, and the occurrence of many heart diseases is related to the continuous activation of the MST1 gene. With the deepening of the research, the potential role of MST1 in promoting the development of heart disease has become more apparent. Therefore, to better understand the role of MST1 in the pathogenesis of heart disease, this work systematically summarizes the role of MST1 in the pathogenesis of heart disease, gives a comprehensive overview of its possible strategies in the diagnosis and treatment of heart disease, and analyzes its potential significance as a marker for the diagnosis and treatment of heart disease.

CeRNA network identified hsa-miR-17-5p, hsa-miR-106a-5p and hsa-miR-2355-5p as potential diagnostic biomarkers for tuberculosis

This study aims to analyze the regulatory non-coding RNAs in the pathological process of tuberculosis (TB), and identify novel diagnostic biomarkers. A longitudinal study was conducted in 5 newly diagnosed pulmonary tuberculosis patients, peripheral blood samples were collected before and after anti-TB treatment for 6 months, separately. After whole transcriptome sequencing, the differentially expressed RNAs (DE RNAs) were filtrated with |log2 (fold change) | > log2(1.5) and P value < .05 as screening criteria. Then functional annotation was actualized by gene ontology enrichment analysis, and enrichment pathway analysis was conducted by Kyoto Encyclopedia of Genes and Genomes database. And finally, the competitive endogenous RNA (ceRNA) regulatory network was established according to the interaction of ceRNA pairs and miRNA-mRNA pairs. Five young women were recruited and completed this study. Based on the differential expression analysis, a total of 1469 mRNAs, 996 long non-coding RNAs, 468 circular RNAs, and 86 miRNAs were filtrated as DE RNAs. Functional annotation demonstrated that those DE-mRNAs were strongly involved in the cellular process (n = 624), metabolic process (n = 513), single-organism process (n = 505), cell (n = 651), cell part (n = 650), organelle (n = 569), and binding (n = 629). Enrichment pathway analysis revealed that the differentially expressed genes were mainly enriched in HTLV-l infection, T cell receptor signaling pathway, glycosaminoglycan biosynthesis-heparan sulfate/heparin, and Hippo signaling pathway. CeRNA networks revealed that hsa-miR-17-5p, hsa-miR-106a-5p and hsa-miR-2355-5p might be regarded as potential diagnostic biomarkers for TB. Immunomodulation-related genes are differentially expressed in TB patients, and hsa-miR-106a-5p, hsa-miR-17-5p, hsa-miR-2355-5p might serve as potential diagnostic biomarkers.

Gene expression in Verson's glands of the fall armyworm suggests their role in molting and immunity

Verson's glands are segmental pairs of dermal glands attached to the epidermis in lepidopteran larvae. They produce macromolecules during intermolt period and empty them during each molt. Morphological, histochemical, developmental, and protein analysis studies have been conducted to determine the functions of Verson's glands. However, the exact role of Verson's glands remains unclear. In our previous study, a strain of transgenic fall armyworm, Spdoptera frugiperda expressing green fluorescence protein (GFP) and Systemic RNA interference defective protein 1 (SID1) from Caenorhabditis elegans was established to improve RNA interference (RNAi) efficiency. Unexpectedly, we found that GFP fluorescence was significantly brighter in Verson's glands than in other tissues. Also, RNAi efficiency improved more in Verson's glands than in other tissues. We took advantage of improved RNAi efficiency to explore the function of Verson's glands. RNA-seq analysis revealed that genes highly expressed in Verson's glands code for cuticular proteins, molting fluid proteins, hemolymph proteins, and antimicrobial peptides. Injection of dsRNA targeting essential genes, inhibitor of apoptosis (IAP), Actin, and vacuolar-type ATPase (VATPase) interfered with Verson's glands growth. These results revealed that Verson's glands may contribute to hemolymph, cuticle, molting fluid, and immune response during molting. This study also provide useful tools for future research in identifying the physiological role of Verson's glands in lepidopteran insects.

Hippo pathway dysregulation in gastric cancer: from Helicobacter pylori infection to tumor promotion and progression

The Hippo pathway plays a critical role for balancing proliferation and differentiation, thus regulating tissue homeostasis. The pathway acts through a kinase cascade whose final effectors are the Yes-associated protein (YAP) and its paralog transcriptional co‑activator with PDZ‑binding motif (TAZ). In response to a variety of upstream signals, YAP and TAZ activate a transcriptional program that modulates cellular proliferation, tissue repair after injury, stem cell fate decision, and cytoskeletal reorganization. Hippo pathway signaling is often dysregulated in gastric cancer and in Helicobacter pylori-induced infection, suggesting a putative role of its deregulation since the early stages of the disease. In this review, we summarize the architecture and regulation of the Hippo pathway and discuss how its dysregulation fuels the onset and progression of gastric cancer. In this setting, we also focus on the crosstalk between Hippo and other established oncogenic signaling pathways. Lastly, we provide insights into the therapeutic approaches targeting aberrant YAP/TAZ activation and discuss the related clinical perspectives and challenges.

Possible Future Avenues for Rheumatoid Arthritis Therapeutics: Hippo Pathway

Rheumatoid arthritis (RA) is a persistent systemic autoimmune disease with the hallmarks of swelling of the joint, joint tenderness, and progressive joint destruction, which may cause synovial inflammation and pannus as a basic pathological change, resulting in joint malformations and serious disorders. At present, the precise etiology and mechanism of pathogenesis of RA are unknown. The imbalance of immune homeostasis is the origin of RA. Hippo pathway is widely expressed in a range of cell lineages and plays a fundamental role in maintaining the immune steady state and may be involved in the pathogenic mechanism of RA. This study reviews the progress of Hippo pathway and its main members in the pathogenesis of RA from three aspects: regulating the maintenance of autoimmune homeostasis, promoting the pathogenicity of synovial fibroblasts and regulating the differentiation of osteoclasts. The study also presents a new way to recognize the pathogenesis of rheumatoid arthritis, which is favorable for finding a new way for treating the rheumatoid arthritis.

Hippo dictates signaling for cellular homeostasis and immune defense in Crassostrea hongkongensis hemocytes

Introduction

The Hippo signaling pathway is an evolutionarily conserved signaling cascade that plays a crucial role in regulating cell proliferation, differentiation, and apoptosis. It has been shown to be a key regulator of cell fate and cellular homeostasis in various immune processes. Despite its well-established functions in vertebrate immunity, its roles in marine invertebrate immunity remain poorly understood. Therefore, our present work provides fresh mechanistic insights into how the Hippo pathway orchestrates hemocytic functions in Crassostrea hongkongensis, with implications for studies on its major forms and modifications in animal evolution.

Method

The complete set of Hippo pathway genes, including SAV1, MOB1, LATS, YAP/TAZ, TEAD, and MST, were identified from the C. hongkongensis genome. Quantitative PCR assays were conducted to examine the mRNA expression levels of these genes in different tissues and the levels of these genes in hemocytes before and after bacterial challenges. The study also examined the crosstalk between the Hippo pathway and other immune pathways, such as the AP-1 and p53-dependent p21 signaling cascades. RNA interference was used to knock down MST and TEAD, and MST is a core orchestrator of non-canonical Hippo signaling, to investigate its impact on phagocytosis and bacterial clearance in hemocytes.

Result

The results demonstrated that members of the Hippo pathway were highly expressed in hemocytes, with their expression levels significantly increasing following bacterial challenges. Crosstalk between the Hippo pathway and other immune pathways triggered hemocytic apoptosis, which functioned similarly to the canonical Mst-Lats-Yap signaling pathway in Drosophila and mammals. Knocking down MST resulted in increased phagocytosis and boosted the efficiency of bacterial clearance in hemocytes, presumably due to mobilized antioxidant transcription by Nrf for maintaining immune homeostasis.

Discussion

This study provides novel insights into the regulatory mechanisms underlying the Hippo pathway in immune responses of C. hongkongensis hemocytes. The study highlights the importance of the Hippo pathway in maintaining immune homeostasis and orchestrating hemocytic functions in oysters. Moreover, this study demonstrates the divergence of the Hippo pathway's roles in marine invertebrate immunity from mammalian observations, indicating the need for further comparative studies across species. These findings have significant implications for future research aimed at elucidating the evolutionary trajectory and functional diversity of the Hippo signaling pathway in animal evolution.

The Hippo signalling pathway and its implications in human health and diseases

As an evolutionarily conserved signalling network, the Hippo pathway plays a crucial role in the regulation of numerous biological processes. Thus, substantial efforts have been made to understand the upstream signals that influence the activity of the Hippo pathway, as well as its physiological functions, such as cell proliferation and differentiation, organ growth, embryogenesis, and tissue regeneration/wound healing. However, dysregulation of the Hippo pathway can cause a variety of diseases, including cancer, eye diseases, cardiac diseases, pulmonary diseases, renal diseases, hepatic diseases, and immune dysfunction. Therefore, therapeutic strategies that target dysregulated Hippo components might be promising approaches for the treatment of a wide spectrum of diseases. Here, we review the key components and upstream signals of the Hippo pathway, as well as the critical physiological functions controlled by the Hippo pathway. Additionally, diseases associated with alterations in the Hippo pathway and potential therapies targeting Hippo components will be discussed.

Critical role of PAFR/YAP1 positive feedback loop in cardiac fibrosis

Aberrant activation of cardiac fibroblasts is the main cause and character of cardiac fibrosis, and inhibition of cardiac fibrosis becomes a promising treatment for cardiac diseases. Platelet-activating factor (PAF) and Hippo pathway is recently recognized as key signaling mechanisms in cardiovascular diseases. In this study we explored the potential roles of PAF and Hippo signaling pathway in cardiac fibrosis. Myocardial infarction (MI) was induced in mice by left anterior descending artery ligation. After 28 days, the mice were sacrificed, and the hearts were collected for analyses. We showed that PAF receptor (PAFR) and yes-associated protein 1 (YAP1, a key effector in the Hippo pathway) were significantly increased in the heart of MI mice. Increased expression of PAFR and YAP1 was also observed in angiotensin II (Ang II)-treated mouse cardiac fibroblasts. In mouse cardiac fibroblasts, forced expression of YAP1 increased cell viability, resulted in collagen deposition and promoted fibroblast-myofibroblast transition. We showed that PAF induced fibrogenesis through activation of YAP1 and promoted its nuclear translocation via interacting with PAFR, while YAP1 promoted the expression of PAFR by binding to and activating transcription factor TEAD1. More importantly, silencing PAFR or YAP1 by shRNA, or using transgenic mice to induce the conditional deletion of YAP1 in cardiac fibroblasts, impeded cardiac fibrosis and improved cardiac function in MI mice. Taken together, this study elucidates the role and mechanisms of PAFR/YAP1 positive feedback loop in cardiac fibrosis, suggesting a potential role of this pathway as novel therapeutic targets in cardiac fibrosis.

CircRNA-regulated immune responses of asian honey bee workers to microsporidian infection

Nosema ceranae is a widespread fungal parasite for honey bees, causing bee nosemosis. Based on deep sequencing and bioinformatics, identification of circular RNAs (circRNAs) in Apis cerana workers’ midguts and circRNA-regulated immune response of host to N. ceranae invasion were conducted in this current work, followed by molecular verification of back-splicing sites and expression trends of circRNAs. Here, 10185 and 7405 circRNAs were identified in the midguts of workers at 7 days (AcT1) and 10 days (AcT2) post inoculation days post-inoculation with N. ceranae. PCR amplification result verified the back-splicing sites within three specific circRNAs (novel_circ_005123, novel_circ_007177, and novel_circ_015140) expressed in N. ceranae-inoculated midgut. In combination with transcriptome data from corresponding un-inoculated midguts (AcCK1 and AcCK2), 2266 circRNAs were found to be shared by the aforementioned four groups, whereas the numbers of specific ones were 2618, 1917, 5691, and 3723 respectively. Further, 83 52) differentially expressed circRNAs (DEcircRNAs) were identified in AcCK1 vs. AcT1 (AcCK2 vs. AcT2) comparison group. Source genes of DEcircRNAs in workers’ midgut at seven dpi were involved in two cellular immune-related pathways such as endocytosis and ubiquitin mediated proteolysis. Additionally, competing endogenous RNA (ceRNA) network analysis showed that 23 13) DEcircRNAs in AcCK1 vs. AcT1 (AcCK2 vs. AcT2) comparison group could target 18 14) miRNAs and further link to 1111 (1093) mRNAs. These target mRNAs were annotated to six cellular immunity pathways including endocytosis, lysosome, phagosome, ubiquitin mediated proteolysis, metabolism of xenobiotics by cytochrome P450, and insect hormone biosynthesis. Moreover, 284 164) internal ribosome entry site and 54 26) ORFs were identified from DEcircRNAs in AcCK1 vs. AcT1 (AcCK2 vs. AcT2) comparison group; additionally, ORFs in DEcircRNAs in midgut at seven dpi with N. ceranae were associated with several cellular immune pathways including endocytosis and ubiquitin-mediated proteolysis. Ultimately, RT-qPCR results showed that the expression trends of six DEcircRNAs were consistent with those in transcriptome data. These results demonstrated that N. ceranae altered the expression pattern of circRNAs in A. c. cerana workers’ midguts, and DEcircRNAs were likely to regulate host cellular and humoral immune response to microsporidian infection. Our findings lay a foundation for clarifying the mechanism underlying host immune response to N. ceranae infection and provide a new insight into interaction between Asian honey bee and microsporidian.

Exploration of the regulatory mechanisms of regeneration, anti-oxidation, anti-aging and the immune response at the post-molt stage of Eriocheir sinensis

Eriocheir sinensis is widely appreciated by the surrounding population due to its culinary delicacy and rich nutrients. The E. sinensis breeding industry is very prosperous and molting is one of the important growth characteristics. Research on the regulation of molting in E. sinensis is still in the initial stages. There is currently no relevant information on the regulatory mechanisms of heart development following molting. Comparative transcriptome analysis was used to study developmental regulation mechanisms in the heart of E. sinensis at the post-molt and inter-molt stages. The results indicated that many regulatory pathways and genes involved in regeneration, anti-oxidation, anti-aging and the immune response were significantly upregulated after molting in E. sinensis. Aside from cardiac development, the differentially expressed genes (DEGs) were relevant to myocardial movement and neuronal signal transduction. DEGs were also related to the regulation of glutathione homeostasis and biological rhythms in regard to anti-oxidation and anti-aging, and to the regulation of immune cell development and the immune response. This study provides a theoretical framework for understanding the regulation of molting in E. sinensis and in other economically important crustaceans.

Computational Analysis of Short Linear Motifs in the Spike Protein of SARS-CoV-2 Variants Provides Possible Clues into the Immune Hijack and Evasion Mechanisms of Omicron Variant

Short linear motifs (SLiMs) are short linear sequences that can mediate protein–protein interaction. Mimicking eukaryotic SLiMs to compete with extra- or intracellular binding partners, or to sequester host proteins is the crucial strategy of viruses to pervert the host system. Evolved proteins in viruses facilitate minimal protein–protein interactions that significantly affect intracellular signaling networks. Unfortunately, very little information about SARS-CoV-2 SLiMs is known, especially across SARS-CoV-2 variants. Through the ELM database-based sequence analysis of spike proteins from all the major SARS-CoV-2 variants, we identified four overriding SLiMs in the SARS-CoV-2 Omicron variant, namely, LIG_TRFH_1, LIG_REV1ctd_RIR_1, LIG_CaM_NSCaTE_8, and MOD_LATS_1. These SLiMs are highly likely to interfere with various immune functions, interact with host intracellular proteins, regulate cellular pathways, and lubricate viral infection and transmission. These cellular interactions possibly serve as potential therapeutic targets for these variants, and this approach can be further exploited to combat emerging SARS-CoV-2 variants.

The effect of AKT in extracellular matrix stiffness induced osteogenic differentiation of hBMSCs

Extracellular matrix (ECM) stiffness is an important biophysical factor in human bone marrow mesenchymal stem cells (hBMSCs) differentiation. Although there is evidence that Yes-associated protein (YAP) plays an important role in ECM elasticity induced osteogenesis, but the regulatory mechanism and signaling pathways have not been distinctly uncovered. In this study, hBMSCs were cultured on collagen-coated polydimethylsiloxane hydrogels with stiffness corresponding to Young's moduli of 0.5 kPa and 32 kPa, and gene chip analyses revealed the phosphoinositide 3-kinase (PI3K)-AKT pathway was highly correlated with ECM stiffness. Following western blots indicated that AKT phosphorylation was evidently affected in 5th-7th days after ECM stiffness stimulation, while PI3K showed little difference. The AKT activator SC79 and inhibitor MK2206 were utilized to modulate AKT phosphorylation. SC79 and MK2206 caused alteration in the mRNA expression and protein level of alkaline phosphatase (ALP), collagen type I alpha 1 (COL1A1) and runt related transcription factor 2 (RUNX2). On 32 kPa substrates, YAP enrichment in nucleus were significantly promoted by SC79 and remarkably decreased by MK2206. Besides, the ratio of YAP/p-YAP is upregulated by SC79 on both 32 kPa and 0.5 kPa substrates. In conclusion, these findings suggest that AKT is involved in the modulation of ECM stiffness induced osteogenesis, and AKT phosphorylation also influences the subcellular localization and activation of YAP.

Emerging roles of the Hippo signaling pathway in modulating immune response and inflammation-driven tissue repair and remodeling

Inflammation is an evolutionarily conserved process and part of the body's defense mechanism. Inflammation leads to the activation of immune and non-immune cells that protect the host tissue/organs from injury or intruding pathogens. The Hippo pathway is an evolutionarily conserved kinase cascade with an established role in regulating cell proliferation, survival, and differentiation. It is involved in diverse biological processes, including organ size control and tissue homeostasis. Recent clinical and pre-clinical studies have shown that the Hippo signaling pathway is also associated with injury- and pathogen-induced tissue inflammation and associated immunopathology. In this review, we have summarized the recent findings related to the involvement of the Hippo signaling pathway in modulating the immune response in different acute and chronic inflammatory diseases and its impact on tissue repair and remodeling.

Novel feature selection method via kernel tensor decomposition for improved multi-omics data analysis

Background

Feature selection of multi-omics data analysis remains challenging owing to the size of omics datasets, comprising approximately \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10^2$$\end{document}102–\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$10^5$$\end{document}105 features. In particular, appropriate methods to weight individual omics datasets are unclear, and the approach adopted has substantial consequences for feature selection. In this study, we extended a recently proposed kernel tensor decomposition (KTD)-based unsupervised feature extraction (FE) method to integrate multi-omics datasets obtained from common samples in a weight-free manner.

Method

KTD-based unsupervised FE was reformatted as the collection of kernelized tensors sharing common samples, which was applied to synthetic and real datasets.

Results

The proposed advanced KTD-based unsupervised FE method showed comparative performance to that of the previously proposed KTD method, as well as tensor decomposition-based unsupervised FE, but required reduced memory and central processing unit time. Moreover, this advanced KTD method, specifically designed for multi-omics analysis, attributes P values to features, which is rare for existing multi-omics–oriented methods.

Conclusions

The sample R code is available at https://github.com/tagtag/MultiR/.

Transcriptome Differences in Normal Human Bronchial Epithelial Cells in Response to Influenza A pdmH1N1 or H7N9 Virus Infection

Avian influenza A (H7N9) virus infections frequently lead to acute respiratory distress syndrome and death in humans. The emergence of H7N9 virus infections is a serious public health threat. To identify virus–host interaction differences between the highly virulent H7N9 and pandemic influenza H1N1 (pdmH1N1), RNA sequencing was performed of normal human bronchial epithelial (NHBE) cells infected with either virus. The transcriptomic analysis of host cellular responses to viral infection enables the identification of potential cellular factors related to infection. Significantly different gene expression patterns were found between pdmH1N1- and H7N9-infected NHBE cells. In addition, the H7N9 virus infection induced strong immune responses, while cellular repair mechanisms were inhibited. The differential expression of specific factors observed between avian H7N9 and pdmH1N1 influenza virus strains can account for variations in disease pathogenicity. These findings provide a framework for future studies examining the molecular mechanisms underlying the pathogenicity of avian H7N9 virus.

Gene expression in Lucilia sericata (Diptera: Calliphoridae) larvae exposed to Pseudomonas aeruginosa and Acinetobacter baumannii identifies shared and microbe-specific induction of immune genes

Antibiotic resistance is a continuing challenge in medicine. There are various strategies for expanding antibiotic therapeutic repertoires, including the use of blow flies. Their larvae exhibit strong antibiotic and antibiofilm properties that alter microbiome communities. One species, Lucilia sericata, is used to treat problematic wounds due to its debridement capabilities and its excretions and secretions that kill some pathogenic bacteria. There is much to be learned about how L. sericata interacts with microbiomes at the molecular level. To address this deficiency, gene expression was assessed after feeding exposure (1 h or 4 h) to two clinically problematic pathogens: Pseudomonas aeruginosa and Acinetobacter baumannii. The results identified immunity-related genes that were differentially expressed when exposed to these pathogens, as well as non-immune genes possibly involved in gut responses to bacterial infection. There was a greater response to P. aeruginosa that increased over time, while few genes responded to A. baumannii exposure, and expression was not time-dependent. The response to feeding on pathogens indicates a few common responses and features distinct to each pathogen, which is useful in improving the wound debridement therapy and helps to develop biomimetic alternatives.

Yorkie Negatively Regulates the Expression of Antimicrobial Proteins by Inducing Cactus Transcription in Prawns Macrobrachium nipponense

The Hippo signaling pathway controls organ size and immune system in Drosophila and mammals. Yorkie acts as a transcriptional co-activator in the Hippo pathway and cross-talks with other essential pathways. In this study, a Yorkie gene and two Cactus isoforms (designated as MnYorkie, MnCactus-a, and MnCactus-b, respectively) were isolated and characterized from oriental river prawns (Macrobrachium nipponense). Results showed that MnYorkie includes 1620 bp open reading frame and encodes a protein of 539 amino acids (aa). MnCactus-a (377 aa) and MnCactus-b (471 aa) were produced by alternative splicing. MnYorkie and MnCactus were continuously expressed in all selected tissues. Upon Gram-positive bacterium Staphylococcus aureus and Gram-negative bacterium Vibrio parahaemolyticus stimulation, the mRNA levels of MnYorkie and MnCactus in hemocytes and intestines underwent time-dependent enhancement. RNA interference studies showed that MnYorkie silencing remarkably downregulated the transcription of MnCactus but upregulated the expression of seven immune-related genes. In addition, MnYorkie silencing in vivo decreased the susceptibility of prawns to bacterial challenge. After S. aureus and V. parahaemolyticus infection, the survival rate of prawns increased significantly from 2 to 6 days, which corresponded to the period of MnYorkie knockdown. All these findings suggested that MnYorkie in the Hippo pathway might exhibit remarkable biological roles in the immune defense of M. nipponense by negatively regulating the expression of immune-related genes and promoting the transcription of MnCactus.

Transcriptional Modulation of the Hippo Signaling Pathway by Drugs Used to Treat Bipolar Disorder and Schizophrenia

Recent reports suggest a link between positive regulation of the Hippo pathway with bipolar disorder (BD), and the Hippo pathway is known to interact with multiple other signaling pathways previously associated with BD and other psychiatric disorders. In this study, neuronal-like NT2 cells were treated with amisulpride (10 µM), aripiprazole (0.1 µM), clozapine (10 µM), lamotrigine (50 µM), lithium (2.5 mM), quetiapine (50 µM), risperidone (0.1 µM), valproate (0.5 mM), or vehicle control for 24 h. Genome-wide mRNA expression was quantified and analyzed using gene set enrichment analysis (GSEA), with genes belonging to Hippo, Wnt, Notch, TGF- β, and Hedgehog retrieved from the KEGG database. Five of the eight drugs downregulated the genes of the Hippo pathway and modulated several genes involved in the interacting pathways. We speculate that the regulation of these genes, especially by aripiprazole, clozapine, and quetiapine, results in a reduction of MAPK and NFκB pro-inflammatory signaling through modulation of Hippo, Wnt, and TGF-β pathways. We also employed connectivity map analysis to identify compounds that act on these pathways in a similar manner to the known psychiatric drugs. Thirty-six compounds were identified. The presence of antidepressants and antipsychotics validates our approach and reveals possible new targets for drug repurposing.

TEAD family transcription factors in development and disease

The balance between stem cell potency and lineage specification entails the integration of both extrinsic and intrinsic cues, which ultimately influence gene expression through the activity of transcription factors. One example of this is provided by the Hippo signalling pathway, which plays a central role in regulating organ size during development. Hippo pathway activity is mediated by the transcriptional co-factors Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), which interact with TEA domain (TEAD) proteins to regulate gene expression. Although the roles of YAP and TAZ have been intensively studied, the roles played by TEAD proteins are less well understood. Recent studies have begun to address this, revealing that TEADs regulate the balance between progenitor self-renewal and differentiation throughout various stages of development. Furthermore, it is becoming apparent that TEAD proteins interact with other co-factors that influence stem cell biology. This Primer provides an overview of the role of TEAD proteins during development, focusing on their role in Hippo signalling as well as within other developmental, homeostatic and disease contexts.

TLR4 signalling via Piezo1 engages and enhances the macrophage mediated host response during bacterial infection

TLR4 signaling plays key roles in the innate immune response to microbial infection. Innate immune cells encounter different mechanical cues in both health and disease to adapt their behaviors. However, the impact of mechanical sensing signals on TLR4 signal-mediated innate immune response remains unclear. Here we show that TLR4 signalling augments macrophage bactericidal activity through the mechanical sensor Piezo1. Bacterial infection or LPS stimulation triggers assembly of the complex of Piezo1 and TLR4 to remodel F-actin organization and augment phagocytosis, mitochondrion-phagosomal ROS production and bacterial clearance and genetic deficiency of Piezo1 results in abrogation of these responses. Mechanistically, LPS stimulates TLR4 to induce Piezo1-mediated calcium influx and consequently activates CaMKII-Mst1/2-Rac axis for pathogen ingestion and killing. Inhibition of CaMKII or knockout of either Mst1/2 or Rac1 results in reduced macrophage bactericidal activity, phenocopying the Piezo1 deficiency. Thus, we conclude that TLR4 drives the innate immune response via Piezo1 providing critical insight for understanding macrophage mechanophysiology and the host response.

YAP1 is a Prognostic Biomarker and Correlated with Immune Cell Infiltration in Pancreatic Cancer

Yes-associated protein-1 (YAP1) is an important effector of the Hippo pathway and has crosstalk with other cancer signaling pathways. It induces an immunosuppressive tumor microenvironment by activating pathways in several cellular components. However, the mechanisms by which it drives immune infiltration in pancreatic cancer remain poorly understood. We analyzed the expression of YAP1 as well as its prognostic value and correlations with immune infiltrates in various cancers, with a focus on pancreatic cancer. In particular, using the Oncomine database and Gene Expression Profiling Interactive Analysis (GEPIA) database, we found that YAP1 is differentially expressed between tumor tissues and control tissues in a number of cancers and in particular, is elevated in pancreatic cancer. Using the Kaplan–Meier plotter, GEPIA, and Long-term Outcome and Gene Expression Profiling database of pan-cancers (LOGpc), we further established the prognostic value of YAP1. We found that YAP1 expression was significantly related to outcomes in multiple types of cancer based on data from The Cancer Genome Atlas, particularly in pancreatic cancer. Correlations between YAP1 and immune cell infiltration and immune cell marker expression were examined using Tumor Immune Estimation Resource and GEPIA. High expression levels of YAP1 were significantly associated with a variety of immune markers and immune cell subsets in pancreatic cancer. These results suggest that YAP1 is correlated with patient outcomes and tumor immune cell infiltration in multiple cancer types and is a valuable prognostic biomarker in pancreatic cancer.

Fisetin Inhibits Osteogenic Differentiation of Mesenchymal Stem Cells via the Inhibition of YAP

Mesenchymal stem cells (MSCs) are self-renewal and capable of differentiating to various functional cell types, including osteocytes, adipocytes, myoblasts, and chondrocytes. They are, therefore, regarded as a potential source for stem cell therapy. Fisetin is a bioactive flavonoid known as an active antioxidant molecule that has been reported to inhibit cell growth in various cell types. Fisetin was shown to play a role in regulating osteogenic differentiation in animal-derived MSCs; however, its molecular mechanism is not well understood. We, therefore, studied the effect of fisetin on the biological properties of human MSCs derived from chorion tissue and its role in human osteogenesis using MSCs and osteoblast-like cells (SaOs-2) as a model. We found that fisetin inhibited proliferation, migration, and osteogenic differentiation of MSCs as well as human SaOs-2 cells. Fisetin could reduce Yes-associated protein (YAP) activity, which results in downregulation of osteogenic genes and upregulation of fibroblast genes. Further analysis using molecular docking and molecular dynamics simulations suggests that fisetin occupied the hydrophobic TEAD pocket preventing YAP from associating with TEA domain (TEAD). This finding supports the potential application of flavonoids like fisetin as a protein–protein interaction disruptor and also suggesting an implication of fisetin in regulating human osteogenesis.

YAP promotes the activation of NLRP3 inflammasome via blocking K27-linked polyubiquitination of NLRP3

The transcription coactivator YAP plays a vital role in Hippo pathway for organ-size control and tissue homeostasis. Recent studies have demonstrated YAP is closely related to immune disorders and inflammatory diseases, but the underlying mechanisms remain less defined. Here, we find that YAP promotes the activation of NLRP3 inflammasome, an intracellular multi-protein complex that orchestrates host immune responses to infections or sterile injuries. YAP deficiency in myeloid cells significantly attenuates LPS-induced systemic inflammation and monosodium urate (MSU) crystals-induced peritonitis. Mechanistically, YAP physically interacts with NLRP3 and maintains the stability of NLRP3 through blocking the association between NLRP3 and the E3 ligase β-TrCP1, the latter increases the proteasomal degradation of NLRP3 via K27-linked ubiquitination at lys380. Together, these findings establish a role of YAP in the activation of NLRP3 inflammasome, and provide potential therapeutic target to treat the NLRP3 inflammasome-related diseases.

Upregulation of KDM6B contributes to lipopolysaccharide-induced anxiety-like behavior via modulation of VGLL4 in mice

Histone H3K27me3 demethylase KDM6B (also known as Jumonji domain-containing protein D3, JMJD3) plays vital roles in the etiology of inflammatory responses; however, little is known about the role of KDM6B in neuroinflammation-induced anxiety-like behavior. The present study aimed to investigate the potential role of KDM6B in lipopolysaccharide (LPS)-induced anxiety-like behavior and to evaluate whether it is associated with the modulation of vestigial-like family member 4 (VGLL4). The elevated plus maze, light-dark box, and open-field test were performed to test the anxiety-like behavior induced by LPS in C57BL/6 J male mice. Levels of relative protein expression in the hippocampus were quantified by western blotting. KDM6B inhibitor GSK-J4 and microglia inhibitor minocycline as well as adeno-associated virus of Vgll4 shRNA were used to explore the underlying mechanisms. We found that KDM6B, VGLL4, interleukin-1β (IL-1β), and ionized calcium-binding adaptor molecule-1 (Iba-1, microglia marker) protein levels were increased in LPS-dose dependent manner in the hippocampus but not in prefrontal cortex. GSK-J4 treatment attenuated LPS-induced VGLL4, the signal transducer and activator of transcription 3 (STAT3), IL-1β and Iba-1 upregulation and anxiety-like behavior. Knockdown VGLL4 with Vgll4 shRNA prevented the increase of anxiety-like behavior and levels of STAT3, IL-1β, and Iba-1 expression in the hippocampus of LPS-treated mice. Moreover, minocycline, an inhibitor of microglia treatment blunted LPS-induced anxiety-like behavior. Collectively, these results demonstrate that the induction of neuroinflammation by LPS promotes KDM6B activation in the hippocampus, and LPS-induced anxiety-like behavior is associated with upregulation of VGLL4 by KDM6B in the hippocampus.

NF2 and Canonical Hippo-YAP Pathway Define Distinct Tumor Subsets Characterized by Different Immune Deficiency and Treatment Implications in Human Pleural Mesothelioma

Simple Summary

It is a long-held notion that loss-of-function mutations in negative regulators of the Hippo-YAP pathway, such as NF2, LATS1/2, have a similar potential to promote nuclear YAP activity, which is thought to play an essential role in the pathogenesis of MPM. Whether loss-of-function in these individual regulators uniformly affects the Hippo-YAP activity and contributes to a similar disease phenotype has not yet been revealed in MPM. Surprisingly and interestingly, we found in this study that loss-of-function in the upstream regulator NF2 of the Hippo pathway is linked to the aberrant activation of Hippo-YAP-independent signaling. More importantly, our work showed NF2 loss-of-function and dysregulated Hippo-YAP pathway define distinct MPM subsets that differ in molecular features, therapeutic implications, patients’ prognosis, and in particular, infiltrative immune signatures. Our findings in this study may be instrumental for the precise management of immunotherapy and/or targeted therapy for MPM patients.

Abstract

(1) Inactivation of the tumor suppressor NF2 is believed to play a major role in the pathogenesis of malignant pleural mesothelioma (MPM) by deregulating the Hippo-YAP signaling pathway. However, NF2 has functions beyond regulation of the Hippo pathway, raising the possibility that NF2 contributes to MPM via Hippo-independent mechanisms. (2) We performed weighted gene co-expression analysis (WGCNA) in transcriptomic and proteomic datasets obtained from The Cancer Gene Atlas (TCGA) MPM cohort to identify clusters of co-expressed genes highly correlated with NF2 and phospho (p)-YAP protein, surrogate markers of active Hippo signaling and YAP inactivation. The potential targets are experimentally validated using a cell viability assay. (3) MPM tumors with NF2 loss-of-function are not associated with changes in p-YAP level nor YAP/TAZ activity score, but are characterized by a deficient B-cell receptor (BCR) signaling pathway. Conversely, MPM tumors with YAP activation display exhausted CD8 T-cell-mediated immunity together with significantly upregulated PD-L1, which is validated in an independent MPM cohort, suggesting a potential benefit of immune-checkpoint inhibitors (ICI) in this patient subset. In support of this, mutations in core Hippo signaling components including LATS2, but not NF2, are independently associated with better overall survival in response to ICI in patients. Additionally, based on cancer cell line models, we show that MPM cells with a high Hippo-YAP activity are particularly sensitive to inhibitors of BCR-ABL/SRC, stratifying a unique MPM patient subset that may benefit from BCR-ABL/SRC therapies. Furthermore, we observe that NF2 physically interacts with a considerable number of proteins that are not involved in the canonical Hippo-YAP pathway, providing a possible explanation for its Hippo-independent role in MPM. Finally, survival analyses show that YAP/TAZ scores together with p-YAP protein level, but not NF2, predict the prognosis of MPM patients. (4) NF2 loss-of-function and dysregulated Hippo-YAP pathway define distinct MPM subsets that differ in their molecular features and prognosis, which has important clinical implications for precision oncology in MPM patients.

Suppression of Hippo Pathway by Food Allergen Exacerbates Intestinal Epithelia Instability and Facilitates Hypersensitivity

SCOPE

Hippo signaling is a crucial pathway in innate immune responses, but the relationship between food allergy and Hippo pathway is unknown. The aim of this work is to investigate the regulation of food allergy by Hippo pathway and reveal the molecular mechanisms.

METHODS AND RESULTS

Two food allergens tropomyosin and ovalbumin are used to challenge a mouse model and CMT93 intestinal epithelia cell model. The allergic responses and the activation of Hippo pathway are tested in these models. In the mouse model, both allergens trigged significant allergic responses, and Hippo pathway is suppressed after allergen challenge. In CMT93, both allergens upregulate the expression of allergic cytokines thymic stromal lymphopoietin, interleukin (IL)-25, and IL-33. In TAZ KD CMT93, the Hippo pathway is blocked, and the expression of allergenic cytokines are also suppressed.

CONCLUSIONS

Both in vivo and in vitro data demonstrate that the two food allergens suppressed Hippo pathway by downregulating TAZ expression, resulting in intestinal epithelia instability, and finally leading to hypersensitivity reactions. These findings provide potential therapeutic targets and molecular markers for food allergy, and provide dietary guidelines for allergenic individuals.

Hippo signaling: bridging the gap between cancer and neurodegenerative disorders

During development, regulation of organ size requires a balance between cell proliferation, growth and cell death. Dysregulation of these fundamental processes can cause a variety of diseases. Excessive cell proliferation results in cancer whereas excessive cell death results in neurodegenerative disorders. Many signaling pathways known-to-date have a role in growth regulation. Among them, evolutionarily conserved Hippo signaling pathway is unique as it controls both cell proliferation and cell death by a variety of mechanisms during organ sculpture and development. Neurodegeneration, a complex process of progressive death of neuronal population, results in fatal disorders with no available cure to date. During normal development, cell death is required for sculpting of an organ. However, aberrant cell death in neuronal cell population can result in neurodegenerative disorders. Hippo pathway has gathered major attention for its role in growth regulation and cancer, however, other functions like its role in neurodegeneration are also emerging rapidly. This review highlights the role of Hippo signaling in cell death and neurodegenerative diseases and provide the information on the chemical inhibitors employed to block Hippo pathway. Understanding Hippo mediated cell death mechanisms will aid in development of reliable and effective therapeutic strategies in future.

Immuno-hippo: Research progress of the hippo pathway in autoimmune disease

Extensive research in Drosophila and mammals has identified the core components of Hippo signaling, which controls gene expression. Studies of Drosophila have demonstrated the highly conserved Hippo pathway controls tissue homeostasis and organ size by regulating the balance between cell proliferation and apoptosis. Recent work has indicated a potential role of the Hippo pathway in regulating the immune system, which is the key player in autoimmune disease (AID). Therefore, the Hippo pathway may become a novel target for curing AID. Although the pivotal role of both the Hippo pathway in tumorigenesis has been thoroughly investigated, the role of it in AID is still poorly understood. Elucidating the role of Hippo signaling pathways in the activation and expression of specific molecules involved in immune regulation is important for understanding the pathogenesis of AID and exploring novel therapeutic targets. To aid in further research, this review describes the relationship between the Hippo pathway and inflammatory signals such as NF-κB and JAK-STAT, the function of the Hippo pathway in the formation and differentiation of immune cells, and the regulatory role of the Hippo pathway in AID.

Chromosomal genome of Triplophysa bleekeri provides insights into its evolution and environmental adaptation

BACKGROUND

Intense stresses caused by high-altitude environments may result in noticeable genetic adaptions in native species. Studies of genetic adaptations to high elevations have been largely limited to terrestrial animals. How fish adapt to high-elevation environments is largely unknown. Triplophysa bleekeri, an endemic fish inhabiting high-altitude regions, is an excellent model to investigate the genetic mechanisms of adaptation to the local environment. Here, we assembled a chromosomal genome sequence of T. bleekeri, with a size of ∼628 Mb (contig and scaffold N50 of 3.1 and 22.9 Mb, respectively). We investigated the origin and environmental adaptation of T. bleekeri based on 21,198 protein-coding genes in the genome.

RESULTS

Compared with fish species living at low altitudes, gene families associated with lipid metabolism and immune response were significantly expanded in the T. bleekeri genome. Genes involved in DNA repair exhibit positive selection for T. bleekeri, Triplophysa siluroides, and Triplophysa tibetana, indicating that adaptive convergence in Triplophysa species occurred at the positively selected genes. We also analyzed whole-genome variants among samples from 3 populations. The results showed that populations separated by geological and artificial barriers exhibited obvious differences in genetic structures, indicating that gene flow is restricted between populations.

CONCLUSIONS

These results will help us expand our understanding of environmental adaptation and genetic diversity of T. bleekeri and provide valuable genetic resources for future studies on the evolution and conservation of high-altitude fish species such as T. bleekeri.

Higher Incidence of B Cell Malignancies in Primary Immunodeficiencies: A Combination of Intrinsic Genomic Instability and Exocytosis Defects at the Immunological Synapse

Congenital defects of the immune system called primary immunodeficiency disorders (PID) describe a group of diseases characterized by a decrease, an absence, or a malfunction of at least one part of the immune system. As a result, PID patients are more prone to develop life-threatening complications, including cancer. PID currently include over 400 different disorders, however, the variety of PID-related cancers is narrow. We discuss here reasons for this clinical phenotype. Namely, PID can lead to cell intrinsic failure to control cell transformation, failure to activate tumor surveillance by cytotoxic cells or both. As the most frequent tumors seen among PID patients stem from faulty lymphocyte development leading to leukemia and lymphoma, we focus on the extensive genomic alterations needed to create the vast diversity of B and T lymphocytes with potential to recognize any pathogen and why defects in these processes lead to malignancies in the immunodeficient environment of PID patients. In the second part of the review, we discuss PID affecting tumor surveillance and especially membrane trafficking defects caused by altered exocytosis and regulation of the actin cytoskeleton. As an impairment of these membrane trafficking pathways often results in dysfunctional effector immune cells, tumor cell immune evasion is elevated in PID. By considering new anti-cancer treatment concepts, such as transfer of genetically engineered immune cells, restoration of anti-tumor immunity in PID patients could be an approach to complement standard therapies.