Cellular functions of programmed cell death 5

Sulfasalazine inhibits esophageal cancer cell proliferation by mediating ferroptosis

This study aimed to explore the potential mechanism by which sulfasalazine (SAS) inhibits esophageal cancer cell proliferation. A cell counting kit-8 (CCK-8) assay was used to detect the effect of SAS (0, 1, 2, and 4 mM) on the proliferation of TE-1 cells. Subsequently, TE-1 cells were divided into control group, SAS group, SAS + ferrostatin-1 (ferroptosis inhibitor) group, and SAS + Z-VAD (OH)-FMK (apoptosis inhibitor) group, and cell proliferation was measured using a CCK-8 assay. Real-time quantitative polymerase chain reaction and western blotting were used to determine the expression of solute carrier family member 7 11 (SLC7A11, also called xCT), glutathione peroxidase 4 (GPX4), and acyl-CoA synthase long-chain family member 4 (ACSL4) in TE-1 cells. Measurement of ferroptosis in TE-1 cells was achieved by flow cytometry. Compared with the control group (0 mM SAS), the proliferation of TE-1 cells was significantly inhibited by different concentrations of SAS for different time lengths, and 4 mM SAS treatment for 48 h could obtain the maximum inhibition rate (53.9%). In addition, SAS treatment caused a significant decrease in the mRNA and protein expression of xCT and GPX4, and a significant increase in ACSL4 expression in TE-1 cells treated with SAS. Flow cytometry results showed that the ferroptosis level was significantly increased after SAS treatment. However, the activation of ferroptosis by SAS was partially eliminated by treatment with ferrostatin-1 or Z-VAD (OH)-FMK. In conclusion, SAS inhibits the proliferation of esophageal carcinoma cells by activating the ferroptosis pathway.

PDCD5 as a Potential Biomarker for Improved Prediction of the Incidence and Remission for Patients with Rheumatoid Arthritis

INTRODUCTION

Rheumatoid arthritis (RA) often involves an altered T-cell subpopulation, higher levels of inflammatory cytokines, and auto-antibodies. This study investigated whether PDCD5 could be a biomarker to predict the incidence and remission of RA so as to guide the therapeutic management of clinical RA.

METHODS

One hundred fifty-two patients (41 being in both active status and stable remission status) who were newly diagnosed with RA and 38 healthy controls were enrolled. Basic clinical data were collected before using blood samples remaining in the clinic after routine complete blood count. The ability of PDCD5 and important indicators to predict the remission of RA was estimated based on receiver operating characteristic curve (ROC) analysis.

RESULTS

PDCD5 expression was found to be significantly increased in RA patients in active status in comparison with healthy controls or those in stable remission status. Compared with anti-CCP, ESR and DAS28 score, PDCD5 was of better predictive value with an AUC of 0.846 (95% CI 0.780-0.912) for RA remission. The incidence risk of RA increased with higher levels of PDCD5 (OR = 1.73, 95% CI = 1.45-1.98, P = 0.005) in multiple logistic regression analysis, with the risk increasing by 2.94-times for high-risk group in comparison with low-risk group (OR = 2.94, 95% CI = 2.35-4.62, P < 0.001). The association between PDCD5 and RA remission showed a similar result. For correlation analysis, significant associations were eventually found between PDCD5 and indicated genes (FOXP3, TNF-α, IL-17A, IFN-γ and IL-6) as well as several important clinical parameters including IgG, RF, CRP, ESR, anti-CCP and DAS28 score.

CONCLUSIONS

This study suggested that increased PDCD5 expression was significantly linked to the incidence and remission of RA. PDCD5 may be used as a novel biomarker for the prediction of RA incidence and remission, especially due to its potential involvement in the development of the condition.

Potential application of heat shock proteins as therapeutic targets in Parkinson's disease

Parkinson's disease (PD) is a common chronic neurodegenerative disease, and the heat shock proteins (HSPs) are proved to be of great value for PD. In addition, HSPs can maintain protein homeostasis, degrade and inhibit protein aggregation by properly folding and activating intracellular proteins in PD. This study mainly summarizes the important roles of HSPs in PD and explores their feasibility as targets. We introduced the structural and functional characteristics of HSPs and the physiological functions of HSPs in PD. HSPs can protect neurons from damage by degrading aggregates with three mechanisms, including the aggregation and removing α-Synuclein (α-Syn) aggregates, promotion the autophagy of abnormal proteins, and inhibition the apoptosis of degenerated neurons. This study underscores the importance of HSPs as targets in PD and helps to expand new mechanisms in PD treatment strategies.

Effects of Physiological and Pathological Urea Concentrations on Human Microvascular Endothelial Cells

Urea is the uremic toxin accumulating with the highest concentration in the plasma of chronic kidney disease (CKD) patients, not being completely cleared by dialysis. Urea accumulation is reported to exert direct and indirect side effects on the gastrointestinal tract, kidneys, adipocytes, and cardiovascular system (CVS), although its pathogenicity is still questioned since studies evaluating its side effects lack homogeneity. Here, we investigated the effects of physiological and pathological urea concentrations on a human endothelial cell line from the microcirculation (Human Microvascular Endothelial Cells-1, HMEC-1). Urea (5 g/L) caused a reduction in the proliferation rate after 72 h of exposure and appeared to be a potential endothelial-to-mesenchymal transition (EndMT) stimulus. Moreover, urea induced actin filament rearrangement, a significant increase in matrix metalloproteinases 2 (MMP-2) expression in the medium, and a significant up- or down-regulation of other EndMT biomarkers (keratin, fibrillin-2, and collagen IV), as highlighted by differential proteomic analysis. Among proteins whose expression was found to be significantly dysregulated following exposure of HMEC-1 to urea, dimethylarginine dimethylaminohydrolase (DDAH) and vasorin turned out to be down-regulated. Both proteins have been directly linked to cardiovascular diseases (CVD) by in vitro and in vivo studies. Future experiments will be needed to deepen their role and investigate the signaling pathways in which they are involved to clarify the possible link between CKD and CVD.

PDCD5 inhibits progression of renal cell carcinoma by promoting T cell immunity: with the involvement of the HDAC3/microRNA-195-5p/SGK1

BACKGROUND

Epigenetics exerts a vital role in the onset and development of renal cell carcinoma (RCC). Mounting evidence has shed light on the significance of human immune system in response to tumor infiltrating T cells. Hereby, we sought to unmask the immunomodulatory role of histone deacetylase 3 (HDAC3) and its potential upstream molecule, programmed cell death 5 (PDCD5) in RCC.

METHODS

RCC and adjacent non-cancerous tissues were clinically resected from 58 patients, in which the expression profile of microRNA-195-5p (miR-195-5p), PDCD5, HDAC3, and serum glucocorticoid-inducible kinase 1 (SGK1) was determined by RT-qPCR and Western blot analysis. Their relations were investigated by a series of luciferase assays in combination with ChIP and co-IP. RCC cells (A498) were intervened using gain- and loss-of-function approaches, followed by cell proliferation evaluation. After co-culture with CD3⁺ T cells, flow cytometry and interferon-γ (IFN-γ) determination were performed. A xenograft tumor mouse model was developed for in vivo validation.

RESULTS

PDCD5 was downregulated in RCC tissues and A498 cells. Upregulation of HDAC3, as well as of SGK1, resulted in suppression of A498 cell proliferation and promotion of T cell activation as evidenced by higher IFN-γ expression. Re-expression of PDCD5 downregulated HDAC3, causing a subsequent upregulation of miR-195-5p, while miR-195-5p could inversely modulate its target gene, SGK1. The regulatory mechanism appeared to be functional in vivo.

CONCLUSION

Our results highlight the possible manipulation by PDCD5 on RCC cell proliferation and T cell activation, which provides new clues to better understand the immune balance in RCC progression.

Suboptimal folic acid exposure rewires oncogenic metabolism and proteomics signatures to mediate human breast cancer malignancy

Whether treatment with folic acid (FA) affects human breast cancer positively or negatively remains unclear. We subjected human MCF-7 cells, a human breast cancer cell line, to suboptimal FA at low levels (10 nM; LF) and high levels (50 μM; HF) and investigated the molecular mechanisms underlying their effects through metabolic flux and systematic proteomics analyses. The data indicated that LF induced and HF aggravated 2-fold higher mitochondrial toxicity in terms of suppressed oxidative respiration, increased fermented glycolysis, and enhanced anchorage-independent oncospheroid formation. Quantitative proteomics and Gene Ontology enrichment analysis were used to profile LF- and HF-altered proteins involved in metabolism, apoptosis, and malignancy pathways. Through STRING analysis, we identified a connection network between LF- and HF-altered proteins with mTOR. Rapamycin-induced blockage of mTOR complex 1 (mTORC1) signaling, which regulates metabolism, differentially inhibited LF- and HF-modulated protein signatures of mitochondrial NADH dehydrogenase ubiquinone flavoprotein 2, mitochondrial glutathione peroxidase 4, kynureninase, and alpha-crystallin B chain as well as programmed cell death 5 in transcript levels; it subsequently diminished apoptosis and oncospheroid formation in LF/HF-exposed cells. Taken together, our data indicate that suboptimal FA treatment rewired oncogenic metabolism and mTORC1-mediated proteomics signatures to promote breast cancer development.

Type 2 Inflammation in Eosinophilic Esophagitis: From Pathophysiology to Therapeutic Targets

Eosinophilic esophagitis (EoE) is a chronic immune-mediated disease of the esophagus characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation, whose incidence is rising. It significantly affects patients’ quality of life and, if left untreated, results in fibrotic complications. Although broad consensus has been achieved on first-line therapy, a subset of patients remains non-responder to standard therapy. The pathogenesis of EoE is multifactorial and results from the complex, still mostly undefined, interaction between genetics and intrinsic factors, environment, and antigenic stimuli. A deep understanding of the pathophysiology of this disease is pivotal for the development of new therapies. This review provides a comprehensive description of the pathophysiology of EoE, starting from major pathogenic mechanisms (genetics, type 2 inflammation, epithelial barrier dysfunction, gastroesophageal reflux, allergens, infections and microbiota) and subsequently focusing on the single protagonists of type 2 inflammation (involved cells, cytokines, soluble effectors, surface proteins and transcription factors) that could represent present and future therapeutic targets, while summarizing previous therapeutic approaches in literature.

Programmed cell death 5 improves skeletal muscle insulin resistance by inhibiting IRS-1 ubiquitination through stabilization of MDM2

AIMS

Insulin resistance is defined as the decreased sensitivity of tissues and organs to insulin and it is the main pathological basis of metabolic syndrome. PDCD5 is widely expressed in tissues including skeletal muscle and liver, but its exact function and the role in insulin resistance has not been studied. The present study is to explore the effect of PDCD5 on insulin resistance in skeletal muscle, the largest target organ of insulin, and its mechanism.

MATERIALS AND METHODS

Mice were fed with high-fat diet to establish obesity model. C2C12 myoblasts differentiated into myotubes and then were treated with palmitate to induce insulin resistance. Gain-of-function and loss-of-function experiments were performed by infecting C2C12 with adenovirus containing PDCD5 cDNA or PDCD5 shRNA.

KEY FINDINGS

PDCD5 protein was first increased and then decreased in the skeletal muscle from high-fat diet induced obese mice and consistently in palmitate induced insulin resistance C2C12 myotubes. Overexpression of PDCD5 in C2C12 cells did not affect the sensitivity to insulin but inhibited the palmitate induced insulin resistance, while knockdown of PDCD5 aggravated the insulin resistance. Mechanistically, PDCD5 interacted with ubiquitin ligase MDM2; overexpression of PDCD5 decreased MDM2 protein level, inhibited the increased interaction of MDM2 with IRS-1 and the degradation of IRS-1 by palmitate stimulation.

SIGNIFICANCE

PDCD5 is upregulated during the early stage of insulin resistance in skeletal muscle. The increased PDCD5 inhibits IRS-1 ubiquitination, increases the stability of IRS-1 by interacting with and degrading MDM2, thus providing a protective effect on insulin resistance in skeletal muscle.

A proteomic-informed view of the changes induced by loss of cellular adherence: The example of mouse macrophages

Except cells circulating in the bloodstream, most cells in vertebrates are adherent. Studying the repercussions of adherence per se in cell physiology is thus very difficult to carry out, although it plays an important role in cancer biology, e.g. in the metastasis process. In order to study how adherence impacts major cell functions, we used a murine macrophage cell line. Opposite to the monocyte/macrophage system, where adherence is associated with the acquisition of differentiated functions, these cells can be grown in both adherent or suspension conditions without altering their differentiated functions (phagocytosis and inflammation signaling). We used a proteomic approach to cover a large panel of proteins potentially modified by the adherence status. Targeted experiments were carried out to validate the proteomic results, e.g. on metabolic enzymes, mitochondrial and cytoskeletal proteins. The mitochondrial activity was increased in non-adherent cells compared with adherent cells, without differences in glucose consumption. Concerning the cytoskeleton, a rearrangement of the actin organization (filopodia vs sub-cortical network) and of the microtubule network were observed between adherent and non-adherent cells. Taken together, these data show the mechanisms at play for the modification of the cytoskeleton and also modifications of the metabolic activity between adherent and non-adherent cells.

Club cell-specific role of programmed cell death 5 in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) causes progressive fibrosis and worsening pulmonary function. Prognosis is poor and no effective therapies exist. We show that programmed cell death 5 (PDCD5) expression is increased in the lungs of patients with IPF and in mouse models of lung fibrosis. Lung fibrosis is significantly diminished by club cell-specific deletion of Pdcd5 gene. PDCD5 mediates β-catenin/Smad3 complex formation, promoting TGF-β-induced transcriptional activation of matricellular genes. Club cell Pdcd5 knockdown reduces matricellular protein secretion, inhibiting fibroblast proliferation and collagen synthesis. Here, we demonstrate the club cell-specific role of PDCD5 as a mediator of lung fibrosis and potential therapeutic target for IPF.

Idiopathic pulmonary fibrosis (IPF) is a fatal adult lung disease. Here the authors investigate the functional significance of PDCD5 in club cells as a mediator of lung fibrosis and potential therapeutic target for IPF.

In-vitro and in-vivo evaluation of the molecular mechanisms involved in the toxicity associated to CdSe/ZnS quantum dots exposure

The use of different types of quantum dots is growing in recent times in both the technology and biomedical industries. Such is the extension of the use of these quantum dots that they have become potential emerging contaminants, which makes it necessary to evaluate their potential toxicity and the impact they may have on both health and the environment. Although studies already exist in this regard, the molecular mechanisms by which CdSe/ZnS quantum dots exert their toxic effects are still unknown. For this reason, in this study, a comprehensive proteomic approach has been designed, applying the SILAC strategy to an in-vitro model (hepatic cells) and the super-SILAC alternative to an in-vivo model, specifically zebrafish larvae. This integral approach, together with additional bioanalytical assays, has made it possible for the identification of proteins, molecular mechanisms and, therefore, biological processes that are altered as a consequence of exposure to CdSe/ZnS quantum dots. It has been demonstrated, on the one hand, that these quantum dots induce hypoxia and ROS generation in hepatic cells, which leads to apoptosis, specifically through the TDP-43 pathway. On the other hand, it has been shown that exposure to CdSe/ZnS quantum dots has a high impact on developing organisms, inducing serious neural and developmental problems in the locomotor system.

Development on Citrus medica infected with 'Candidatus Liberibacter asiaticus' has sex-specific and -nonspecific impacts on adult Diaphorina citri and its endosymbionts

Huanglongbing (HLB) is a deadly, incurable citrus disease putatively caused by the unculturable bacterium, 'Candidatus Liberibacter asiaticus' (CLas), and transmitted by Diaphorina citri. Prior studies suggest D. citri transmits CLas in a circulative and propagative manner; however, the precise interactions necessary for CLas transmission remain unknown, and the impact of insect sex on D. citri-CLas interactions is poorly understood despite reports of sex-dependent susceptibilities to CLas. We analyzed the transcriptome, proteome, metabolome, and microbiome of male and female adult D. citri reared on healthy or CLas-infected Citrus medica to determine shared and sex-specific responses of D. citri and its endosymbionts to CLas exposure. More sex-specific than shared D. citri responses to CLas were observed, despite there being no difference between males and females in CLas density or relative abundance. CLas exposure altered the abundance of proteins involved in immunity and cellular and oxidative stress in a sex-dependent manner. CLas exposure impacted cuticular proteins and enzymes involved in chitin degradation, as well as energy metabolism and abundance of the endosymbiont 'Candidatus Profftella armatura' in both sexes similarly. Notably, diaphorin, a toxic Profftella-derived metabolite, was more abundant in both sexes with CLas exposure. The responses reported here resulted from a combination of CLas colonization of D. citri as well as the effect of CLas infection on C. medica. Elucidating these impacts on D. citri and their endosymbionts contributes to our understanding of the HLB pathosystem and identifies the responses potentially critical to limiting or promoting CLas acquisition and propagation in both sexes.

Pathogenesis of Eosinophilic Esophagitis: A Comprehensive Review of the Genetic and Molecular Aspects

Eosinophilic esophagitis (EoE) is a relatively new condition described as an allergic-mediated disease of the esophagus. Clinically, it is characterized by dysphagia, food impaction, and reflux-like symptoms. Multiple genome-wide association studies (GWAS) have been conducted to identify genetic loci associated with EoE. The integration of numerous studies investigating the genetic polymorphisms in EoE and the Mendelian diseases associated with EoE are discussed to provide insights into the genetic risk of EoE, notably focusing on CCL26 and CAPN14. We focus on the genetic loci investigated thus far, and their classification according to whether the function near the loci is known. The pathophysiology of EoE is described by separately presenting the known function of each cell and molecule, with the major contributors being eosinophils, Th2 cells, thymic stromal lymphopoietin (TSLP), transforming growth factor (TGF)-β1, and interleukin (IL)-13. This review aims to provide detailed descriptions of the genetics and the comprehensive pathophysiology of EoE.

The Global Phosphorylation Landscape of SARS-CoV-2 Infection

The causative agent of the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected millions and killed hundreds of thousands of people worldwide, highlighting an urgent need to develop antiviral therapies. Here we present a quantitative mass spectrometry-based phosphoproteomics survey of SARS-CoV-2 infection in Vero E6 cells, revealing dramatic rewiring of phosphorylation on host and viral proteins. SARS-CoV-2 infection promoted casein kinase II (CK2) and p38 MAPK activation, production of diverse cytokines, and shutdown of mitotic kinases, resulting in cell cycle arrest. Infection also stimulated a marked induction of CK2-containing filopodial protrusions possessing budding viral particles. Eighty-seven drugs and compounds were identified by mapping global phosphorylation profiles to dysregulated kinases and pathways. We found pharmacologic inhibition of the p38, CK2, CDK, AXL, and PIKFYVE kinases to possess antiviral efficacy, representing potential COVID-19 therapies.

Effects of Yersinia ruckeri invasion on the proteome of the Chinook salmon cell line CHSE-214

Yersinia ruckeri is an important bacterial pathogen of fish, in particular salmonids, it has been associated with systemic infections worldwide and, like many enteric bacteria, it is a facultative intracellular pathogen. However, the effect of Y. ruckeri's interactions with the host at the cellular level have received little investigation. In the present study, a culture of Chinook Salmon Embryo (CHSE) cell line was exposed to Y. ruckeri. Afterwards, the proteins were investigated and identified by mass spectrometry and compared to the content of unexposed cultures. The results of this comparison showed that 4.7% of the identified proteins were found at significantly altered concentrations following infection. Interestingly, infection with Y. ruckeri was associated with significant changes in the concentration of surface adhesion proteins, including a significantly decreased presence of β-integrins. These surface adhesion molecules are known to be the target for several adhesion molecules of Yersiniaceae. The concentration of several anti-apoptotic regulators (HSP90 and two DNAj molecules) appeared similarly downregulated. Taken together, these findings suggest that Y. ruckeri affects the proteome of infected cells in a notable manner and our results shed some light on the interaction between this important bacterial pathogen and its host.

CIGB-300 anticancer peptide regulates the protein kinase CK2-dependent phosphoproteome

Casein-kinase CK2 is a Ser/Thr protein kinase that fosters cell survival and proliferation of malignant cells. The CK2 holoenzyme, formed by the association of two catalytic alpha/alpha' (CK2α/CK2α') and two regulatory beta subunits (CK2β), phosphorylates diverse intracellular proteins partaking in key cellular processes. A handful of such CK2 substrates have been identified as targets for the substrate-binding anticancer peptide CIGB-300. However, since CK2β also contains a CK2 phosphorylation consensus motif, this peptide may also directly impinge on CK2 enzymatic activity, thus globally modifying the CK2-dependent phosphoproteome. To address such a possibility, firstly, we evaluated the potential interaction of CIGB-300 with CK2 subunits, both in cell-free assays and cellular lysates, as well as its effect on CK2 enzymatic activity. Then, we performed a phosphoproteomic survey focusing on early inhibitory events triggered by CIGB-300 and identified those CK2 substrates significantly inhibited along with disturbed cellular processes. Altogether, we provided here the first evidence for a direct impairment of CK2 enzymatic activity by CIGB-300. Of note, both CK2-mediated inhibitory mechanisms of this anticancer peptide (i.e., substrate- and enzyme-binding mechanism) may run in parallel in tumor cells and help to explain the different anti-neoplastic effects exerted by CIGB-300 in preclinical cancer models.

Clinicopathological Significance of Decreased Expression of the Tumor Inhibitor Gene PDCD5 in Osteoclastoma

Background: The gene programmed cell death 5 (PDCD5) has recently been characterized as a tumor suppressor gene and is believed to be an important prognostic cancer marker; it is frequently involved in neoplastic transformation and apoptosis of tumor cells. Several studies have demonstrated a decrease or loss of expression of PDCD5 in certain tumors. However, the relevance of PDCD5 expression in human osteoclastoma and its clinicopathological significance have not been extensively studied. Methods: The aim of this study was to explore the relative transcriptional and translational expression levels of PDCD5 in 79 osteoclastoma samples using multi-modal methods of analysis. Results: Our findings showed that 52% (15/29) of osteoclastoma cases exhibited reduced PDCD5 expression at the transcriptional level, and 56% (44/79) exhibited lower PDCD5 expression at the protein level, when compared with nontumor tissue. In addition, the statistical significance of the altered PDCD5 protein expression was examined using the Campanacci grading system for osteoclastoma. More importantly, the decreased expression at the translational level was observed to have a negative association with the Ki-67 staining index. Conclusion: Based on these findings, abnormal PDCD5 expression might be an important biomarker in human osteoclastoma and may contribute to tumor progression and malignant cell proliferation.

The Molecular Evolution and Functional Divergence of Lamprey Programmed Cell Death Genes

The programmed cell death (PDCD) family plays a significant role in the regulation of cell survival and apoptotic cell death. However, the evolution, distribution and role of the PDCD family in lampreys have not been revealed. Thus, we identified the PDCD gene family in the lamprey genome and classified the genes into five subfamilies based on orthologs of the genes, conserved synteny, functional domains, phylogenetic tree, and conserved motifs. The distribution of the lamprey PDCD family and the immune response of the PDCD family in lampreys stimulated by different pathogens were also demonstrated. In addition, we investigated the molecular function of lamprey PDCD2, PDCD5, and PDCD10. Our studies showed that the recombinant lamprey PDCD5 protein and transfection of the L-PDCD5 gene induced cell apoptosis, upregulated the expression of the associated X protein (BAX) and TP53 and downregulated the expression of B cell lymphoma 2 (BCL-2) independent of Caspase 3. In contrast, lamprey PDCD10 suppressed apoptosis in response to cis-diaminedichloro-platinum (II) stimuli. Our phylogenetic and functional data not only provide a better understanding of the evolution of lamprey PDCD genes but also reveal the conservation of PDCD genes in apoptosis. Overall, our results provide a novel perspective on lamprey immune regulation mediated by the PDCD family.

Lgr5-mediated p53 Repression through PDCD5 leads to doxorubicin resistance in Hepatocellular Carcinoma

The devastating prognosis of hepatocellular carcinoma (HCC) is partially attributed to chemotherapy resistance. Accumulating evidence suggests that the epithelial-mesenchymal transition (EMT) is a key driving force of carcinoma metastasis and chemoresistance in solid tumors. Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5), as an EMT inducer, is involved in the potentiation of Wnt signaling in HCC. This study proposes uncovering the roles of Lgr5 in Doxorubicin (Dox) resistance of HCC to improve treatment efficacy for HCC.

Methods: We investigated the expression and significance of Lgr5 in HCC tissue and different cell lines. The effect of Lgr5 in EMT and Dox resistance was analyzed in HCC cells and implanted HCC tumor models. A two-hybrid analysis, using the Lgr5 gene as the bait and a HCC cDNA library, was used to screen targeted proteins that interact with Lgr5. The positive clones were identified by coimmunoprecipitation (Co-IP) and Glutathione-S-transferase (GST) pull-down. The impact of the interaction on Dox resistance was investigated by a series of assays in vitro and in vivo .

Result: We found that Lgr5 was upregulated and positively correlated with poor prognosis in HCC. Additionally, it functioned as a tumor promoter to increase cell migration and induce EMT in HCC cells and increase the resistance to Dox. We identified programmed cell death protein 5 (PDCD5) as a target gene of Lgr5 and we found that PDCD5 was responsible for Lgr5-mediated Dox resistance. Further analysis with Co-IP and GST pull-down assays showed that the N-terminal extracellular domain of Lgr5 could directly bind to PDCD5. Lgr5 induced p53 degradation by blocking the nuclear translocation of PDCD5 and leading to the loss of p53 stabilization. Lgr5 showed a protection against the inhibition of Dox on the growth of tumor subcutaneously injected. Moreover, Lgr5 suppressed Dox-induced apoptosis via the p53 pathway and attenuated the cytotoxicity of Dox to HCC.

Conclusion: Lgr5 induces the EMT and inhibits apoptosis, thus promoting chemoresistance by regulating the PDCD5/p53 signaling axis. Furthermore, Lgr5 may be a potential target gene for overcoming Dox resistance.

In-depth proteomic characterization of Schistosoma haematobium: Towards the development of new tools for elimination

BACKGROUND

Schistosomiasis is a neglected disease affecting hundreds of millions worldwide. Of the three main species affecting humans, Schistosoma haematobium is the most common, and is the leading cause of urogenital schistosomiasis. S. haematobium infection can cause different urogenital clinical complications, particularly in the bladder, and furthermore, this parasite has been strongly linked with squamous cell carcinoma. A comprehensive analysis of the molecular composition of its different proteomes will contribute to developing new tools against this devastating disease.

METHODS AND FINDINGS

By combining a comprehensive protein fractionation approach consisting of OFFGEL electrophoresis with high-throughput mass spectrometry, we have performed the first in-depth characterisation of the different discrete proteomes of S. haematobium that are predicted to interact with human host tissues, including the secreted and tegumental proteomes of adult flukes and secreted and soluble egg proteomes. A total of 662, 239, 210 and 138 proteins were found in the adult tegument, adult secreted, soluble egg and secreted egg proteomes, respectively. In addition, we probed these distinct proteomes with urine to assess urinary antibody responses from naturally infected human subjects with different infection intensities, and identified adult fluke secreted and tegument extracts as being the best predictors of infection.

CONCLUSION

We provide a comprehensive dataset of proteins from the adult and egg stages of S. haematobium and highlight their utility as diagnostic markers of infection intensity. Protein composition was markedly different between the different extracts, highlighting the distinct subsets of proteins that different development stages present in their different niches. Furthermore, we have identified adult fluke ES and tegument extracts as best predictors of infection using urine antibodies of naturally infected people. This study provides the first steps towards the development of novel tools to control this important neglected tropical disease.

Programmed Cell Death 5 Provides Negative Feedback on Cardiac Hypertrophy Through the Stabilization of Sarco/Endoplasmic Reticulum Ca2+-ATPase 2a Protein

PDCD5 (programmed cell death 5) is ubiquitously expressed in tissues, including the heart; however, the mechanism underlying the cardiac function of PDCD5 has not been understood. We investigated the mechanisms of PDCD5 in the pathogenesis of cardiac hypertrophy. Cardiac-specific PDCD5 knockout mice developed severe cardiac hypertrophy and impaired cardiac function, whereas PDCD5 protein was significantly increased in transverse aortic constriction mouse hearts and phenylephrine-stimulated cardiomyocytes. Overexpression of PDCD5 inhibited phenylephrine-induced cardiomyocyte hypertrophy, and knockdown of PDCD5 induced cardiomyocyte hypertrophy and aggravated phenylephrine-induced hypertrophy. The expression of PDCD5 protein was regulated by NFATc2 (nuclear factor of activated T cells c2) during hypertrophy. SERCA2a (sarco/endoplasmic reticulum Ca²⁺-ATPase 2a) expression was decreased in PDCD5-deficient mouse hearts because of increased ubiquitination. PDCD5-deficient cardiomyocytes displayed decreased calcium uptake rate, slowed decay of Ca²⁺ transients, decreased calcium stores, and diastolic dysfunction. Moreover, reintroduction of PDCD5 in PDCD5-deficient mouse hearts reserved SERCA2a protein, suppressed NFATc2 protein, and rescued the hypertrophy and cardiac dysfunction. Our results revealed that PDCD5 is a novel target of NFATc2 in the hypertrophic heart and provides negative feedback to protect the heart against excessive hypertrophy via the stabilization of SERCA2a protein.

Crystal structure of the programmed cell death 5 protein from Sulfolobus solfataricus

Programmed cell death 5 (PDCD5) is a vital signaling protein in the apoptosis pathway in eukaryotes. It is known that there are two dissociated N-terminal regions and a triple-helix core in eukaryotic PDCD5. Structural and functional studies of PDCD5 from hyperthermophilic archaea have been limited to date. Here, the PDCD5 homolog Sso0352 (SsoPDCD5) was identified in Sulfolobus solfataricus, the SsoPDCD5 protein was expressed and crystallized, and the phase was identified by single-wavelength anomalous diffraction. The native SsoPDCD5 crystal belonged to space group C2 and diffracted to 1.49 Å resolution. This is the first crystal structure of a PDCD5 homolog to be solved. SsoPDCD5 shares a similar triple-helix bundle with eukaryotic PDCD5 but has a long α-helix in the N-terminus. A structural search and biochemical data suggest that SsoPDCD5 may function as a DNA-binding protein.

miR-134 targets PDCD7 to reduce E-cadherin expression and enhance oral cancer progression

Oral squamous cell carcinoma (OSCC) is a common malignancy worldwide. This study clarified the oncogenic role of miR-134 in OSCC. Reporter assays, using both wild-type and mutant constructs, confirmed that Programmed Cell Death 7 (PDCD7) gene was a potential target of miR-134. The OSCC cells exogenously expressed miR-134 exhibited reduced PDCD7 expression. As expected, exogenous miRZip-134 expression increased PDCD7 expression in the OSCC cells; additionally, PDCD7 expression suppressed the oncogenicity of the OSCC cells. By contrast, PDCD7 knockout through gene editing increased in vitro oncogenicity and neck nodal metastasis in mice, and reduced E-cadherin (E-cad) expression. PDCD7 transactivated E-cad expression via the GC-box in the promoter. Moreover, miR-134-associated cellular transformation and E-cad downregulation was attenuated by PDCD7. Downregulation of both PDCD7 and E-cad and high levels miR-134 expression was observed in OSCC tumor tissues. Activation of the miR-134-PDCD7-E-cad pathogenesis cascade occurred early during the human and murine oral carcinogenesis process. In conclusion, the oncogenic effect of miR-134 in oral carcinoma is mediated by reducing PDCD7 and E-cad expression.

PDCD5 regulates iNKT cell terminal maturation and iNKT1 fate decision

Invariant natural killer T1 (iNKT1) cells are characterized by the preferential expression of T-box transcription factor T-bet (encoded by Tbx21) and the production of cytokine IFN-γ, but the relationship between the developmental process and iNKT1 lineage diversification in the thymus remains elusive. We report in the present study a crucial role of programmed cell death 5 (PDCD5) in iNKT cell terminal maturation and iNKT1 fate determination. Mice with T cell-specific deletion of PDCD5 had decreased numbers of thymic and peripheral iNKT cells with a predominantly immature phenotype and defects in response to α-galactosylceramide. Loss of PDCD5 also selectively abolished the iNKT1 lineage by reducing T-bet expression in iNKT cells at an early thymic developmental stage (before CD44 upregulation). We further demonstrated that TOX2, one of the high mobility group proteins that was highly expressed in iNKT cells at stage 1 and could be stabilized by PDCD5, promoted the permissive histone H3K4me3 modification in the promoter region of Tbx21. These data indicate a pivotal and unique role of PDCD5/TOX2 in iNKT1 lineage determination. They also suggest that the fate of iNKT1 may be programmed at the developmental stage of iNKT cells in the thymus.

The Expression of TMEM74 in Liver Cancer and Lung Cancer Correlating With Survival Outcomes

Transmembrane 74 (TMEM74), a transmembrane protein as an autophagy inducer, has been proven to promote tumor cell (including cervical cancer cell line HeLa and hepatic carcinoma cell line HepG2) proliferation by triggering autophagy. To further determine the role of TMEM74 in cancer, we performed immunohistochemical staining on tissue array, and the results showed that TMEM74 exhibited significantly higher expression in several tumor types, especially in hepatocellular carcinoma, lung adenocarcinoma, and squamous carcinoma. Furthermore, higher expression level of TMEM74 in HepG2, A549, and H1299 cell lines were also detected compared with the corresponding normal cell lines, as detected by western blot. Meanwhile, further analysis showed that the levels of TMEM74 expression were closely correlated to survival period of patients-the higher expression of TMEM74 was correlated with shorter survival period. Moreover, the in vitro experiments showed that overexpression of TMEM74 led to accelerated proliferation of A549 and H1299 cells, while knockdown of TMEM74 reversed the outcomes. In conclusion, the results suggested that TMEM74 acts as an oncogene and a potential diagnostic marker and a therapeutic target for liver cancer and lung cancer.

Programmed cell death 5 transgenic mice attenuates adjuvant induced arthritis by 2 modifying the T lymphocytes balance

BACKGROUND

Programmed cell death 5 (PDCD5) is an apoptosis-related gene cloned from TF-1 cells whose primary biological functions are to promote apoptosis and immune regulation. The effects and mechanisms exerted by key mediators of arthritic inflammation remain unclear in PDCD5 transgenic (PDCD5 tg) mice.

RESULTS

In the current study, PDCD5 tg mice inhibited the progression of adjuvant-induced arthritis, specifically decreasing clinical signs and histological damage, compared with arthritis control mice. Additionally, the ratio of CD4⁺IFN-γ⁺ cells (Th1) and CD4⁺IL-17A⁺ cells (Th17), as well as the mRNA expression of the pro-inflammatory mediators IFN-γ, IL-6, IL-17A and TNF-α, were decreased in PDCD5 tg mice, while CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells and the anti-inflammatory mediators IL-4 and IL-10 were increased. Furthermore, PDCD5 tg mice demonstrated reduced serum levels of IFN-γ, IL-6, IL-17A and TNF-α and increased levels of IL-4.

CONCLUSIONS

Based on our data, PDCD5 exerts anti-inflammatory effects by modifying the T lymphocytes balance, inhibiting the production of pro-inflammatory mediators and promoting the secretion of anti-inflammatory cytokines, validating PDCD5 protein as a possible treatment for RA.

PDCD5 regulates cell proliferation, cell cycle progression and apoptosis

Programmed cell death (PDCD)5 is cloned from human leukemia cell line TF-1. PDCD5 is one of the members of the programmed cell death protein family that is frequently involved in tumor growth and apoptosis. To investigate the molecular and cellular functions of PDCD5, the present study established a PDCD5 stably overexpressing A431 cell line and examined the role of PDCD5 in cell proliferation, cell cycle progression and apoptosis. The data demonstrated that overexpression of PDCD5 significantly inhibited cell proliferation, induced cell cycle arrest at G2/M phase and apoptosis in A431 cells. The expression profiles of certain key regulators of these cellular events were further investigated, including P53, B cell lymphoma (BCL)-2, BCL-2 associated X protein (BAX) and caspase (CASP)3. The data demonstrated that at the transcript and protein levels, P53, BAX and CASP3 were all upregulated in the PDCD5 stably overexpressing A431 cells whereas BCL-2 was downregulated, indicating that PDCD5 acts as an important upstream regulator of P53, BCL-2, BAX and CASP3. The data suggest that PDCD5 regulates cell proliferation, cell cycle progression and apoptosis in A431 cells. PDCD5 may be a novel tumor suppressor gene, and may be potentially used for cancer treatment in the future.

ZBTB7A Enhances Osteosarcoma Chemoresistance by Transcriptionally Repressing lncRNALINC00473-IL24 Activity

Chemoresistance remains a major drawback to osteosarcoma treatment. ZBTB7A, a member of the POK transcription repressor family, was shown to play an important role in tumorigenesis. However, the effect of ZBTB7A on osteosarcoma chemoresistance is completely unknown. In this study, we found that ZBTB7A is increased in cisplatin-resistant osteosarcoma cells and that elevated ZBTB7A inhibits cisplatin-induced apoptosis by repressing LINC00473 expression. Further mechanistic studies revealed that ZBTB7A directly binds to the promoter and suppresses the transcription of LINC00473. Additionally, our data indicate that LINC00473 interacts with the transcript factor C/EBPβ, facilitating its binding to the promoter of IL24, leading to decrease chemoresistance. Thus, these findings indicate that the ZBTB7A-mediated LINC00473-C/EBPβ-IL24 pathway is a promising novel target for overcoming cisplatin resistance in osteosarcoma.

Deletion of Pdcd5 in mice led to the deficiency of placenta development and embryonic lethality

Programmed cell death 5 (PDCD5) is an apoptosis promoter molecule that displays multiple biological activities. However, the function of PDCD5 in vivo has not yet been investigated. Here, we generated a Pdcd5 knockout mouse model to study the physiological role of PDCD5 in vivo. Knockout of the Pdcd5 gene resulted in embryonic lethality at mid-gestation. Histopathological analysis revealed dysplasia in both the LZs and JZs in Pdcd5^–/– placentas with defects in spongiotrophoblasts and trophoblast giant cells. Furthermore, Pdcd5^–/– embryos had impaired transplacental passage capacity. We also found that Pdcd5^–/– embryos exhibited cardiac abnormalities and defective liver development. The growth defect is linked to impaired placental development and may be caused by insufficient oxygen and nutrient transfer across the placenta. These findings were verified in vitro in Pdcd5 knockout mouse embryonic fibroblasts, which showed increased apoptosis and G0/G1 phase cell cycle arrest. Pdcd5 knockout decreased the Vegf and hepatocyte growth factor (Hgf) levels, downregulated the downstream Pik3ca–Akt–Mtor signal pathway and decreased cell survival. Collectively, our studies demonstrated that Pdcd5 knockout in mouse embryos results in placental defects and embryonic lethality.

Genetics of eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic, allergic disease associated with marked mucosal eosinophil accumulation. EoE disease risk is multifactorial and includes environmental and genetic factors. This review will focus on the contribution of genetic variation to EoE risk, as well as the experimental tools and statistical methodology used to identify EoE risk loci. Specific disease-risk loci that are shared between EoE and other allergic diseases (TSLP, LRRC32) or unique to EoE (CAPN14), as well as Mendellian Disorders associated with EoE, will be reviewed in the context of the insight that they provide into the molecular pathoetiology of EoE. We will also discuss the clinical opportunities that genetic analyses provide in the form of decision support tools, molecular diagnostics, and novel therapeutic approaches.

The reduced PDCD5 protein is correlated with the degree of tumor differentiation in endometrioid endometrial carcinoma

Endometrial cancer is one of the most common malignancies in the female genital tract. Programmed cell death 5 (PDCD5) is a newly identified apoptosis related gene and plays an important role in the development of some human tumors. However, the expression and clinical significance of PDCD5 in endometrial cancer have not been fully elucidated. Here, we evaluated the expression of PDCD5 in endometrioid endometrial carcinoma and control endometrium by qRT-PCR, western blot and immunohistochemistry, and analyzed the associations of PDCD5 expression with clinicopathological parameters of patients. In addition, we detected the expression of PDCD5 in control endometrial glandular epithelial cells and endometrioid endometrial carcinoma-derived cell line KLE by immunocytochemistry. The results showed that PDCD5 protein mainly expressed in the cytoplasm of glandular epithelial cells and endometrial carcinoma cells, and there was a low level of PDCD5 expression in the nuclei of the above cells. Furthermore, PDCD5 protein level was significantly lower in endometrial carcinoma samples than that in control endometrium. The decreased PDCD5 expression was correlated with the tumor differentiation degree. It is clear that PDCD5 protein expression was lower in middle and low differentiated endometrial carcinoma compared with control endometrium and high differentiated endometrial carcinoma. However, there were no significant differences of PDCD5 expression between the proliferative phase and the secretory phase of control endometrium, as well as between high differentiated endometrial carcinoma and controls. The results were verified in control glandular epithelial cells and KLE cells by immunocytochemistry. Therefore, PDCD5 may play a key role in the pathogenesis of endometrial cancer and may be a novel target for diagnosis and treatment of endometrial cancer.