Expression of pre-selected TMEMs with predicted ER localization as potential classifiers of ccRCC tumors

The roles and functions of TMEM protein family members in cancers, cardiovascular and kidney diseases (Review)

Transmembrane protein (TMEM) is a type of membrane proteins, encoded by TMEM gene, also known as integral membrane protein. TMEM gene family contains various members and its encoded proteins have various functions and expressed in numerous organs. It has been proved to be widely involved in the formation of a lot of organelle membranes, enzymes, receptors and channels, mediating numerous normal physiological functions and regulating various disease processes. At present, accumulating evidences at home and abroad have shown that TMEM is involved in regulating the occurrence and development of different tumors, cardiovascular and kidney diseases. The improved understanding of molecular mechanisms of TMEM genes and proteins may provide new directions and ideas for the prevention, diagnosis and treatment of diseases. In the present review, the roles of TMEM and biological functions in various cancers, cardiovascular and kidney diseases were discussed.

Deciphering the role of TMEM164 in autophagy-mediated ferroptosis and immune modulation in non-small cell lung cancer

BACKGROUND

Non-small cell lung cancer (NSCLC) remains one of the most prevalent and deadly malignancies. Despite advancements in molecular therapies and diagnostic methods, the 5-year survival rate for lung adenocarcinoma patients remains unacceptably low, highlighting the urgent need for novel therapeutic strategies. Ferroptosis, a distinct form of regulated cell death, has emerged as a promising target in cancer treatment. This study investigates the role of TMEM164, a membrane protein, in promoting ferroptosis and modulating anti-tumor immunity in NSCLC, aiming to elucidate its therapeutic potential.

METHODS

Using publicly available datasets, we performed bioinformatics analyses to identify TMEM164-regulated genes involved in ferroptosis. In addition, in vitro and in vivo assays were conducted to assess the impact of TMEM164 on cellular functions in NSCLC.

RESULTS

Functional assays demonstrated that TMEM164 overexpression significantly inhibited invasion, migration, and cell proliferation in both in vitro and in vivo models. TMEM164 was also found to induce ferroptosis in NSCLC cells by promoting autophagy. Specifically, we identified a mechanism whereby TMEM164 mediates ATG5-dependent autophagosome formation, leading to the degradation of ferritin, GPX4, and lipid droplets. This degradation facilitated iron accumulation and lipid peroxidation, which triggered iron-dependent cell death. Notably, co-administration of TMEM164 upregulation and anti-PD-1 antibodies exhibited synergistic anti-tumor effects in a mouse model.

CONCLUSION

These findings suggest that targeting TMEM164 to enhance ferroptosis and stimulate anti-tumor immunity may inhibit NSCLC progression. Consequently, TMEM164 holds promise as a new therapeutic target for NSCLC treatment.

The emerging role of transmembrane proteins in tumorigenesis and therapy

Transmembrane proteins (TMEMs) are a kind of proteins that can cross the phospholipid bilayer one or multiple times and remain permanently anchored. They are involved in the regulation of many biological functions, and their dysregulation is associated with many human diseases and even cancer. Abnormal expression alterations of TMEMs widely exist in tumor tissues compared with paracancerous tissues. They are associated with the clinicopathological features of cancer patients by promoting or inhibiting the development of cancer, thus affecting survival. This review summarized the structure and physiological functions of TMEMs, as well as their roles in tumorigenesis, such as cell proliferation, apoptosis, autophagy, adhesion, metastasis, metabolism and drug resistance. In addition, we elaborated on the potentiality of TMEMs for tumor immunity. Moreover, the advances of TMEMs were subsequently retrospected in several common types of human cancers, including breast cancer, gastric cancer, and lung cancer. Subsequently, we outlined the targeted therapeutic strategies against TMEMs proposed based on existing studies. To date, there are still many TMEMs whose functions and mechanisms have not been well known due to their special structures. Since the important roles TMEMs plays in the development of human cancers, it is urgent to portray their structure and function in carcinogenesis, providing potential biomarkers for cancer patients in the future.

CREB3L1 deficiency impairs odontoblastic differentiation and molar dentin deposition partially through the TMEM30B

Odontoblasts are primarily responsible for synthesizing and secreting extracellular matrix proteins, which are crucial for dentinogenesis. Our previous single-cell profile and RNAscope for odontoblast lineage revealed that cyclic adenosine monophosphate responsive element-binding protein 3 like 1 (Creb3l1) was specifically enriched in the terminal differentiated odontoblasts. In this study, deletion of Creb3l1 in the Wnt1+ lineage led to insufficient root elongation and dentin deposition. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing were performed to revealed that in CREB3L1-deficient mouse dental papilla cells (mDPCs), the genes near the closed chromatin regions were mainly associated with mesenchymal development and the downregulated genes were primarily related to biological processes including cell differentiation, protein biosynthesis and transport, all of which were evidenced by a diminished ability of odontoblastic differentiation, a significant reduction in intracellular proteins, and an even greater decline in extracellular supernatant proteins. Dentin matrix protein 1 (Dmp1), dentin sialophosphoprotein (Dspp), and transmembrane protein 30B (Tmem30b) were identified as direct transcriptional regulatory targets. TMEM30B was intensively expressed in the differentiated odontoblasts, and exhibited a significant decline in both CREB3L1-deficient odontoblasts in vivo and in vitro. Deletion of Tmem30b impaired the ability of odontoblastic differentiation, protein synthesis, and protein secretion in mDPCs. Moreover, overexpressing TMEM30B in CREB3L1-deficient mDPCs partially rescued the extracellular proteins secretion. Collectively, our findings suggest that CREB3L1 participates in dentinogenesis and facilitates odontoblastic differentiation by directly enhancing the transcription of Dmp1, Dspp, and other differentiation-related genes and indirectly promoting protein secretion partially via TMEM30B.

TRPM8 overexpression suppresses hepatocellular carcinoma progression and improves survival by modulating the RTP3/STAT3 pathway

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is a malignant tumour associated with high morbidity and mortality rates worldwide. Recently, TRPM8 was reported to play an important role in tumour progression. However, the precise role of TRPM8 in HCC remains unclear. In this study, we explored the expression levels, molecular functions and underlying mechanisms of TRPM8 in HCC.

METHODS

Tissue samples were used to analyse the expression of TRPM8 to assess its diagnostic value for prognosis. Cell Counting Kit-8, EdU and colony formation assays were performed to evaluate the effects of TRPM8 on cell proliferation, whereas the Transwell assay was used to assess cell migration and invasion. The role of TRPM8 in vivo was evaluated using a mouse subcutaneous xenograft tumour model. We performed PPI network analyses to understand the possible mechanisms of TRPM8 action.

RESULTS

TRPM8 expression was decreased in HCC tissues and was correlated with histological grade and poor patient prognosis. Functionally, TRPM8 repressed the proliferation and metastasis of HCC cells both in vitro and in vivo by modulating the RTP3/STAT3 signalling pathway.

CONCLUSION

Our findings underscore the critical role of the TRPM8-RTP3-STAT3 axis in maintaining the malignant progression of HCC. Moreover, our study demonstrates that AD80 is involved in anti-tumour processes by upregulating the expression of TRPM8.

Ovarian cancer ascites proteomic profile reflects metabolic changes during disease progression

Ovarian cancer (OC) patients develop ascites, an accumulation of ascitic fluid in the peritoneal cavity anda sign of tumour dissemination within the peritoneal cavity. This body fluid is under-researched, mainly regarding the ascites formed during tumour progression that have no diagnostic value and, therefore, are discarded. We performed a discovery proteomics study to identify new biomarkers in the ascites supernatant of OC patients. In this preliminary study, we analyzed a small amount of OC ascites to highlight the importance of not discarding such biological material during treatment, which could be valuable for OC management. Our findings reveal that OC malignant ascitic fluid (MAF) displays a proliferative environment that promotes the growth of OC cells that shift the metabolic pathway using alternative sources of nutrients, such as the cholesterol pathway. Also, OC ascites drained from patients during treatment showed an immunosuppressive environment, with up-regulation of proteins from the signaling pathways of IL-4 and IL-13 and down-regulation from the MHC-II. This preliminary study pinpointed a new protein (Transmembrane Protein 132A) in the OC context that deserves to be better explored in a more extensive cohort of patients' samples. The proteomic profile of MAF from OC patients provides a unique insight into the metabolic kinetics of cancer cells during disease progression, and this information can be used to develop more effective treatment strategies.

Thioredoxin Domain Containing 5 (TXNDC5): Friend or Foe?

This review focuses on the thioredoxin domain containing 5 (TXNDC5), also known as endoplasmic reticulum protein 46 (ERp46), a member of the protein disulfide isomerase (PDI) family with a dual role in multiple diseases. TXNDC5 is highly expressed in endothelial cells, fibroblasts, pancreatic β-cells, liver cells, and hypoxic tissues, such as cancer endothelial cells and atherosclerotic plaques. TXNDC5 plays a crucial role in regulating cell proliferation, apoptosis, migration, and antioxidative stress. Its potential significance in cancer warrants further investigation, given the altered and highly adaptable metabolism of tumor cells. It has been reported that both high and low levels of TXNDC5 expression are associated with multiple diseases, such as arthritis, cancer, diabetes, brain diseases, and infections, as well as worse prognoses. TXNDC5 has been attributed to both oncogenic and tumor-suppressive features. It has been concluded that in cancer, TXNDC5 acts as a foe and responds to metabolic and cellular stress signals to promote the survival of tumor cells against apoptosis. Conversely, in normal cells, TXNDC5 acts as a friend to safeguard cells against oxidative and endoplasmic reticulum stress. Therefore, TXNDC5 could serve as a viable biomarker or even a potential pharmacological target.

Loss of the endoplasmic reticulum protein Tmem208 affects cell polarity, development, and viability

Nascent proteins destined for the cell membrane and the secretory pathway are targeted to the endoplasmic reticulum (ER) either posttranslationally or cotranslationally. The signal-independent pathway, containing the protein TMEM208, is one of three pathways that facilitates the translocation of nascent proteins into the ER. The in vivo function of this protein is ill characterized in multicellular organisms. Here, we generated a CRISPR-induced null allele of the fruit fly ortholog CG8320/Tmem208 by replacing the gene with the Kozak-GAL4 sequence. We show that Tmem208 is broadly expressed in flies and that its loss causes lethality, although a few short-lived flies eclose. These animals exhibit wing and eye developmental defects consistent with impaired cell polarity and display mild ER stress. Tmem208 physically interacts with Frizzled (Fz), a planar cell polarity (PCP) receptor, and is required to maintain proper levels of Fz. Moreover, we identified a child with compound heterozygous variants in TMEM208 who presents with developmental delay, skeletal abnormalities, multiple hair whorls, cardiac, and neurological issues, symptoms that are associated with PCP defects in mice and humans. Additionally, fibroblasts of the proband display mild ER stress. Expression of the reference human TMEM208 in flies fully rescues the loss of Tmem208, and the two proband-specific variants fail to rescue, suggesting that they are loss-of-function alleles. In summary, our study uncovers a role of TMEM208 in development, shedding light on its significance in ER homeostasis and cell polarity.

Multidimensional comprehensive and integrated analysis of the potential function of TMEM25 in renal clear cell carcinoma with low expression status

BACKGROUND

Transmembrane 25(TMEM25) stands out as a potential prognostic biomarker and therapeutic target in the realm of cancer, yet its precise mechanism of action within clear cell renal cell carcinoma (ccRCC) remains unclear.

MATERIALS AND METHODS

Gene expression data and clinically relevant information extracted from The Cancer Genome Atlas (TCGA) and Gene expression omnibus (GEO) databases unveil the expression patterns of TMEM25 within renal clear cell carcinoma, which reveals its prognostic and diagnostic significance. The protein expression data is available via the Human Protein Atlas (HPA) database. Further, qPCR experiments conducted on cells and tissues provide strong evidence of the gene's expression status. Additionally, they explore the correlations between TMEM25 expression and DNA methylation, gene mutations, immune cell infiltration, and drug sensitivity within this specific tumor context.

RESULTS

At both the RNA and protein levels, TMEM25 displays a noteworthy downregulation in expression, which is consistently linked to an unfavorable prognosis. Receiver Operating Characteristic (ROC) curve analysis, univariate and multivariate Cox regression analyses confirmed the ability of TMEM25 to diagnose and determine prognosis in ccRCC. Its expression related closely with various immune cell types, immune checkpoints, immune inhibitors, and MHC molecules. Within ccRCC tissues, TMEM25 DNA methylation levels are observed to be elevated, and this upregulation is observed across various conditions. TMEM25 mutations also have an impact on the prognosis of ccRCC patients and the results of drug sensitivity analyses are useful for clinical decision-making.

CONCLUSIONS

TMEM25 in ccRCC could potentially function as a tumor suppressor gene, holding substantial promise as a novel biomarker for diagnosing, treating, and prognosticating ccRCC patients.

Genomic characterization and transcription analysis of European sea bass (Dicentrarchus labrax) rtp3 genes

Fish RTP3, belonging to the receptor-transporting protein family, display several functions, including a putative antiviral role as virus-responsive gene. In this work, we have identified and characterized two different European sea bass rtp3 genes. In addition, an in vivo transcription analysis in response to LPS, poly I:C and betanodavirus infection (RGNNV genotype) has been performed. The sequence analysis showed that European sea bass displays two rtp3 genes, X1 and X2, composed of two exons and a single intron (1007-bp and 888-bp long, respectively), located within the ORF sequence. The full-length cDNA is 1969 bp for rtp3 X1, and 1491 bp for rtp3 X2. Several ATTTA motifs have been found in the intron sequence of both genes, whereas rtp3 X1 also contains this motif in both untranslated regions. The transcription analyses revealed significant level of rtp3 X2 mRNA in brain and head kidney after LPS and poly I:C inoculation; however, the induction elicited by RGNNV infection was much higher, suggesting an essential role for this protein in controlling NNV infections.

The transmembrane proteins (TMEM) and their role in cell proliferation, migration, invasion, and epithelial-mesenchymal transition in cancer

Transmembrane proteins (TMEM) are located in the different biological membranes of the cell and have at least one passage through these cellular compartments. TMEM proteins carry out a wide variety of functions necessary to maintain cell homeostasis TMEM165 participates in glycosylation protein, TMEM88 in the development of cardiomyocytes, TMEM45A in epidermal keratinization, and TMEM74 regulating autophagy. However, for many TMEM proteins, their physiological function remains unknown. The role of these proteins is being recently investigated in cancer since transcriptomic and proteomic studies have revealed that exits differential expression of TMEM proteins in different neoplasms concerning cancer-free tissues. Among the cellular processes in which TMEM proteins have been involved in cancer are the promotion or suppression of cell proliferation, epithelial-mesenchymal transition, invasion, migration, intravasation/extravasation, metastasis, modulation of the immune response, and response to antineoplastic drugs. Inclusive data suggests that the participation of TMEM proteins in these cellular events could be carried out through involvement in different cell signaling pathways. However, the exact mechanisms not clear. This review shows a description of the involvement of TMEM proteins that promote or decrease cell proliferation, migration, and invasion in cancer cells, describes those TMEM proteins for which both a tumor suppressor and a tumor promoter role have been identified, depending on the type of cancer in which the protein is expressed. As well as some TMEM proteins involved in chemoresistance. A better characterization of these proteins is required to improve the understanding of the tumors in which their expression and function are altered; in addition to improving the understanding of the role of these proteins in cancer will show those TMEM proteins be potential candidates as biomarkers of response to chemotherapy or prognostic biomarkers or as potential therapeutic targets in cancer.

TMEM232 promotes the inflammatory response in atopic dermatitis via the nuclear factor-κB and signal transducer and activator of transcription 3 signalling pathways

BACKGROUND

Our group previously found that the transmembrane protein 232 (TMEM232) gene was associated with atopic dermatitis (AD) by genome-wide association study and fine mapping study. However, its function is unclear so far.

OBJECTIVES

To investigate the roles and mechanisms of TMEM232 in AD.

METHODS

The expression of TMEM232 was investigated in skin lesions of patients with AD, the MC903-induced AD mouse model, human primary keratinocytes and immortalized human keratinocyte cell line (HaCaT) cells stimulated with different inflammatory factors. The role of TMEM232 in AD was analysed in HaCaT cells and Tmem232 knockout (Tmem232-/-) mice. Tmem232-specific small interfering RNA (siRNA) was used to evaluate its therapeutic potential in the AD mouse model.

RESULTS

The expression of TMEM232 was significantly increased in skin lesions of patients with AD, the MC903-induced AD mouse model and human primary keratinocytes and HaCaT cells stimulated with different inflammatory factors compared with controls. In the presence of MC903, Tmem232-/- mice exhibited significantly reduced dermatitis severity, mast-cell infiltration in the back, and expression of T-helper (Th)1 and Th2-related inflammatory factors in skin tissue compared with wild-type mice. In vitro and in vivo experiments further showed that upregulation of TMEM232 in AD exacerbated the inflammation response through activating the pathway of nuclear factor-κB and signal transducer and activator of transcription (STAT) 3, and was regulated by the interleukin-4/STAT6 axis, which formed a self-amplifying loop. Finally, topical application of Tmem232 siRNA markedly ameliorated AD-like lesions in the AD model.

CONCLUSIONS

This study is the first to outline the function of TMEM232. It is involved in regulating inflammation in AD and may be a potential target for AD treatment.

TMEM11 regulates cardiomyocyte proliferation and cardiac repair via METTL1-mediated m7G methylation of ATF5 mRNA

The mitochondrial transmembrane (TMEM) protein family has several essential physiological functions. However, its roles in cardiomyocyte proliferation and cardiac regeneration remain unclear. Here, we detected that TMEM11 inhibits cardiomyocyte proliferation and cardiac regeneration in vitro. TMEM11 deletion enhanced cardiomyocyte proliferation and restored heart function after myocardial injury. In contrast, TMEM11-overexpression inhibited neonatal cardiomyocyte proliferation and regeneration in mouse hearts. TMEM11 directly interacted with METTL1 and enhanced m⁷G methylation of Atf5 mRNA, thereby increasing ATF5 expression. A TMEM11-dependent increase in ATF5 promoted the transcription of Inca1, an inhibitor of cyclin-dependent kinase interacting with cyclin A1, which suppressed cardiomyocyte proliferation. Hence, our findings revealed that TMEM11-mediated m⁷G methylation is involved in the regulation of cardiomyocyte proliferation, and targeting the TMEM11-METTL1-ATF5-INCA1 axis may serve as a novel therapeutic strategy for promoting cardiac repair and regeneration.

Structural, topological, and functional characterization of transmembrane proteins TMEM213, 207, 116, 72 and 30B provides a potential link to ccRCC etiology

Due to their involvement in the development of various cancers Transmembrane Proteins (TMEMs) are the focus of many recent studies. Previously we reported TMEM de-regulation in clear cell Renal Cell Carcinoma (ccRCC) with TMEM213, 207, 116, 72 and 30B being among the most downregulated on mRNA level. TMEM down-regulation was also more pronounced in advanced ccRCC tumors and was potentially linked to clinical parameters such as: metastasis (TMEM72 and 116), Fuhrman grade (TMEM30B) and overall survival (TMEM30B). To further investigate these findings, first, we set off to prove experimentally that selected TMEMs are indeed membrane-bound as predicted in silico, we verified the presence of signaling peptides on their N-termini, orientation of TMEMs within the membrane and validated their predicted cellular localization. To investigate the potential role of selected TMEMs in cellular processes overexpression studies in HEK293 and HK-2 cell lines were carried out. Additionally, we tested TMEM isoform expression in ccRCC tumors, identified mutations in TMEM genes and examined chromosomal aberrations in their loci. We confirmed the membrane-bound status of all selected TMEMs, assigned TMEM213, and 207 to early endosomes, TMEM72 to early endosomes and plasma membrane, TMEM116 and 30B to the endoplasmic reticulum. The N-terminus of TMEM213 was found to be exposed to the cytoplasm, the C-terminus of TMEM207, 116 and 72 were directed toward the cytoplasm, and both termini of TMEM30B faced the cytoplasm. Interestingly, TMEM mutations and chromosomal aberrations were infrequent in ccRCC tumors, yet we identified potentially damaging mutations in TMEM213 and TMEM30B and found deletions in the TMEM30B locus in nearly 30% of the tumors. Overexpression studies suggested selected TMEMs may take part in carcinogenesis processes such as cell adhesion, regulation of epithelial cell proliferation, and regulation of adaptive immune response, which could indicate a link to the development and progression of ccRCC.

TMEM196 inhibits lung cancer metastasis by regulating the Wnt/β-catenin signaling pathway

PURPOSE

The TMEM196 protein, which comprises four membrane-spanning domains, belongs to the TMEM protein family. TMEM196 was identified as a candidate tumor suppressor gene in lung cancer. However, its role and mechanism in lung cancer metastasis remain unclear. Here, we study the role of TMEM196 in tumor metastasis to further verify the function in lung cancer.

METHODS

In this study, we used qRT-PCR, western blot analysis and immunohistochemistry to examine the expression levels of TMEM196 and related proteins in lung cancer tissues and tumor cells. We utilized Transwell assays, xenograft nude mouse models, and TMEM196^-/- mouse models to evaluate the effects of TMEM196 on tumor invasion and metastasis. Finally, we used bioinformatics analysis and dual-luciferase reporter gene assays to explore the molecular mechanism of TMEM196 as a tumor suppressor.

RESULTS

We found that TMEM196 mRNA and protein expression levels were significantly decreased in lung cancer tissues and cells. Low expression of TMEM196 in clinical patients was associated with poor prognosis. TMEM196 strongly inhibited tumor metastasis and progression in vitro and in vivo. The primary lung tumors induced by tail vein-inoculated B16 cells in TMEM196^-/- mice were significantly larger than those in TMEM196^+/+ mice. Mechanistically, TMEM196 inhibited the Wnt signaling pathway and repressed β-catenin promoter transcription. TMEM196 silencing in lung cancer cells and mice resulted in significant upregulation of the expression of β-catenin and Wnt signaling pathway downstream target genes (MMP2 and MMP7). Decreasing β-catenin expression in TMEM196-silenced cancer cells attenuated the antimetastatic effect of TMEM196.

CONCLUSIONS

Our results revealed that TMEM196 acts as a novel lung cancer metastasis suppressor via the Wnt/β-catenin signaling pathway.

Characterization of cellular senescence patterns predicts the prognosis and therapeutic response of hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is a prevalent malignancy with a high mortality rate. Cellular senescence, an irreversible state of cell cycle arrest, plays a paradoxical role in cancer progression. Here, we aimed to identify Hepatocellular carcinoma subtypes by cellular senescence-related genes (CSGs) and to construct a cellular senescence-related gene subtype predictor as well as a novel prognostic scoring system, which was expected to predict clinical outcomes and therapeutic response of Hepatocellular carcinoma. Methods: RNA-seq data and clinical information of Hepatocellular carcinoma patients were derived from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC). The "multi-split" selection was used to screen the robust prognostic cellular senescence-related genes. Unsupervised clustering was performed to identify CSGs-related subtypes and a discriminant model was obtained through multiple statistical approaches. A CSGs-based prognostic model-CSGscore, was constructed by LASSO-Cox regression and stepwise regression. Immunophenoscore (IPS) and Tumor Immune Dysfunction and Exclusion (TIDE) were utilized to evaluate the immunotherapy response. Tumor stemness indices mRNAsi and mDNAsi were used to analyze the relationship between CSGscore and stemness. Results: 238 robust prognostic differentially expressed cellular senescence-related genes (DECSGs) were used to categorize all 336 hepatocellular carcinoma patients of the TCGA-LIHC cohort into two groups with different survival. Two hub genes, TOP2A and KIF11 were confirmed as key indicators and were used to form a precise and concise cellular senescence-related gene subtype predictor. Five genes (PSRC1, SOCS2, TMEM45A, CCT5, and STC2) were selected from the TCGA training dataset to construct the prognostic CSGscore signature, which could precisely predict the prognosis of hepatocellular carcinoma patients both in the training and validation datasets. Multivariate analysis verified it as an independent prognostic factor. Besides, CSGscore was also a valuable predictor of therapeutic responses in hepatocellular carcinoma. More downstream analysis revealed the signature genes were significantly associated with stemness and tumor progression. Conclusion: Two subtypes with divergent outcomes were identified by prognostic cellular senescence-related genes and based on that, a subtype indicator was established. Moreover, a prognostic CSGscore system was constructed to predict the survival outcomes and sensitivity of therapeutic responses in hepatocellular carcinoma, providing novel insight into hepatocellular carcinoma biomarkers investigation and design of tailored treatments depending on the molecular characteristics of individual patients.

Tmem45b is essential for inflammation- and tissue injury-induced mechanical pain hypersensitivity

Persistent mechanical pain hypersensitivity associated with peripheral inflammation, surgery, trauma, and nerve injury impairs patients' quality of life and daily activity. However, the molecular mechanism and treatment are not yet fully understood. Herein, we show that chemical ablation of isolectin B4-binding (IB4⁺) afferents by IB4-saporin injection into sciatic nerves completely and selectively inhibited inflammation- and tissue injury-induced mechanical pain hypersensitivity while thermal and mechanical pain hypersensitivities were normal following nerve injury. To determine the molecular mechanism involving the specific types of mechanical pain hypersensitivity, we compared gene expression profiles between IB4⁺ neuron-ablated and control dorsal root ganglion (DRG) neurons. We identified Tmem45b as one of 12 candidate genes that were specific to somatosensory ganglia and down-regulated by IB4⁺ neuronal ablation. Indeed, Tmem45b was expressed predominantly in IB4⁺ DRG neurons, where it was selectively localized in the trans Golgi apparatus of DRG neurons but not detectable in the peripheral and central branches of DRG axons. Tmem45b expression was barely detected in the spinal cord and brain. Although Tmem45b-knockout mice showed normal responses to noxious heat and noxious mechanical stimuli under normal conditions, mechanical pain hypersensitivity was selectively impaired after inflammation and tissue incision, reproducing the pain phenotype of IB4⁺ sensory neuron-ablated mice. Furthermore, acute knockdown by intrathecal injection of Tmem45b small interfering RNA, either before or after inflammation induction, successfully reduced mechanical pain hypersensitivity. Thus, our study demonstrates that Tmem45b is essential for inflammation- and tissue injury-induced mechanical pain hypersensitivity and highlights Tmem45b as a therapeutic target for future treatment.

A novel amino acid metabolism-related gene risk signature for predicting prognosis in clear cell renal cell carcinoma

Background

Renal cancer is one of the most lethal cancers because of its atypical symptoms and metastatic potential. The metabolism of amino acids and their derivatives is essential for cancer cell survival and proliferation. Thus, the construction of the amino acid metabolism-related risk signature might enhance the accuracy of the prognostic model and shed light on the treatments of renal cancers.

Methods

RNA expression and clinical data were downloaded from Santa Cruz (UCSC) Xena, GEO, and ArrayExpress databases. The “DESeq2” package identified the differentially expressed genes. Univariate COX analysis selected prognostic genes related to the metabolism of amino acids. Patients were divided into two clusters using the “ConsensusClusterPlus” package, and the CIBERSORT, ESTIMATE methods were explored to assess the immune infiltrations. The LASSO regression analysis constructed a risk model which was evaluated the prediction accuracy in two independent cohorts. The genomic alterations and drug sensitivity of 18-LASSO-genes were assessed. The differentially expressed genes between two clusters were used to perform functional enrichment analysis and weighted gene co-expression network analysis (WGCNA). Furthermore, external validation of TMEM72 expression was conducted in the FUSCC cohort containing 33 ccRCC patients.

Results

The amino acid metabolism-related genes had significant correlations with prognosis. The patients in Cluster A demonstrated better survival, lower Treg cell proportion, higher ESTIMATE scores, and higher cuproptosis-related gene expressions. Amino acid metabolism-related genes with prognostic values were used to construct a risk model and patients in the low risk group were associated with improved outcomes. The Area Under Curve of the risk model was 0.801, 0.777, and 0.767 at the first, second, and third year respectively. The external validation cohort confirmed the stable prognostic value of the risk model. WGCNA identified four gene modules correlated with immune cell infiltrations and cuproptosis. We found that TMEM72 was downregulated in tumors by using TCGA, GEO datasets (p<0.001) and the FUSCC cohort (p=0.002).

Conclusion

Our study firstly constructed an 18 amino acid metabolism related signature to predict the prognosis in clear cell renal cell carcinoma. We also identified four potential gene modules potentially correlated with cuproptosis and identified TMEM72 downregulation in ccRCC which deserved further studies.

Membrane Localized GbTMEM214s Participate in Modulating Cotton Resistance to Verticillium Wilt

Verticillium wilt (VW) is a soil-borne fungal disease caused by Verticillium dahliae Kleb, which leads to serious damage to cotton production annually in the world. In our previous study, a transmembrane protein 214 protein (TMEM214) gene associated with VW resistance was map-based cloned from Gossypium barbadense (G. barbadense). TMEM214 proteins are a kind of transmembrane protein, but their function in plants is rarely studied. To reveal the function of TMEM214s in VW resistance, all six TMEM214s were cloned from G. barbadense in this study. These genes were named as GbTMEM214-1_A/D, GbTMEM214-4_A/D and GbTMEM214-7_A/D, according to their location on the chromosomes. The encoded proteins are all located on the cell membrane. TMEM214 genes were all induced with Verticillium dahliae inoculation and showed significant differences between resistant and susceptible varieties, but the expression patterns of GbTMEM214s under different hormone treatments were significantly different. Virus-induced gene silencing analysis showed the resistance to VW of GbTMEM214s-silenced lines decreased significantly, which further proves the important role of GbTMEM214s in the resistance to Verticillium dahliae. Our study provides an insight into the involvement of GbTMEM214s in VW resistance, which was helpful to better understand the disease-resistance mechanism of plants.

Comprehensive RNA-seq reveals molecular changes in kidney malignancy among people living with HIV

To heighten the awareness of kidney malignancy in patients with HIV infection to facilitate the early diagnosis of kidney cancer, the differentially expressed mRNAs were analyzed in this malignant tumor using RNA sequencing. We identified 2,962 protein-coding transcripts in HIV-associated kidney cancer. KISS1R, CAIX, and NPTX2 mRNA expression levels were specifically increased in HIV-associated kidney cancer while UMOD and TMEM213 mRNA were decreased in most cases based on real-time PCR analyses. These findings were similar to those noted for the general population with renal cell carcinoma. Immunohistochemical staining analysis also showed that a total of 18 malignant kidney cases among the people living with HIV (PLWH) exhibited positive staining for KISS1R and CAIX. Pathway analysis of the differentially expressed mRNAs in HIV-associated kidney cancer revealed that several key pathways were involved, including vascular endothelial growth factor-activated receptor activity, IgG binding, and lipopolysaccharide receptor activity. Altogether, our findings reveal the identified molecular changes in kidney malignancy, which may offer a helpful explanation for cancer progression and open up new therapeutic avenues that may decrease mortality after a cancer diagnosis among PLWH.

Early Deregulation of Cholangiocyte NR0B2 During Primary Sclerosing Cholangitis

Background and Aims

Primary sclerosing cholangitis (PSC) is a probable autoimmune liver disease characterized by persistent and progressive biliary inflammation that leads to biliary infection, cirrhosis, or cholangiocarcinoma. Genome-wide omics data are scarce regarding this severe disease.

Methods

MEDLINE database gene prioritization by text mining (biliary inflammation, biliary fibrosis, biliary stasis) was integrated in distinct omics data: (1) PSC liver transcriptome training and validation cohorts, (2) farnesoid X receptor (FXR) mice liver transcriptome subjected to an FXR agonist or FXR knockout mice; (3) liver single-cell transcriptome of the Abcb4-/- mice model of PSC.

Results

A liver molecular network highlighted the involvement of nuclear receptor subfamily 0 group B member 2 (NR0B2) and its associated nuclear receptor FXR in a metabolic cascade that may influence the immune response. NR0B2 upregulation in PSC liver was independent of gender, age, body mass index, liver fibrosis, and PSC complications. Heterogeneity of NR0B2 upregulation was found in cholangiocyte cell types in which the NR0B2-based cell fate decision revealed the involvement of several metabolic pathways for detoxification (sulfur, glutathione derivative, and monocarboxylic acid metabolisms). Genes potentially implicated in carcinogenesis were also discovered on this cholangiocyte trajectory: GSTA3, inhibitor of DNA binding 2, and above all, TMEM45A, a transmembrane molecule from the Golgi apparatus considered as oncogenic in several cancers.

Conclusion

By revisiting PSC through PubMed data mining, we evidenced the early cholangiocyte deregulation of NR0B2, highlighting a metabolic and premalignant reprogramming of the cholangiocyte cell type. The therapeutic targeting of NR0B2 could potentiate that of FXR and enable action on early events of the disease and prevent its progression.

AKT1 Transcriptomic Landscape in Breast Cancer Cells

Overexpression and hyperactivation of the serine/threonine protein kinase B (AKT) pathway is one of the most common cellular events in breast cancer progression. However, the nature of AKT1-specific genome-wide transcriptomic alterations in breast cancer cells and breast cancer remains unknown to this point. Here, we delineate the impact of selective AKT1 knock down using gene-specific siRNAs or inhibiting the AKT activity with a pan-AKT inhibitor VIII on the nature of transcriptomic changes in breast cancer cells using the genome-wide RNA-sequencing analysis. We found that changes in the cellular levels of AKT1 lead to changes in the levels of a set of differentially expressed genes and, in turn, imply resulting AKT1 cellular functions. In addition to an expected positive relationship between the status of AKT1 and co-expressed cellular genes, our study unexpectedly discovered an inherent role of AKT1 in inhibiting the expression of a subset of genes in both unstimulated and growth factor stimulated breast cancer cells. We found that depletion of AKT1 leads to upregulation of a subset of genes—many of which are also found to be downregulated in breast tumors with elevated high AKT1 as well as upregulated in breast tumors with no detectable AKT expression. Representative experimental validation studies in two breast cancer cell lines showed a reasonable concurrence between the expression data from the RNA-sequencing and qRT-PCR or data from ex vivo inhibition of AKT1 activity in cancer patient-derived cells. In brief, findings presented here provide a resource for further understanding of AKT1-dependent modulation of gene expression in breast cancer cells and broaden the scope and significance of AKT1 targets and their functions.

Expression and prognostic potential of TMEM204: a pan-cancer analysis

TMEM204 (Transmembrane Protein 204) is a member of the TMEM family that regulates cell function and angiogenesis. Previous studies showed that TMEM204 is related to pancreatic cancer, but its roles in other cancers remain unknown. To reveal this relationship, we conducted a pan-cancer analysis by several online databases. The expression of TMEM204 was analyzed by Oncomine and Tumor Immune Estimation Resource2.0 (TIMER2.0). The prognostic potential of TMEM204 was evaluated by the GEPIA2, UALCAN, and Oncolnc. The methylation level of gene expression was analyzed by UALCAN, and the relationship between cancer and immune invasion was displayed by TIMER2.0. The Protein-Protein Interactions Network and functional analysis of TMEM204 and its related genes were conducted by STRING and Webgestalt. We found that TMEM204 expression was up-regulated and correlated with prognosis in multiple cancers. In liver hepatocellular carcinoma (LIHC), high TMEM204 expression was associated with a good prognosis, and with high infiltrating levels of CD8⁺ T and CD4⁺ T cells, macrophages, neutrophils, and myeloid dendritic cells. In addition, the methylation level in LIHC was higher than in normal tissues. p53 signaling pathway and Fanconi anemia pathway were implicated by KEGG pathway analysis. These results indicate that TMEM204 is associated with the prognosis, methylation, and immune invasion of cancers, especially LIHC. TMEM204 may act as a prognostic marker of LIHC and its role in other cancers should be studied.

Computational Analysis Identifies Novel Biomarkers for High-Risk Bladder Cancer Patients

In the case of bladder cancer, carcinoma in situ (CIS) is known to have poor diagnosis. However, there are not enough studies that examine the biomarkers relevant to CIS development. Omics experiments generate data with tens of thousands of descriptive variables, e.g., gene expression levels. Often, many of these descriptive variables are identified as somehow relevant, resulting in hundreds or thousands of relevant variables for building models or for further data analysis. We analyze one such dataset describing patients with bladder cancer, mostly non-muscle-invasive (NMIBC), and propose a novel approach to feature selection. This approach returns high-quality features for prediction and yet allows interpretability as well as a certain level of insight into the analyzed data. As a result, we obtain a small set of seven of the most-useful biomarkers for diagnostics. They can also be used to build tests that avoid the costly and time-consuming existing methods. We summarize the current biological knowledge of the chosen biomarkers and contrast it with our findings.

A novel DNA methylation-driver gene signature for long-term survival prediction of hepatitis-positive hepatocellular carcinoma patients

BACKGROUND

Abnormal DNA methylation is one of the most general epigenetic modifications in hepatocellular carcinoma (HCC). Recent research showed that DNA methylation was a prognostic indicator of all-cause HCC and nonviral HCC. However, whether DNA methylation-driver genes could be used for predicting survival, the probability of hepatitis-positive HCC remains unclear.

METHODS

In this study, DNA methylation-driver genes (MDGs) were screened by a joint analysis of methylome and transcriptome data of 142 hepatitis-positive HCC patients. Subsequently, a prognostic risk score and nomogram were constructed. Finally, correlation analyses between the risk score and signaling pathways and immunity were conducted by GSVA and CIBERSORT.

RESULTS

Through random forest screening and Cox progression analysis, 10 prognostic methylation-driver genes (AC008271.1, C11orf53, CASP8, F2RL2, GBP5, LUCAT1, RP11-114B7.6, RP11-149I23.3, RP11-383 J24.1, and SLC35G2) were screened out. As a result, a prognostic risk score signature was constructed. The independent value of the risk score for prognosis prediction were addressed in the TCGA-HCC and the China-HCC cohorts. Next, clinicopathological features were analyzed and HBV status and histological grade were screened to construct a nomogram together with the risk score. The prognostic efficiency of the nomogram was validated by the calibration curves and the concordance index (C index: 0.829, 95% confidence interval: 0.794-0.864), while its clinical application ability was confirmed by decision curve analysis (DCA). At last, the relationship between the risk score and signaling pathways, as well as the correlations between immune cells were elucidated preliminary.

CONCLUSIONS

Taken together, our study explored a novel DNA methylation-driver gene risk score signature and an efficient nomogram for long-term survival prediction of hepatitis-positive HCC patients.

Knockdown of NAA25 Suppresses Breast Cancer Progression by Regulating Apoptosis and Cell Cycle

NAA25 gene variants were reported as risk factors for type 1 diabetes, rheumatoid arthritis and acute arterial stroke. But it’s unknown whether it could contribute to breast cancer. We identified rs11066150 in lncHSAT164, which contributes to breast cancer, in our earlier genome-wide long non-coding RNA association study on Han Chinese women. However, rs11066150 A/G variant is also located in NAA25 intron. Based on the public database, such as TCGA and Curtis dataset, NAA25 gene is highly expressed in breast cancer tissues and this result has also been proved in our samples and cell lines through RT-qPCR and western blot analysis. To better understand the function of NAA25 in breast cancer, we knocked down the expression of NAA25 in breast cancer cell lines, FACS was used to detect cell apoptosis and cell cycle and colony formation assay was used to detect cell proliferation. We found that NAA25-deficient cells could increase cell apoptosis, delay G2/M phase cell and decrease cell clone formation. RNA sequencing was then applied to analyze the molecular profiles of NAA25−deficient cells, and compared to the control group, NAA25 knockdown could activate apoptosis-related pathways, reduce the activation of tumor-associated signaling pathways and decrease immune response-associated pathways. Additionally, RT-qPCR was employed to validate these results. Taken together, our results revealed that NAA25 was highly expressed in breast cancer, and NAA25 knockdown might serve as a therapeutic target in breast cancer.

Analysis of the Single-Cell Heterogeneity of Adenocarcinoma Cell Lines and the Investigation of Intratumor Heterogeneity Reveals the Expression of Transmembrane Protein 45A (TMEM45A) in Lung Adenocarcinoma Cancer Patients

Simple Summary

Non-small cell lung cancer (NSCLC) is one of the main causes of cancer-related deaths worldwide. Intratumoral heterogeneity (ITH) is responsible for the majority of difficulties encountered in the treatment of lung-cancer patients. Therefore, the heterogeneity of NSCLC cell lines and primary lung adenocarcinoma was investigated by single-cell mass cytometry (CyTOF). Human NSCLC adenocarcinoma cells A549, H1975, and H1650 were studied at single-cell resolution for the expression pattern of 13 markers: GLUT1, MCT4, CA9, TMEM45A, CD66, CD274, CD24, CD326, pan-keratin, TRA-1-60, galectin-3, galectin-1, and EGFR. The intra- and inter-cell-line heterogeneity of A549, H1975, and H1650 cells were demonstrated through hypoxic modeling. Additionally, human primary lung adenocarcinoma, and non-involved healthy lung tissue were homogenized to prepare a single-cell suspension for CyTOF analysis. The single-cell heterogeneity was confirmed using unsupervised viSNE and FlowSOM analysis. Our results also show, for the first time, that TMEM45A is expressed in lung adenocarcinoma.

Abstract

Intratumoral heterogeneity (ITH) is responsible for the majority of difficulties encountered in the treatment of lung-cancer patients. Therefore, the heterogeneity of NSCLC cell lines and primary lung adenocarcinoma was investigated by single-cell mass cytometry (CyTOF). First, we studied the single-cell heterogeneity of frequent NSCLC adenocarcinoma models, such as A549, H1975, and H1650. The intra- and inter-cell-line single-cell heterogeneity is represented in the expression patterns of 13 markers—namely GLUT1, MCT4, CA9, TMEM45A, CD66, CD274 (PD-L1), CD24, CD326 (EpCAM), pan-keratin, TRA-1-60, galectin-3, galectin-1, and EGFR. The qRT-PCR and CyTOF analyses revealed that a hypoxic microenvironment and altered metabolism may influence cell-line heterogeneity. Additionally, human primary lung adenocarcinoma and non-involved healthy lung tissue biopsies were homogenized to prepare a single-cell suspension for CyTOF analysis. The CyTOF showed the ITH of human primary lung adenocarcinoma for 14 markers; particularly, the higher expressions of GLUT1, MCT4, CA9, TMEM45A, and CD66 were associated with the lung-tumor tissue. Our single-cell results are the first to demonstrate TMEM45A expression in human lung adenocarcinoma, which was verified by immunohistochemistry.

TMEM116 is required for lung cancer cell motility and metastasis through PDK1 signaling pathway

Transmembrane protein (TMEM) is a family of protein that spans cytoplasmic membranes and allows cell-cell and cell-environment communication. Dysregulation of TMEMs has been observed in multiple cancers. However, little is known about TMEM116 in cancer development. In this study, we demonstrate that TMEM116 is highly expressed in non-small-cell lung cancer (NSCLC) tissues and cell lines. Inactivation of TMEM116 reduced cell proliferation, migration and invasiveness of human cancer cells and suppressed A549 induced tumor metastasis in mouse lungs. In addition, TMEM116 deficiency inhibited PDK1-AKT-FOXO3A signaling pathway, resulting in accumulation of TAp63, while activation of PDK1 largely reversed the TMEM116 deficiency induced defects in cancer cell motility, migration and invasive. Together, these results demonstrate that TMEM116 is a critical integrator of oncogenic signaling in cancer metastasis.

Confirming the TMEM232 gene associated with atopic dermatitis through targeted capture sequencing

Atopic dermatitis (AD) is a common and complex skin disorder, and the 5q22.1 region had been reported to be associated with AD. To confirm the susceptibility gene for AD in the 5q22.1 region by haplotype and targeted capture sequencing. The haplotypes were reconstructed with the genotyping data of four SNPs and six deletions from 3624 Chinese Hans AD patients and 5076 controls. The targeted capture sequencing spanning 5q22.1 region was performed in the selected samples. The gene level enrichment analysis was done using loss of function variants. A total of 62 haplotypes were found, and the H15 haplotype had the strongest association with AD (P = 3.92 × 10^-10, OR 0.17, 95% CI 0.09-0.32). However, no co-segregation mutation sites were found in the sequencing analysis within the 16 selected samples, while the enrichment analysis indicated that TMEM232 was significantly associated with AD (P = 7.33 × 10^-5, OR 0.33, 95% CI 0.19-0.58). This study confirms previous findings that the TMEM232 gene is associated with AD by haplotype analysis and targeted capture sequencing.

The cell surface hyaluronidase TMEM2 is essential for systemic hyaluronan catabolism and turnover

As a major component of the extracellular matrix, hyaluronan (HA) plays an important role in defining the biochemical and biophysical properties of tissues. In light of the extremely rapid turnover of HA and the impact of this turnover on HA biology, elucidating the molecular mechanisms underlying HA catabolism is key to understanding the in vivo functions of this unique polysaccharide. Here, we show that TMEM2, a recently identified cell surface hyaluronidase, plays an essential role in systemic HA turnover. Employing induced global Tmem2 knockout mice (Tmem2iKO), we determined the effects of Tmem2 ablation not only on the accumulation of HA in bodily fluids and organs, but also on the process of HA degradation in vivo. Within 3 weeks of tamoxifen-induced Tmem2 ablation, Tmem2iKO mice exhibit pronounced accumulation of HA in circulating blood and various organs, reaching levels as high as 40-fold above levels observed in control mice. Experiments using lymphatic and vascular injection of fluorescent HA tracers demonstrate that ongoing HA degradation in the lymphatic system and the liver is significantly impaired in Tmem2iKO mice. We also show that Tmem2 is strongly expressed in endothelial cells in the subcapsular sinus of lymph nodes and in the liver sinusoid, two primary sites implicated in systemic HA turnover. Our results establish TMEM2 as a physiologically relevant hyaluronidase with an essential role in systemic HA catabolism in vivo, acting primarily on the surface of endothelial cells in the lymph nodes and liver.

The Landscape of Transmembrane Protein Family Members in Head and Neck Cancers: Their Biological Role and Diagnostic Utility

Simple Summary

Transmembrane proteins (TMEM) are a large group of integral membrane proteins whose molecular and biological functions are not fully understood. It is known that some of them are involved in tumor formation and metastasis. Here, we performed a panel of TCGA data analyses to investigate the role of different TMEM genes in head and neck squamous cell carcinoma (HNSCC) and define their potential as biomarkers. Based on changes in the expression levels in HNSCC tumors, we selected four TMEM genes: ANO1, TMEM156, TMEM173, and TMEM213 and associated them with patient survival. We also demonstrated that the expression of those TMEMs highly correlates with the enrichment of genes involved in numerous biological processes, especially metastasis formation and immune response. Thus, we propose ANO1, TMEM156, TMEM173, and TMEM213 as new biomarkers and potential targets for personalized therapy of HNSCC.

Abstract

Background: Transmembrane proteins (TMEM) constitute a large family of proteins spanning the entirety of the lipid bilayer. However, there is still a lack of knowledge about their function or mechanism of action. In this study, we analyzed the expression of selected TMEM genes in patients with head and neck squamous cell carcinoma (HNSCC) to learn their role in tumor formation and metastasis. Materials and Methods: Using TCGA data, we analyzed the expression levels of different TMEMs in both normal and tumor samples and compared those two groups depending on clinical-pathological parameters. We selected four TMEMs whose expression was highly correlated with patient survival status and subjected them to further analysis. The pathway analysis using REACTOME and the gene set enrichment analysis (GSEA) were performed to evaluate the association of those TMEMs with genes involved in hallmarks of cancer as well as in oncogenic and immune-related pathways. In addition, the fractions of different immune cell subpopulations depending on TMEM expression were estimated in analyzed patients. The results for selected TMEMs were validated using GEO data. All analyses were performed using the R package, Statistica, and Graphpad Prism. Results: We demonstrated that 73% of the analyzed TMEMs were dysregulated in HNSCC and depended on tumor localization, smoking, alcohol consumption, or HPV infection. The expression levels of ANO1, TMEM156, TMEM173, and TMEM213 correlated with patient survival. The four TMEMs were also upregulated in HPV-positive patients. The elevated expression of those TMEMs correlated with the enrichment of genes involved in cancer-related processes, including immune response. Specifically, overexpression of TMEM156 and TMEM173 was associated with immune cell mobilization and better survival rates, while the elevated ANO1 expression was linked with metastasis formation and worse survival. Conclusions: In this work, we performed a panel of in silico analyses to discover the role of TMEMs in head and neck squamous cell carcinoma. We found that ANO1, TMEM156, TMEM173, and TMEM213 correlated with clinical status and immune responses in HNSCC patients, pointing them as biomarkers for a better prognosis and treatment. This is the first study describing such the role of TMEMs in HNSCC. Future clinical trials should confirm the potential of those genes as targets for personalized therapy of HNSCC.

Cobalt-induced oxidative stress contributes to alveolar/bronchiolar carcinogenesis in B6C3F1/N mice

Rodent alveolar/bronchiolar carcinomas (ABC) that arise either spontaneously or due to chemical exposure are similar to a subtype of lung adenocarcinomas in humans. B6C3F1/N mice and F344/NTac rats exposed to cobalt metal dust (CMD) by inhalation developed ABCs in a dose dependent manner. In CMD-exposed mice, the incidence of Kras mutations in ABCs was 67% with 80% of those being G to T transversions on codon 12 suggesting a role of oxidative stress in the pathogenesis. In vitro studies, such as DMPO (5,5-dimethyl-1-pyrroline N-oxide) immune-spin trapping assay, and dihydroethidium (DHE) fluorescence assay on A549 and BEAS-2B cells demonstrated increased oxidative stress due to cobalt exposure. In addition, significantly increased 8-oxo-dG adducts were demonstrated by immunohistochemistry in lungs from mice exposed to CMD for 90 days. Furthermore, transcriptomic analysis on ABCs arising spontaneously or due to chronic CMD-exposure demonstrated significant alterations in canonical pathways related to MAPK signaling (IL-8, ErbB, Integrin, and PAK pathway) and oxidative stress (PI3K/AKT and Melatonin pathway) in ABCs from CMD-exposed mice. Oxidative stress can stimulate PI3K/AKT and MAPK signaling pathways. Nox4 was significantly upregulated only in CMD-exposed ABCs and NOX4 activation of PI3K/AKT can lead to increased ROS levels in human cancer cells. The gene encoding Ereg was markedly up-regulated in CMD-exposed mice. Oncogenic KRAS mutations have been shown to induce EREG overexpression. Collectively, all these data suggest that oxidative stress plays a significant role in CMD-induced pulmonary carcinogenesis in rodents and these findings may also be relevant in the context of human lung cancers.

A Claudin-Based Molecular Signature Identifies High-Risk, Chemoresistant Colorectal Cancer Patients

Identifying molecular characteristics that are associated with aggressive cancer phenotypes through gene expression profiling can help predict treatment responses and clinical outcomes. Claudins are deregulated in colorectal cancer (CRC). In CRC, increased claudin-1 expression results in epithelial-to-mesenchymal transition and metastasis, while claudin-7 functions as a tumor suppressor. In this study, we have developed a molecular signature based on claudin-1 and claudin-7 associated with poor patient survival and chemoresistance. This signature was validated using an integrated approach including publicly available datasets and CRC samples from patients who either responded or did not respond to standard-of-care treatment, CRC cell lines, and patient-derived rectal and colon tumoroids. Transcriptomic analysis from a patient dataset initially yielded 23 genes that were differentially expressed along with higher claudin-1 and decreased claudin-7. From this analysis, we selected a claudins-associated molecular signature including PIK3CA, SLC6A6, TMEM43, and ASAP-1 based on their importance in CRC. The upregulation of these genes and their protein products was validated using multiple CRC patient datasets, in vitro chemoresistant cell lines, and patient-derived tumoroid models. Additionally, blocking these genes improved 5-FU sensitivity in chemoresistant CRC cells. Our findings propose a new claudin-based molecular signature that associates with poor prognosis as well as characteristics of treatment-resistant CRC including chemoresistance, metastasis, and relapse.

TF-RBP-AS Triplet Analysis Reveals the Mechanisms of Aberrant Alternative Splicing Events in Kidney Cancer: Implications for Their Possible Clinical Use as Prognostic and Therapeutic Biomarkers

Aberrant alternative splicing (AS) is increasingly linked to cancer; however, how AS contributes to cancer development still remains largely unknown. AS events (ASEs) are largely regulated by RNA-binding proteins (RBPs) whose ability can be modulated by a variety of genetic and epigenetic mechanisms. In this study, we used a computational framework to investigate the roles of transcription factors (TFs) on regulating RBP-AS interactions. A total of 6519 TF–RBP–AS triplets were identified, including 290 TFs, 175 RBPs, and 16 ASEs from TCGA–KIRC RNA sequencing data. TF function categories were defined according to correlation changes between RBP expression and their targeted ASEs. The results suggested that most TFs affected multiple targets, and six different classes of TF-mediated transcriptional dysregulations were identified. Then, regulatory networks were constructed for TF–RBP–AS triplets. Further pathway-enrichment analysis showed that these TFs and RBPs involved in triplets were enriched in a variety of pathways that were associated with cancer development and progression. Survival analysis showed that some triplets were highly associated with survival rates. These findings demonstrated that the integration of TFs into alternative splicing regulatory networks can help us in understanding the roles of alternative splicing in cancer.

TMEM100 negatively regulated by microRNA‑106b facilitates cellular apoptosis by suppressing survivin expression in NSCLC

Non‑small cell lung cancer (NSCLC) is a common malignant tumour. Nevertheless, the 5‑year survival rate of NSCLC patients remains poor. Thus, identifying critical factors involved in regulating the progression of NSCLC is important for providing potential treatment targets. In the present study, it was observed that transmembrane protein 100 (TMEM100) was significantly downregulated in NSCLC tissues compared with paired peritumoral tissues. Decreased TMEM100 expression was associated with poor clinical outcomes in NSCLC patients. Moreover, TMEM100 overexpression inhibited colony formation and facilitated apoptosis by suppressing survivin expression in NSCLC cells, whereas TMEM100 knockdown had the opposite effect. In addition, microRNA (miR)‑106b, a miR with controversial roles in different human cancers, was upregulated in NSCLC and directly downregulated TMEM100 expression. The roles of miR‑106b in cell survival were mitigated by the restoration of TMEM100. The aforementioned results indicated that TMEM100 induced cell apoptosis and inhibited cell survival by serving as a tumour suppressor and that miR‑106b‑mitigatedTMEM100 expression defined a potentially oncogenic pathway in NSCLC.

Biallelic variants in TMEM222 cause a new autosomal recessive neurodevelopmental disorder

PURPOSE

To elucidate the novel molecular cause in families with a new autosomal recessive neurodevelopmental disorder.

METHODS

A combination of exome sequencing and gene matching tools was used to identify pathogenic variants in 17 individuals. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) and subcellular localization studies were used to characterize gene expression profile and localization.

RESULTS

Biallelic variants in the TMEM222 gene were identified in 17 individuals from nine unrelated families, presenting with intellectual disability and variable other features, such as aggressive behavior, shy character, body tremors, decreased muscle mass in the lower extremities, and mild hypotonia. We found relatively high TMEM222 expression levels in the human brain, especially in the parietal and occipital cortex. Additionally, subcellular localization analysis in human neurons derived from induced pluripotent stem cells (iPSCs) revealed that TMEM222 localizes to early endosomes in the synapses of mature iPSC-derived neurons.

CONCLUSION

Our findings support a role for TMEM222 in brain development and function and adds variants in the gene TMEM222 as a novel underlying cause of an autosomal recessive neurodevelopmental disorder.

TMEM45A Affects Proliferation, Apoptosis, Epithelial-Mesenchymal Transition, Migration, Invasion and Cisplatin Resistance of HPV-Positive Cervical Cancer Cell Lines

To investigate the effects of transmembrane protein 45A (TMEM45A) on biological characteristics and cisplatin (DDP) resistance of cervical cancer cells. TMEM45A in cervical cancer cells and normal cervical epithelial cells (HCerEpiC) were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. HPV genotypes were identified by multiplex PCR. SiHa and HeLa cells were divided into Blank, shCTL, shTMEM45A-1, and shTMEM45A-2 groups, followed by Cell Counting Kit-8 (CCK-8), EdU, Annexin V-FITC/PI staining, Wound healing, and Transwell invasion assays, as well as qRT-PCR and Western blotting. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) was employed to evaluate the impact of TMEM45A shRNA on cisplatin-resistant cervical cancer cells (SiHa/DDP and HeLa/DDP). Compared with HcerEpic cell, cervical cancer cells exhibited the upregulation of TMEM45A expression, especially in HPV-positive cell lines (CaSki, SiHa, HeLa). TMEM45A shRNA suppressed the proliferation of SiHa and HeLa cells, arrested cells at the S phase, and promoted cell apoptosis. TMEM45A shRNA inhibited the epithelial-mesenchymal transition (EMT), invasion, migration of SiHa and HeLa cells, accompanying by the downregulated Vimentin and N-cadherin with the upregulated E-cadherin. Moreover, SiHa/DDP and HeLa/DDP had higher TMEM45A expression than their parental SiHa and HeLa cells, respectively. And inhibiting TMEM45A can reduce the IC50 of SiHa/DDP cells and HeLa/DDP cells to cisplatin. Silencing TMEM45A can inhibit cell proliferation, invasion, migration and EMT, regulate cell cycle distribution, promote cell apoptosis, and reverse cisplatin resistance of HPV-positive cervical cancer cells, highlighting that inhibition of TMEM45A may be a therapeutic strategy for HPV-positive cervical cancer.

Methylation of three genes encoded by X chromosome in blood leukocytes and colorectal cancer risk

X chromosome change has been proved to be associated with carcinogenesis and related to gender differences in cancer risk. If aberrant methylation of genes encoded by X chromosome involve in the risk and prognosis of cancers, including colorectal cancer (CRC), remain unclear. We conducted a case–control study consisted of 432 CRC cases and 434 controls, detecting the methylation levels of FAM156B, PIH1D3, and PPP1R3F in the X chromosome in blood leukocytes using methylation‐sensitive high‐resolution melting (MS‐HRM). We analyzed the relationship between the methylation levels and CRC susceptibility and then explored the interactions with environmental factors on CRC risk with logistics regression. Moreover, we conducted a follow‐up study containing 225 CRC patients to explore the associations between the methylation of FAM156B, PPP1R3F, and PIH1D3 and CRC prognosis. The hypermethylation of FAM156B, PPP1R3F, and PIH1D3 was related to increased CRC risk (OR_PS‐adj = 2.932, 95% confidence interval [CI]: 2.029–4.237; OR_PS‐adj = 1.602, 95% CI: 1.078–2.382; OR_PS‐adj = 1.628, 95% CI: 1.065–2.490, respectively). In the multiple CpG site methylation (MCSM) analysis, compared with non‐MCSM, a significant relationship between MCSM and increased CRC risk was found (OR_PS‐adj = 2.202, 95% CI: 1.512–3.208). We observed synergistic interaction between PPP1R3F hypermethylation and fried food consumption on CRC risk (OR_i = 2.682, 95% CI: 1.321–5.446). However, there were no associations between the methylation of FAM156B, PPP1R3F, and PIH1D3 and CRC prognosis (p > 0.05). In conclusion, the methylation of FAM156B, PPP1R3F, and PIH1D3 genes in blood leukocytes is significantly related to CRC risk and may be potential biomarkers for CRC risk but not prognosis.

Membrane protein regulators of melanoma pulmonary colonisation identified using a CRISPRa screen and spontaneous metastasis assay in mice

Metastasis is the spread of cancer cells to a secondary site within the body, and is the leading cause of death for cancer patients. The lung is a common site of metastasis for many cancer types, including melanoma. Identifying the genes involved in aiding metastasis of melanoma cells to the lungs is critical for the development of better treatments. As the accessibility of cell surface proteins makes them attractive therapeutic targets, we performed a CRISPR activation screen using a library of guide RNAs (gRNAs) targeting the transcription start sites of 2195 membrane protein-encoding genes, to identify genes whose upregulated expression aided pulmonary metastasis. Immunodeficient mice were subcutaneously injected in the flank with murine B16-F0 melanoma cells expressing dCas9 and the membrane protein library gRNAs, and their lungs collected after 14–21 days. Analysis was performed to identify the gRNAs that were enriched in the lungs relative to those present in the cells at the time of administration (day 0). We identified six genes whose increased expression promotes lung metastasis. These genes included several with well-characterized pro-metastatic roles (Fut7, Mgat5, and Pcdh7) that have not previously been linked to melanoma progression, genes linked to tumor progression but that have not previously been described as involved in metastasis (Olfr322 and Olfr441), as well as novel genes (Tmem116). Thus, we have identified genes that, when upregulated in melanoma cells, can aid successful metastasis and colonization of the lung, and therefore may represent novel therapeutic targets to inhibit pulmonary metastasis.

Exploration of novel candidate genes involved in epidermal keratinocyte differentiation and skin barrier repair in man

A proper skin barrier function requires constant formation of stratum corneum, i.e. the outermost layer of epidermis composed of terminally differentiated keratinocytes. The complex process of converting proliferative basal keratinocytes into corneocytes relies on programmed changes in the activity of many well-established genes. Much remains however to be investigated about this process, e.g. in conjunction with epidermal barrier defects due to genetic errors as in ichthyosis. To this end, we re-analyzed two sets of microarray-data comparing altered gene expression in differentiated vs. proliferating keratinocytes and in the skin of patients with autosomal recessive congenital ichthyosis (ARCI) vs. healthy controls, respectively. We thus identified 24 genes to be upregulated in both sets of array and not previously associated with keratinocyte differentiation. For 10 of these genes (AKR1B10, BLNK, ENDOU, GCNT4, GLTP, RHCG, SLC15A1, TMEM45B, TMEM86A and VSNL1), qPCR analysis confirmed the array results and subsequent immunostainings of normal epidermis showed superficial expression of several of the proteins. Furthermore, induction of keratinocyte differentiation using phorbol esters (PMA) resulted in increased expression of eight of the genes, whereas siRNA silencing of PPARδ, a transcription factor supporting differentiation, had the opposite effect. In summary, our results identify ten new candidate genes seemingly involved in human epidermal keratinocyte differentiation and possibly important for epidermal repair in a genetic skin disease characterized by barrier failure.

Review of Prognostic Expression Markers for Clear Cell Renal Cell Carcinoma

Context: The number of prognostic markers for clear cell renal cell carcinoma (ccRCC) has been increasing regularly over the last 15 years, without being integrated and compared. Objective: Our goal was to perform a review of prognostic markers for ccRCC to lay the ground for their use in the clinics. Evidence Acquisition: PubMed database was searched to identify RNA and protein markers whose expression level was reported as associated with survival of ccRCC patients. Relevant studies were selected through cross-reading by two readers. Evidence Synthesis: We selected 249 studies reporting an association with prognostic of either single markers or multiple-marker models. Altogether, these studies were based on a total of 341 distinct markers and 13 multiple-marker models. Twenty percent of these markers were involved in four biological pathways altered in ccRCC: cell cycle, angiogenesis, hypoxia, and immune response. The main genes (VHL, PBRM1, BAP1, and SETD2) involved in ccRCC carcinogenesis are not the most relevant for assessing survival. Conclusion: Among single markers, the most validated markers were KI67, BIRC5, TP53, CXCR4, and CA9. Of the multiple-marker models, the most famous model, ClearCode34, has been highly validated on several independent datasets, but its clinical utility has not yet been investigated. Patient Summary: Over the years, the prognosis studies have evolved from single markers to multiple-marker models. Our review highlights the highly validated prognostic markers and multiple-marker models and discusses their clinical utility for better therapeutic care.

Overexpression of TMEM47 Induces Tamoxifen Resistance in Human Breast Cancer Cells

Background:

Tamoxifen (TAM) is the eminent first-line drug for endocrine therapy of hormone receptor positive premenopausal breast cancer and reduces the risk of recurrence by ∼50%. However, many patients developed TAM resistance and their diseases recurred. Our previous study on transcriptome profile of TAM resistant breast cancer cells revealed that the TMEM47 is one of the most significantly differentially expressed genes. The mechanism of how TMEM47 is involved in TAM resistance was not known.

Methods:

We constructed a mammal breast cancer cell line, in which TMEM47 was stably overexpressed (TMEM47-OE/MCF-7), to further verify the role of TMEM47 in TAM resistance. siRNA targeting TMEM47 was transfected into TAMR / MCF-7 cells by Liposome. TMEM47 expression was validated on mRNA and protein level by qRT-PCR and western blotting. We tested the cytotoxicity of TAM in the cells. Apoptosis was detected by flow cytometry.

Results:

Compared to the MCF7 cells, TMEM47 mRNA was significantly up regulated more than 6 folds in the TAMR/MCF7 cells and so its protein. TMEM47 expression level in TMEM47-OE/MCF-7 was similar as in the TAMR/MCF-7 cells. The 50% inhibitory concentration (IC50) value (mean ± SD) of TAM in MCF-7, TAMR/MCF-7 and TMEM47-OE/MCF-7 cells was 1.58 ± 0.19, 2.74 ± 0.24 and 3.12 ± 0.32 µγ/mL, respectively. The apoptosis rates of TAMR/MCF-7 and TMEM47-OE/MCF-7 cell lines were significantly lower than that of MCF-7 cells. After 24 and 48 hours TAM treatments, cell viability was significantly inhibitied in TMEM47 knockdown TAMR/MCF7 cells (P < 0.01). Consistant with the decreased cell viability, the apoptosis rate in TMEM47 knockdown TAMR/MCF-7 cells was significantly increased.

Conclusions:

Our results suggest that overexpression of TMEM47 in MCF-7 cells acquired TAM resistance to those cells, and knockdown of TMEM47 in TAMR/MCF-7 cells reversed their resistance to TAM. TMEM47 might confer TAM resistance on MCF-7 cells through the inhibition of apoptosis.

New Insights Into Oral Squamous Cell Carcinoma: From Clinical Aspects to Molecular Tumorigenesis

Oral squamous cell carcinoma (SCC) is a prevalent malignant disease worldwide, especially so in Taiwan. Early- or even preclinical-stage detection is critical for reducing morbidity and mortality from oral SCC. Epidemiological and genome association studies are useful for identifying clinicopathological risk factors for preventive, diagnostic, and therapeutic approaches of oral SCC. For advanced oral SCC, effective treatments are critical to prolonging survival and enhancing quality of life. As oral SCC is characteristic of regional invasion with lymph node metastases, understanding the aggressive features of oral SCC, particularly in lymphangiogenesis, is essential for determining effective treatments. Emerging evidence has demonstrated that the tumor microenvironment (TME) plays a pivotal role in tumor growth, invasion, and metastases. Recent clinical successes in immune checkpoint inhibitors either alone or combined with chemotherapy have also supported the therapeutic value of immunotherapy in oral SCC. This review summarizes critical advances in basic knowledge of oral SCC from the perspective of clinicopathological risk factors, molecular tumorigenesis, and the TME. We also highlight our recent investigations on the microbiome, genome association studies, lymphangiogenesis, and immunomodulation in oral SCC. This review may provide new insights for oral SCC treatment by systematically interpreting emerging evidence from various preclinical and clinical studies.

TMEM106C contributes to the malignant characteristics and poor prognosis of hepatocellular carcinoma

Transmembrane protein (TMEM) is a kind of integral membrane protein that spans biological membranes. The functions of most members of the TMEM family are unknown. Here, we conducted bioinformatic analysis and biological validation to investigate the role of TMEM106C in HCC. First, GEPIA and Oncomine^TM were used to analyze TMEM106C expression, which was verified by real-time PCR and western blot analyses. Then, the biological functions of TMEM106C were explored by CCK8 and transwell assays. The prognostic value of TMEM106C was analyzed by UALCAN. LinkedOmics was used to analyze TMEM106C pathways generated by Gene Ontology. A protein-protein interaction network (PPI) was constructed by GeneMANIA. We demonstrated that TMEM106C was overexpressed in HCC and that inhibition of TMEM106C significantly suppressed the proliferation and metastasis of HCC through targeting CENPM and DLC-1. Upregulation of TMEM106C was closely correlated with sex, tumor stage, tumor grade and prognosis. Overexpression of TMEM106C was linked to functional networks involving organelle fission and cell cycle signaling pathways through the regulation of CDK kinases, E2F1 transcription factors and miRNAs. Our data demonstrated that TMEM106C contributes to malignant characteristics and poor prognosis in HCC, which may serve as a prognostic biomarker and potential therapeutic target.

Upregulation of TMEM45A Promoted the Progression of Clear Cell Renal Cell Carcinoma in vitro

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is the most common and aggressive type of primary kidney cancer worldwide. Transmembrane protein 45A (TMEM45A) has been reported to be closely associated with the progression of several cancers. However, the role of TMEM45A in ccRCC remains unclear. Our study intended to explore the potential role of TMEM45A in ccRCC.

METHODS

Data on the expression of TMEM45A were obtained from multiple databases, including UCSC, GEPIA2, Oncomine and TIMER. Real-world samples of ccRCC and paired normal renal tissues were used to confirm the information obtained from the databases. In addition, the prognostic value of TMEM45A was evaluated. Loss-of-function assays were performed using TMEM45A-targeting lentivirus to evaluate the biological role of TMEM45A in renal cancer cells. Gene set enrichment analysis (GSEA) was performed to investigate the potential molecular mechanisms.

RESULTS

TMEM45A was significantly overexpressed in patients with ccRCC and correlated with poor overall survival and disease-free survival. In addition, the expression of TMEM45A was closely associated with various clinicopathological parameters such as histological grade and TNM stage. Knockdown of TMEM45A inhibited the proliferation and migration and promoted the apoptosis of ccRCC cells in vitro. The results of the GSEA suggested that TMEM45A was potentially involved in the promotion of epithelial-mesenchymal transition (EMT) and inflammatory response in ccRCC.

CONCLUSION

TMEM45A was overexpressed and associated with poor survival and acted as a tumour promoter in ccRCC; therefore, might be a potential prognostic marker and therapeutic target.

Mutation analysis of TMEM family members for early-onset Parkinson's disease in Chinese population

Members of the transmembrane (TMEM) protein family have been identified to be associated with Parkinson's disease (PD) and other neurodegenerative disorders. However, most studies were based on the European-ancestry population and were still awaiting replications. Here, we aimed to systematically evaluate the associations of TMEMs with PD in a large Chinese early-onset PD (EOPD, age at onset <50 years) cohort. We identified rare variants (minor allele frequency <0.01) in 743 unrelated EOPD patients using whole-exome sequencing and evaluated the association between variants and EOPD at allele and gene levels. Totally 45 rare variants were identified in 6 TMEM protein family members. At allele level, p.176 K>E in TMEM175 and p.33P>R in TMEM163 were significantly associated with PD. Gene-based burden analysis showed a clear enrichment of TMEM163 variants in EOPD. Our work identifies 2 novel rare variants and TMEM163 as potential risk factors for PD provide a better understanding of the genetic involvement of TMEM protein family members in EOPD and broadens the current mutation spectrum of PD.

Transcriptome alterations in HepG2 cells induced by shRNA knockdown and overexpression of TMEM2 gene

Transmembrane 2 (TMEM2) gene inhibits chronic hepatitis-B virus (HBV) infection, while the underlying molecular mechanisms remain unknown. Transcriptome alterations in HepG2 cells following TMEM2 overexpression or silencing by shRNA were analyzed by next-generation sequencing. Both overexpression and knockdown of the TMEM2 gene caused wide-spread changes in gene expression in HepG2 cells. Differentially expressed genes caused by altered TMEM2 gene expression were associated with multiple biological processes linked with viral infection and various signaling pathways. KEGG analysis revealed that many of the differentially expressed genes were enriched in the PI3K/AKT signaling pathway. Moreover, we show that genes related to the PI3K/AKT signaling pathway, such as SYK, FLT4, AKT3, FLT1, and IL6, are biological targets regulated by TMEM2 in HepG2 cells. This is the first transcriptome-wide study in which TMEM2-regulated genes in HepG2 cells have been screened. Our findings elucidate the molecular events associated with TMEM2-mediated hepatocyte pathogenesis in chronic HBV infection.

Dynamic Alternative Splicing During Mouse Preimplantation Embryo Development

The mechanism of alternative pre-mRNA splicing (AS) during preimplantation development is largely unknown. In order to capture the dynamic changes of AS occurring during embryogenesis, we carried out bioinformatics analysis based on scRNA-seq data over the time-course preimplantation development in mouse. We detected numerous previously-unreported differentially expressed genes at specific developmental stages and investigated the nature of AS at both minor and major zygotic genome activation (ZGA). The AS and differential AS atlas over preimplantation development were established. The differentially alternatively spliced genes (DASGs) are likely to be key splicing factors (SFs) during preimplantation development. We also demonstrated that there is a regulatory cascade of AS events in which some key SFs are regulated by differentially AS of their own gene transcripts. Moreover, 212 isoform switches (ISs) during preimplantation development were detected, which may be critical for decoding the mechanism of early embryogenesis. Importantly, we uncovered that zygotic AS activation (ZASA) is in conformity with ZGA and revealed that AS is coupled with transcription during preimplantation development. Our results may provide a deeper insight into the regulation of early embryogenesis.

The comparative biochemistry of viruses and humans: an evolutionary path towards autoimmunity

Analyses of the peptide sharing between five common human viruses (Borna disease virus, influenza A virus, measles virus, mumps virus and rubella virus) and the human proteome highlight a massive viral vs. human peptide overlap that is mathematically unexpected. Evolutionarily, the data underscore a strict relationship between viruses and the origin of eukaryotic cells. Indeed, according to the viral eukaryogenesis hypothesis and in light of the endosymbiotic theory, the first eukaryotic cell (our lineage) originated as a consortium consisting of an archaeal ancestor of the eukaryotic cytoplasm, a bacterial ancestor of the mitochondria and a viral ancestor of the nucleus. From a pathologic point of view, the peptide sequence similarity between viruses and humans may provide a molecular platform for autoimmune crossreactions during immune responses following viral infections/immunizations.