Transmembrane emp24 domain proteins in development and disease

The endoplasmic reticulum as a cradle for virus and extracellular vesicle secretion

Extracellular vesicles (EVs) are small membranous carriers of protein, lipid, and nucleic acid cargoes and play a key role in intercellular communication. Recent work has revealed the previously under-recognized participation of endoplasmic reticulum (ER)-associated proteins (ERAPs) during EV secretion, using pathways reminiscent of viral replication and secretion. Here, we present highlights of the literature involving ER/ERAPs in EV biogenesis and propose mechanistic parallels with ERAPs exploited during viral infections. We propose that ERAPs play an active role in the release of EVs and viral particles, and we present views on whether viruses hijack or enhance pre-existing ERAP-dependent secretory machineries or whether they repurpose ERAPs to create new secretory pathways.

Disrupted uromodulin trafficking is rescued by targeting TMED cargo receptors

The trafficking dynamics of uromodulin (UMOD), the most abundant protein in human urine, play a critical role in the pathogenesis of kidney disease. Monoallelic mutations in the UMOD gene cause autosomal dominant tubulointerstitial kidney disease (ADTKD-UMOD), an incurable genetic disorder that leads to kidney failure. The disease is caused by the intracellular entrapment of mutant UMOD in kidney epithelial cells, but the precise mechanisms mediating disrupted UMOD trafficking remain elusive. Here, we report that transmembrane Emp24 protein transport domain-containing (TMED) cargo receptors TMED2, TMED9, and TMED10 bind UMOD and regulate its trafficking along the secretory pathway. Pharmacological targeting of TMEDs in cells, in human kidney organoids derived from patients with ADTKD-UMOD, and in mutant-UMOD-knockin mice reduced intracellular accumulation of mutant UMOD and restored trafficking and localization of UMOD to the apical plasma membrane. In vivo, the TMED-targeted small molecule also mitigated ER stress and markers of kidney damage and fibrosis. Our work reveals TMED-targeting small molecules as a promising therapeutic strategy for kidney proteinopathies.

Choroid plexus extracellular vesicle transport of blood-borne insulin-like growth factor 1 to the hippocampus of the immature brain

Reduced serum level of insulin-like growth factor 1 (IGF-1), a major regulator of perinatal development, in extremely preterm infants has been shown to be associated with neurodevelopmental impairment. To clarify the mechanism of IGF-1 transport at the blood-cerebrospinal fluid (CSF) barrier of the immature brain, we combined studies of in vivo preterm piglet and rabbit models with an in vitro transwell cell culture model of neonatal primary murine choroid plexus epithelial (ChPE) cells. We identified IGF-1-positive intracellular vesicles in ChPE cells and provided data indicating a directional transport of IGF-1 from the basolateral to the apical media in extracellular vesicles (EVs). Exposure of the ChPE cells to human IGF-1 on the basolateral side increased the secretion of IGF-1-positive EVs in the apical media. Mass spectrometry analysis displayed similarities in protein content between EVs derived from preterm piglet CSF-derived and ChPE cell-derived EVs. Furthermore, exposure of ChPE cells to human IGF-1 caused an enrichment of human IGF-1 and transmembrane p24 trafficking protein 2, proteins important for perinatal development, in apical media-derived EVs. Moreover, intraventricular injections of ChPE cell-derived EVs in preterm rabbit pups resulted in an uptake of EVs in the brain, displaying penetration through the ependymal lining and deep into the hippocampus. Finally, exposure of rat hippocampus neurons to ChPE cell-derived EVs resulted in internalization of the EVs in hippocampal soma and neurites. In summary, we describe a transport pathway for blood-borne IGF-1 in EVs through the blood-CSF barrier to the hippocampus in the immature brain.

TMED inhibition suppresses cell surface PD-1 expression and overcomes T cell dysfunction

BACKGROUND

Blockade of the programmed cell death protein 1 (PD-1) immune checkpoint (ICB) is revolutionizing cancer therapy, but little is known about the mechanisms governing its expression on CD8 T cells. Because PD-1 is induced during activation of T cells, we set out to uncover regulators whose inhibition suppresses PD-1 abundance without adversely impacting on T cell activation.

METHODS

To identify PD-1 regulators in an unbiased fashion, we performed a whole-genome, fluorescence-activated cell sorting (FACS)-based CRISPR-Cas9 screen in primary murine CD8 T cells. A dual-readout design using the activation marker CD137 allowed us to uncouple genes involved in PD-1 regulation from those governing general T cell activation.

RESULTS

We found that the inactivation of one of several members of the TMED/EMP24/GP25L/p24 family of transport proteins, most prominently TMED10, reduced PD-1 cell surface abundance, thereby augmenting T cell activity. Another client protein was cytotoxic T lymphocyte-associated protein 4 (CTLA-4), which was also suppressed by TMED inactivation. Treatment with TMED inhibitor AGN192403 led to lysosomal degradation of the TMED-PD-1 complex and reduced PD-1 abundance in tumor-infiltrating CD8 T cells (TIL) in mice, thus reversing T cell dysfunction. Clinically corroborating these findings, single-cell RNA analyses revealed a positive correlation between TMED expression in CD8 TIL, and both a T cell dysfunction signature and lack of ICB response. Similarly, patients receiving a TIL product with high TMED expression had a shorter overall survival.

CONCLUSION

Our results uncover a novel mechanism of PD-1 regulation, and identify a pharmacologically tractable target whose inhibition suppresses PD-1 abundance and T cell dysfunction.

A systematic review on the selection of reference genes for gene expression studies in rodents: are the classics the best choice?

Rodents are commonly used as animal models in studies investigating various experimental conditions, often requiring gene expression analysis. Quantitative real-time reverse transcription PCR (RT-qPCR) is the most widely used tool to quantify target gene expression levels under different experimental conditions in various biological samples. Relative normalization with reference genes is a crucial step in RT-qPCR to obtain reliable quantification results. In this work, the main reference genes used in gene expression studies among the three rodents commonly employed in scientific research-hamster, rat, and mouse-are analyzed and described. An individual literature search for each rodent was conducted using specific search terms in three databases: PubMed, Scopus, and Web of Science. A total of 157 articles were selected (rats = 73, mice = 79, and hamsters = 5), identifying various reference genes. The most commonly used reference genes were analyzed according to each rodent, sample type, and experimental condition evaluated, revealing a great variability in the stability of each gene across different samples and conditions. Classic genes, which are expected to be stably expressed in both samples and conditions analyzed, demonstrated greater variability, corroborating existing concerns about the use of these genes. Therefore, this review provides important insights for researchers seeking to identify suitable reference genes for their validation studies in rodents.

The Role of Cornichons in the Biogenesis and Functioning of Monovalent-Cation Transport Systems

Monovalent-cation homeostasis, crucial for all living cells, is ensured by the activity of various types of ion transport systems located either in the plasma membrane or in the membranes of organelles. A key prerequisite for the functioning of ion-transporting proteins is their proper trafficking to the target membrane. The cornichon family of COPII cargo receptors is highly conserved in eukaryotic cells. By simultaneously binding their cargoes and a COPII-coat subunit, cornichons promote the incorporation of cargo proteins into the COPII vesicles and, consequently, the efficient trafficking of cargoes via the secretory pathway. In this review, we summarize current knowledge about cornichon proteins (CNIH/Erv14), with an emphasis on yeast and mammalian cornichons and their role in monovalent-cation homeostasis. Saccharomyces cerevisiae cornichon Erv14 serves as a cargo receptor of a large portion of plasma-membrane proteins, including several monovalent-cation transporters. By promoting the proper targeting of at least three housekeeping ion transport systems, Na+, K+/H+ antiporter Nha1, K+ importer Trk1 and K+ channel Tok1, Erv14 appears to play a complex role in the maintenance of alkali-metal-cation homeostasis. Despite their connection to serious human diseases, the repertoire of identified cargoes of mammalian cornichons is much more limited. The majority of current information is about the structure and functioning of CNIH2 and CNIH3 as auxiliary subunits of AMPAR multi-protein complexes. Based on their unique properties and easy genetic manipulation, we propose yeast cells to be a useful tool for uncovering a broader spectrum of human cornichons´ cargoes.

The journey of STING: Guiding immune signaling through membrane trafficking

Stimulator of Interferon Genes (STING) serves as a pivotal mediator in the innate immune signaling pathway, transducing signals from various DNA receptors and playing a crucial role in natural immune processes. During cellular quiescence, STING protein resides in the endoplasmic reticulum (ER), and its activation typically occurs through the cGAS-STING signaling pathway. Upon activation, STING protein is transported to the Golgi apparatus, thereby initiating downstream signaling cascades. Vesicular transport serves as the primary mechanism for STING protein trafficking between the ER and Golgi apparatus, with COPII mediating anterograde transport from the ER to Golgi apparatus, while COPI is responsible for retrograde transport. Numerous factors influence these transport processes, thereby exerting either promoting or inhibitory effects on STING protein expression. Upon reaching the Golgi apparatus, to prevent over-activation, STING protein is transported to post-Golgi compartments for degradation. In addition to the conventional lysosomal degradation pathway, ESCRT has also been identified as one of the degradation pathways for STING protein. This review summarizes the recent findings on the membrane trafficking pathways of STING, highlighting their contributions to the regulation of cytokine production, the activation of immune cells, and the coordination of immune signaling pathways.

Protein Dynamic Landscape during Mouse Mammary Gland Development from Virgin to Pregnant, Lactating, and Involuting Stages

The mammary gland undergoes significant physiological changes as it undergoes a transition from virgin to pregnancy, lactation, and involution. However, the dynamic role of proteins in regulating these processes during mouse mammary gland development has not been thoroughly explored. In this study, we collected mouse mammary gland tissues from mature virgins aged 8-10 weeks (V), day 16 of pregnancy (P16d), day 12 of lactation (L12d), day 1 of forced weaning (FW 1d), and day 3 of forced weaning (FW 3d) stages for analysis using DIA-based quantitative proteomics technology. A total of 3,312 proteins were identified, of which 843 were DAPs that were categorized into nine clusters based on their abundance changes across developmental stages. Notably, DAPs in cluster 2, which peaked at the L12d stage, were primarily associated with mammary gland development and lactation. The protein-protein interaction network revealed that the epidermal growth factor (EGF) was central to this cluster. Our study provides a comprehensive overview of the mouse mammary gland development proteome and identifies some important proteins, such as EGF, Janus kinase 1 (JAK1), and signal transducer and activator of transcription 6 (STAT6) that may serve as potential targets for future research to provide guidelines for a deeper understanding of the developmental biology of mammary glands.

Development of a breast cancer prognostic model based on vesicle-mediated transport-related genes to predict immune landscape and clinical drug therapy

BACKGROUND

Vesicle-mediated transport, vital for substance exchange and intercellular communication, is linked to tumor initiation and progression. This work was designed to study the role of vesicle-mediated transport-related genes (VMTRGs) in breast cancer (BC)prognosis.

METHODS

Univariate Cox analysis was utilized to screen prognosis-related VMTRGs. BC samples underwent unsupervised clustering based on VMTRGs to analyze survival, clinical factors, and immune cell abundance across different subtypes. We constructed a risk model using univariate Cox and LASSO regression analysis, with validation conducted using GEO datasets. Subsequently, we performed tumor mutational burden analysis, and immune landscape analysis on both groups. Ultimately, we conducted immunophenoscore (IPS) scoring to forecast immunotherapy and performed drug sensitivity analysis.

RESULTS

We identified 102 VMTRGs associated with BC prognosis. Using these 102 VMTRGs, BC patients were classified into 3 subtypes, with Cluster3 patients showing significantly better survival rates. We constructed a prognostic model for BC based on 12 VMTRGs that effectively predicted patient survival. Riskscore was an independent prognostic factor for BC patients. According to median risk score, high-risk group (HRG) had higher TMB values. The immune landscape of the HRG exhibited characteristics of cold tumor, with higher immune checkpoint expression levels and lower IPS scores, whereas Gemcitabine, Nilotinib, and Oxaliplatin were more suitable for treating low-risk group.

CONCLUSION

We classified BC subtypes and built a prognostic model based on VMTRGs. The genes in the prognostic model may serve as potential targets for BC therapy.

RHBDL4-triggered downregulation of COPII adaptor protein TMED7 suppresses TLR4-mediated inflammatory signaling

The toll-like receptor 4 (TLR4) is a central regulator of innate immunity that primarily recognizes bacterial lipopolysaccharide cell wall constituents to trigger cytokine secretion. We identify the intramembrane protease RHBDL4 as a negative regulator of TLR4 signaling. We show that RHBDL4 triggers degradation of TLR4's trafficking factor TMED7. This counteracts TLR4 transport to the cell surface. Notably, TLR4 activation mediates transcriptional upregulation of RHBDL4 thereby inducing a negative feedback loop to reduce TLR4 trafficking to the plasma membrane. This secretory cargo tuning mechanism prevents the over-activation of TLR4-dependent signaling in an in vitro Mycobacterium tuberculosis macrophage infection model and consequently alleviates septic shock in a mouse model. A hypomorphic RHBDL4 mutation linked to Kawasaki syndrome, an ill-defined inflammatory disorder in children, further supports the pathophysiological relevance of our findings. In this work, we identify an RHBDL4-mediated axis that acts as a rheostat to prevent over-activation of the TLR4 pathway.

TMED2 promotes glioma tumorigenesis by being involved in EGFR recycling transport

Aberrant epidermal growth factor receptor (EGFR) signaling is the core signaling commonly activated in glioma. The transmembrane emp24 protein transport domain protein 2 (TMED2) interacts with cargo proteins involved in protein sorting and transport between endoplasmic reticulum (ER) and Golgi apparatus. In this study, we found the correlation between TMED2 with glioma progression and EGFR signaling through database analysis. Moreover, we demonstrated that TMED2 is essential for glioma cell proliferation, migration, and invasion at the cellular levels, as well as tumor formation in mouse models, underscoring its significance in the pathobiology of gliomas. Mechanistically, TMED2 was found to enhance EGFR-AKT signaling by facilitating EGFR recycling, thereby providing the initial evidence of TMED2's involvement in the membrane protein recycling process. In summary, our findings shed light on the roles and underlying mechanisms of TMED2 in the regulation of glioma tumorigenesis and EGFR signaling, suggesting that targeting TMED2 could emerge as a promising therapeutic strategy for gliomas and other tumors associated with aberrant EGFR signaling.

The Role of BmTMED6 in Female Reproduction in Silkworm, Bombyx mori

Transmembrane emp24 domain (TMED) proteins have been extensively studied in mammalian embryonic development, immune regulation, and signal transduction. However, their role in insects, apart from Drosophila melanogaster, remains largely unexplored. Our previous study demonstrated the abundant expression of BmTMED6 across all stages and tissues of the silkworm. In this study, we investigate the function of BmTMED6 in reproduction. We observe significant differences in the expression of BmTMED6 between male and female silkworms, particularly in the head and fatboby, during the larval stage. Furthermore, qRT-PCR and WB analysis reveal substantial variation in BmTMED6 levels in the ovaries during pupal development, suggesting a potential association with silkworm female reproduction. We find that reducing TMED6 expression significantly decreases the number of eggs laid by female moths, leading to an accumulation of unlaid eggs in the abdomen. Moreover, downregulation of BmTMED6 leads to a decrease in the expression of BmDop2R1 and BmDop2R2, while overexpression of BmTMED6 in vitro has the opposite effect. These indicate that BmTMED6 plays a role in oviposition in female moths, potentially through the dopamine signaling pathway. This study provides a new regulatory mechanism for female reproduction in insects.

Integrative Multi-Omics Analysis Identifies Transmembrane p24 Trafficking Protein 1 (TMED1) as a Potential Prognostic Marker in Colorectal Cancer

Several TMED protein family members are overexpressed in malignant tumors and associated with tumor progression. TMED1 belongs to the TMED protein family and is involved in protein vesicular trafficking. However, the expression level and biological role of TMED1 in colorectal cancer (CRC) have yet to be fully elucidated. In this study, the integration of patient survival and multi-omics data (immunohistochemical staining, transcriptomics, and proteomics) revealed that the highly expressed TMED1 was related to the poor prognosis in CRC. Crystal violet staining indicated the cell growth was reduced after knocking down TMED1. Moreover, the flow cytometry results showed that TMED1 knockdown could increase cell apoptosis. The expression of TMED1 was positively correlated with other TMED family members (TMED2, TMED4, TMED9, and TMED10) in CRC, and the protein-protein interaction network suggested its potential impact on immune regulation. Furthermore, TMED1 expression was positively associated with the infiltration levels of regulatory T cells (Tregs), cancer-associated fibroblasts (CAFs), and endothelial cells and negatively correlated with the infiltration levels of CD4+ T cells, CD8+ T cells, and B cells. At last, the CTRP and GDSC datasets on the GSCA platform were used to analyze the relationship between TMED1 expression and drug sensitivity (IC50). The result found that the elevation of TMED1 was positively correlated with IC50 and implied it could increase the drug resistance of cancer cells. This research revealed that TMED1 is a novel prognostic biomarker in CRC and provided a valuable strategy for analyzing potential therapeutic targets of malignant tumors.

TMED10 mediates the trafficking of insulin-like growth factor 2 along the secretory pathway for myoblast differentiation

The insulin-like growth factor 2 (IGF2) plays critical roles in cell proliferation, migration, differentiation, and survival. Despite its importance, the molecular mechanisms mediating the trafficking of IGF2 along the secretory pathway remain unclear. Here, we utilized a Retention Using Selective Hook system to analyze molecular mechanisms that regulate the secretion of IGF2. We found that a type I transmembrane protein, TMED10, is essential for the secretion of IGF2 and for differentiation of mouse myoblast C2C12 cells. Further analyses indicate that the residues 112-140 in IGF2 are important for the secretion of IGF2 and these residues directly interact with the GOLD domain of TMED10. We then reconstituted the release of IGF2 into COPII vesicles. This assay suggests that TMED10 mediates the packaging of IGF2 into COPII vesicles to be efficiently delivered to the Golgi. Moreover, TMED10 also mediates ER export of TGN-localized cargo receptor, sortilin, which subsequently mediates TGN export of IGF2. These analyses indicate that TMED10 is critical for IGF2 secretion by directly regulating ER export and indirectly regulating TGN export of IGF2, providing insights into trafficking of IGF2 for myoblast differentiation.

Development and validation of a vesicle-mediated transport-associated gene signature for predicting prognosis and immune therapy response in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignant tumor with a poor prognosis. The progression of numerous malignancies has been linked to abnormal vesicle-mediated transport-related gene (VMTRG) expression. The prognostic importance of VMTRGs in HCC is uncertain nonetheless.

METHODS

Utilizing HCC data from TCGA and ICGC, we employed univariate cox analysis, unsupervised clustering, and lasso analysis to construct molecular subtypes and prognostic signature of HCC based on the prognostic-associated VMTRGs expression levels. Subsequently, we validated the expression levels of the signature genes. We investigated the probable pathways using gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA). Six methods were utilized to compare immune cell infiltration between two risk groups. Moreover, the "pRRophetic" algorithm was utilized to test the drug sensitivity of both groups.

RESULTS

We identified two distinct subtypes with divergent biological behaviors and immune functionality through unsupervised clustering. Subtype C1 demonstrated a poorer prognosis. A prognostic signature incorporating two VMTRGs (KIF2C and RAC1) was formulated. Immunohistochemistry and qRT-PCR analyses unveiled a significant upregulation of these pivotal genes within HCC tissues. The prognosis was worse for the high-risk group, which also had a higher clinicopathological grade, higher levels of tumor mutation burden (TMB), a higher immunological infiltration of CD8 + T cells, a higher expression of immune checkpoints, and enhanced immunotherapy efficacy. These two risk groups also have varied chemotherapy drug sensitivities.

CONCLUSIONS

Based on VMTRGs, we have developed a signature that assists in accurate prognosis prediction and formulating personalized treatment strategies for HCC patients.

Lysosomal proteomics reveals mechanisms of neuronal apoE4associated lysosomal dysfunction

ApoE4 is the primary risk factor for Alzheimer's Disease. While apoE is primarily expressed by astrocytes, AD pathology including endosomal abnormalities and mitochondrial dysfunction first occurs in neurons. Lysosomes are poised at the convergence point between these features. We find that apoE4-expressing cells exhibit lysosomal alkalinization, reduced lysosomal proteolysis, and impaired mitophagy. To identify driving factors for this lysosomal dysfunction, we performed quantitative lysosomal proteome profiling. This revealed that apoE4 expression results in lysosomal depletion of Lgals3bp and accumulation of Tmed5 in both Neuro-2a cells and postmitotic human neurons. Modulating the expression of both proteins affected lysosomal function, with Tmed5 knockdown rescuing lysosomal alkalinization in apoE4 cells, and Lgals3bp knockdown causing lysosomal alkalinization and reduced lysosomal density in apoE3 cells. Taken together, our work reveals that apoE4 exerts gain-of-toxicity by alkalinizing the lysosomal lumen, pinpointing lysosomal Tmed5 accumulation and Lgals3bp depletion as apoE4-associated drivers for this phenotype.

Genetic characterization of C. elegans TMED genes

BACKGROUND

p24/transmembrane Emp24 domain (TMED) proteins are a set of evolutionarily conserved, single pass transmembrane proteins that have been shown to facilitate protein secretion and selection of cargo proteins to transport vesicles in the cellular secretion pathway. However, their functions in animal development are incompletely understood.

RESULTS

The C. elegans genome encodes eight identified TMED genes, with at least one member from each defined subfamily (α, β, γ, δ). TMED gene mutants exhibit a shared set of defects in embryonic viability, animal movement, and vulval morphology. Two γ subfamily genes, tmed-1 and tmed-3, exhibit the ability to compensate for each other, as defects in movement and vulva morphology are only apparent in double mutants. TMED mutants also exhibit a delay in breakdown of basement membrane during vulva development.

CONCLUSIONS

The results establish a genetic and experimental framework for the study of TMED gene function in C. elegans, and argue that a functional protein from each subfamily is important for a shared set of developmental processes. A specific function for TMED genes is to facilitate breakdown of the basement membrane between the somatic gonad and vulval epithelial cells, suggesting a role for TMED proteins in tissue reorganization during animal development.

TMED10 mediates the loading of neosynthesised Sonic Hedgehog in COPII vesicles for efficient secretion and signalling

The morphogen Sonic Hedgehog (SHH) plays an important role in coordinating embryonic development. Short- and long-range SHH signalling occurs through a variety of membrane-associated and membrane-free forms. However, the molecular mechanisms that govern the early events of the trafficking of neosynthesised SHH in mammalian cells are still poorly understood. Here, we employed the retention using selective hooks (RUSH) system to show that newly-synthesised SHH is trafficked through the classical biosynthetic secretory pathway, using TMED10 as an endoplasmic reticulum (ER) cargo receptor for efficient ER-to-Golgi transport and Rab6 vesicles for Golgi-to-cell surface trafficking. TMED10 and SHH colocalized at ER exit sites (ERES), and TMED10 depletion significantly delays SHH loading onto ERES and subsequent exit leading to significant SHH release defects. Finally, we utilised the Drosophila wing imaginal disc model to demonstrate that the homologue of TMED10, Baiser (Bai), participates in Hedgehog (Hh) secretion and signalling in vivo. In conclusion, our work highlights the role of TMED10 in cargo-specific egress from the ER and sheds light on novel important partners of neosynthesised SHH secretion with potential impact on embryonic development.

A spatiotemporal Notch interaction map from plasma membrane to nucleus

Notch signaling relies on ligand-induced proteolysis of the transmembrane receptor Notch to liberate a nuclear effector that drives cell fate decisions. Upon ligand binding, sequential cleavage of Notch by the transmembrane protease ADAM10 and the intracellular protease γ-secretase releases the Notch intracellular domain (NICD), which translocates to the nucleus and forms a complex that induces target gene transcription. To map the location and timing of the individual steps required for the proteolysis and movement of Notch from the plasma membrane to the nucleus, we used proximity labeling with quantitative, multiplexed mass spectrometry to monitor the interaction partners of endogenous NOTCH2 after ligand stimulation in the presence of a γ-secretase inhibitor and as a function of time after inhibitor removal. Our studies showed that γ-secretase-mediated cleavage of NOTCH2 occurred in an intracellular compartment and that formation of nuclear complexes and recruitment of chromatin-modifying enzymes occurred within 45 min of inhibitor washout. These findings provide a detailed spatiotemporal map tracking the path of Notch from the plasma membrane to the nucleus and identify signaling events that are potential targets for modulating Notch activity.

A novel human cellular model of CDA IV enables comprehensive analysis revealing the molecular basis of the disease phenotype

Red blood cell disorders can result in severe anemia. One such disease congenital dyserythropoietic anemia IV (CDA IV) is caused by the heterozygous mutation E325K in the transcription factor KLF1. However, studying the molecular basis of CDA IV is severely impeded by the paucity of suitable and adequate quantities of material from patients with anemia and the rarity of the disease. We, therefore, took a novel approach, creating a human cellular disease model system for CDA IV that accurately recapitulates the disease phenotype. Next, using comparative proteomics, we reveal extensive distortion of the proteome and a wide range of disordered biological processes in CDA IV erythroid cells. These include downregulated pathways the governing cell cycle, chromatin separation, DNA repair, cytokinesis, membrane trafficking, and global transcription, and upregulated networks governing mitochondrial biogenesis. The diversity of such pathways elucidates the spectrum of phenotypic abnormalities that occur with CDA IV and impairment to erythroid cell development and survival, collectively explaining the CDA IV disease phenotype. The data also reveal far more extensive involvement of KLF1 in previously assigned biological processes, along with novel roles in the regulation of intracellular processes not previously attributed to this transcription factor. Overall, the data demonstrate the power of such a model cellular system to unravel the molecular basis of disease and how studying the effects of a rare mutation can reveal fundamental biology.

Impact of sphingolipids on protein membrane trafficking

Membrane trafficking is essential to maintain the spatiotemporal control of protein and lipid distribution within membrane systems of eukaryotic cells. To achieve their functional destination proteins are sorted and transported into lipid carriers that construct the secretory and endocytic pathways. It is an emerging theme that lipid diversity might exist in part to ensure the homeostasis of these pathways. Sphingolipids, a chemical diverse type of lipids with special physicochemical characteristics have been implicated in the selective transport of proteins. In this review, we will discuss current knowledge about how sphingolipids modulate protein trafficking through the endomembrane systems to guarantee that proteins reach their functional destination and the proposed underlying mechanisms.

When it doesn't run in the blood(vessels) - events involved in vascular disorders

In the current issue of the Biomedical Journal the underlying pathology of hemodynamic compromise in acute small subcortical infarction are elucidated. A follow-up study in patients with childhood Kawasaki disease is presented, as well as an insight into the gradually decreasing antigen expression in cases of acute myeloid leukemia. Furthermore this issue provides an exciting update concerning COVID-19 and the use of CRISPR-Cas, a review about computational approaches in the research of kidney stone formation, factors connected to central precocious puberty, and why a rock star of paleogenetics recently received a Nobel Prize. Additionally, this issue contains an article proposing the repurposing of the lung cancer drug Capmatinib, a study of how the gut microbiome develops in neonates, an impulse about the role of the transmembrane protein TMED3 in esophageal carcinoma, and the revelation about how competing endogenous RNA influences ischemic stroke. Lastly, genetic reasons for male infertility are discussed, as well as the relation between non-alcoholic fatty liver disease and chronic kidney disease.

The many hats of transmembrane emp24 domain protein TMED9 in secretory pathway homeostasis

The secretory pathway is an intracellular highway for the vesicular transport of newly synthesized proteins that spans the endoplasmic reticulum (ER), Golgi, lysosomes and the cell surface. A variety of cargo receptors, chaperones, and quality control proteins maintain the smooth flow of cargo along this route. Among these is vesicular transport protein TMED9, which belongs to the p24/transmembrane emp24 domain (TMED) family of proteins, and is expressed across vertebrate species. The TMED family is comprised of structurally-related type I transmembrane proteins with a luminal N-terminal Golgi-dynamics domain, a luminal coiled-coil domain, a transmembrane domain and a short cytosolic C-terminal tail that binds COPI and COPII coat proteins. TMED9, like other members of the TMED family, was first identified as an abundant constituent of the COPI and COPII coated vesicles that mediate traffic between the ER and the Golgi. TMED9 is typically purified in hetero-oligomers together with TMED family members, suggesting that it may function as part of a complex. Recently, TMED family members have been discovered to play various roles in secretory pathway homeostasis including secreted protein processing, quality control and degradation of misfolded proteins, and post-Golgi trafficking. In particular, TMED9 has been implicated in autophagy, lysosomal sorting, viral replication and cancer, which we will discuss in this Mini-Review.

Screening of the novel immune-suppressive biomarkers of TMED family and whether knockdown of TMED2/3/4/9 inhibits cell migration and invasion in breast cancer

Background

Transmembrane p24 trafficking protein (TMED) family members are implicated in several solid tumors, but their clinical relevance for breast cancer (BC) remains unclear. This study aimed to probe their prognostic values and relations with tumor immunity in BC.

Methods

TMED family mRNA expression was assessed in five microarray datasets (GSE65212, GSE42568, GSE5364, GSE22820 and GSE45827) from Gene Expression Omnibus (GEO) database and invasive breast cancer (BRCA) cohort from The Cancer Genome Atlas (TCGA). Receiver operating characteristic (ROC) curve was performed to determine the predictive values of filtered members of the TMED family. The protein expressions of screen genes were validated by Clinical Proteomic Tumor Analysis Consortium (CPTAC) data from University of ALabama at Birmingham CANcer data analysis portal (UALCAN) and detected in the clinical specimens by western blot assay. Clinicopathologic variables were analyzed with bc-GenExMiner, and patient prognostic data were obtained with Kaplan-Meier Plotter. In vitro wound healing and invasion assays were performed on siRNA-transfected BC cell lines. TIMER 2.0, SangerBox, and ImmPort were used to evaluate tumor immune infiltration, immune checkpoints, and other immune-related genes. CbioPortal, Metascape, Expression2kinases, and LinkedOmics were used to explore gene regulatory network.

Results

BC tissues expressed TMED2/3/4/9 at a higher level than normal tissues, providing diagnostic potential. All the areas under the ROC curve for TMED2/3/4/9 were more than 0.7. TMED2/3/4/9 correlated with numerous clinical variables, including lymph node status, Scarff-Bloom-Richardson score (SBR), Nottingham Prognostic Index (NPI), estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and triple-negative breast cancer (TNBC) status, and their high expression predicted the poor prognosis of BC patients. TMED2/3/4/9 knockdown drastically inhibited the migratory and invasive capacities of MDA-MB-231 and HCC1937 cells. TMED2/3/4/9 expressions correlated negatively with the infiltration of tumor-suppressive immune cells such as CD8⁺ T cells, dendritic cells, and natural killer cells, and was inversely related to a variety of immune checkpoint genes, including programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA4). A set of kinases, transcription factors, and microRNAs (miRNAs) may regulate TMED2/3/4/9 abnormalities at the genome level.

Conclusions

TMED2/3/4/9 may serve as diagnostic, prognostic, and immune-suppressive biomarkers in BC.

Vesicle-mediated transport-related genes are prognostic predictors and are associated with tumor immunity in lung adenocarcinoma

Background

Globally, lung adenocarcinoma (LUAD) is the leading cause of cancer-related deaths. It is a progressive disorder that arises from multiple genetic and environmental factors. Dysregulated expression of vesicle-mediated transport-related genes (VMTRGs) have been reported in several cancers. However, the prognostic significance of VMTRGs in LUAD has yet to be established.

Methods

The VMTRG profiling data for 482 LUAD patients and 59 normal controls were downloaded from The Cancer Genome Altas (TCGA). Univariate Cox regression and Least Absolute Shrinkage and Selection Operator (LASSO) regression analyses were performed to construct and optimize the risk model. Several GEO datasets were used to validate the risk model. The roles of these genes were investigated via the Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) enrichment analyses. Differences in immune cell infiltrations between risk groups were evaluated using five algorithms. "pRRophetic" was used to investigate anti-cancer drug sensitivities in two groups. Expression of these five genes in LUAD samples and adjacent normal tissues were evaluated by qRT-PCR. Colony formation and wound healing assays were performed to assess the significance of CNIH1 and AP3S1 in LUAD cells.

Results

We identified 85 prognosis-associated VMTRGs that could be constructed a risk model for LUAD patients, indicating their potential importance in LUAD development. The risk model including the five VMTRGs (CNIH1, KIF20A, GALNT2, GRIA1, and AP3S1) was associated with clinical outcomes. Tumor stage and risk score were found to be independent prognostic factors for LUAD patients. The five VMTRGs were also correlated with activation of the Notch and p53 signaling pathways. The risk model was significantly associated with immune responses and with high-level expression of immune checkpoints. High-risk group patients were more sensitive to several chemotherapeutic drugs and Lapatinib. Furthermore, CNIH1 and AP3S1 promoted LUAD cell growth and migration in vitro.

Conclusion

We constructed a VMTRG-based risk model for effective prediction of prognostic outcomes for LUAD patients. The risk model was associated with immune infiltration levels. These five hub genes are potential targets for immune therapy combined with chemotherapy in LUAD.

TMED9 Expression Level as a Biomarker of Epithelial Ovarian Cancer Progression and Prognosis

BACKGROUND

Transmembrane emp24 domain-containing protein 9 (TMED9) belongs to the TMED/p24 family that transports, modifies, and packs proteins and lipids into vesicles for delivery to specific locations and is important in innate immune signaling via the endoplasmic reticulum-Golgi cargo pathway. TMED9 has been implicated in various cancer types; however, its role in epithelial ovarian cancer (EOC) is unclear. In this study, we aimed to elucidate the role and clinical significance of TMED9 in EOC.

MATERIALS AND METHODS

mRNA and protein levels of TMED9 and their associations with clinicopathological features in EOCs were evaluated using RNA-sequencing and immunohistochemistry data. Functional studies assessing the tumorigenic role of TMED9 in EOC cell lines were also performed.

RESULTS

The mRNA expression of TMED9 was up-regulated in EOC compared to that in normal ovarian epithelium. TMED9 protein expression increased in progression from normal ovarian epithelium to EOC (p<0.001). Moreover, high expression of TMED9 was associated with advanced stage, serous cell type and poor histological grade in EOC and demonstrated independent prognostic significance for both disease-free and overall survival. Further functional studies showed that TMED9 knockdown reduced migration, invasion, cell proliferation, and colony formation of EOC cells.

CONCLUSION

Overall, our results support the use of TMED9 as a valuable prognostic biomarker and provide evidence for targeting of TMED9 as a novel strategy for EOC treatment.

Identification of in vivo induced antigens of the malacosporean parasite Tetracapsuloides bryosalmonae (Cnidaria) using in vivo induced antigen technology

Tetracapsuloides bryosalmonae is a malacosporean endoparasite that causes proliferative kidney disease (PKD) in wild and farmed salmonids in Europe and North America. The life cycle of T. bryosalmonae completes between invertebrate bryozoan and vertebrate fish hosts. Inside the fish, virulence factors of T. bryosalmonae are induced during infection or interactions with host cells. T. bryosalmonae genes expressed in vivo are likely to be important in fish pathogenesis. Herein, we identify in vivo induced antigens of T. bryosalmonae during infection in brown trout (Salmo trutta) using in vivo induced antigen technology (IVIAT). Brown trout were exposed to the spores of T. bryosalmonae and were sampled at different time points. The pooled sera were first pre-adsorbed with antigens to remove false positive results. Subsequently, adsorbed sera were used to screen a T. bryosalmonae cDNA phage expression library. Immunoscreening analysis revealed 136 immunogenic T. bryosalmonae proteins induced in brown trout during parasite development. They are involved in signal transduction, transport, metabolism, ion-protein binding, protein folding, and also include hypothetical proteins, of so far unknown functions. The identified in vivo induced antigens will be useful in the understanding of T. bryosalmonae pathogenesis during infection in susceptible hosts. Some of the antigens found may have significant implications for the discovery of candidate molecules for the development of potential therapies and preventive measures against T. bryosalmonae in salmonids.

Analysis and Validation of TMED3 correlates with poor prognosis and tumor immune infiltration of glioma

BACKGROUND

Glioma is the most common primary intracranial tumor. It is notorious for its high degree of malignancy, strong invasion, and poor prognosis. The transmembrane emp24 trafficking protein 3 (TMED3) belongs to the TMED family, which is responsible for intracellular protein transport and innate immune signal transmission. More and more evidence shows that TMED3 plays a key role in the tumor progression of human cancer. However, the role and potential molecular mechanism of TMED3 in glioma have not been clarified.

METHODS

TMED3 expression levels, clinical data, survival prognosis, prediction of upstream miRNA, and immune-related analyses were all analyzed utilizing relevant databases. Finally, a molecular cell experiment confirmed TMED3 expression in glioma.

RESULTS

We discovered that TMED3 is overexpressed in most tumors, including gliomas, and is associated with tumor staging and prognosis. Subsequently, a combination of a series of bioinformatics analyses, including correlation and survival analyses, identified miR-1296-5p as the most potent upstream miRNA of TMED3 in gliomas.Additionally, we analyzed the relationship between TMED3 level and tumor immune cell infiltration and immune checkpoint expression.

CONCLUSION

TMED3 is highly expressed in gliomas and is associated with tumor staging and affects the prognosis of patients. Therefore, the TMED3 gene may be a potential immunotherapy target and prognostic marker for gliomas.

The structural and functional divergence of a neglected three-finger toxin subfamily in lethal elapids

Bungarus multicinctus is a widely distributed and medically important elapid snake that produces lethal neurotoxic venom. To study and enhance existing antivenom, we explore the complete repertoire of its toxin genes based on de novo chromosome-level assembly and multi-tissue transcriptome data. Comparative genomic analyses suggest that the three-finger toxin family (3FTX) may evolve through the neofunctionalization of flanking LY6E. A long-neglected 3FTX subfamily (i.e., MKA-3FTX) is also investigated. Only one MKA-3FTX gene, which evolves a different protein conformation, is under positive selection and actively transcribed in the venom gland, functioning as a major toxin effector together with MKT-3FTX subfamily homologs. Furthermore, this lethal snake may acquire self-resistance to its β-bungarotoxin via amino acid replacements on fast-evolving KCNA2. This study provides valuable resources for further evolutionary and structure-function studies of snake toxins, which are fundamental for the development of effective antivenoms and drug candidates.

Heterologous Expression and Evaluation of Novel Plasmodium falciparum Transmission Blocking Vaccine Candidates

Malaria transmission blocking vaccines (TBV) aim to induce antibodies that can interrupt Plasmodium falciparum development in the mosquito midgut and thereby prevent onward malaria transmission. A limited number of TBV candidates have been identified and only three (Pfs25, Pfs230 and Pfs48/45) have entered clinical testing. While one of these candidates may emerge as a highly potent TBV candidate, it is premature to determine if they will generate sufficiently potent and sustained responses. It is therefore important to explore novel candidate antigens. We recently analyzed sera from naturally exposed individuals and found that the presence and/or intensity of antibodies against 12 novel putative surface expressed gametocyte antigens was associated with transmission reducing activity. In this study, protein fragments of these novel TBV candidates were designed and heterologously expressed in Drosophila melanogaster S2 cells and Lactococcus lactis. Eleven protein fragments, covering seven TBV candidates, were successfully produced. All tested antigens were recognized by antibodies from individuals living in malaria-endemic areas, indicating that native epitopes are present. All antigens induced antigen-specific antibody responses in mice. Two antigens induced antibodies that recognized a native protein in gametocyte extract, and antibodies elicited by four antigens recognized whole gametocytes. In particular, we found that antigen Pf3D7_0305300, a putative transporter, is abundantly expressed on the surface of gametocytes. However, none of the seven novel TBV candidates expressed here induced an antibody response that reduced parasite development in the mosquito midgut as assessed in the standard membrane feeding assay. Altogether, the antigen fragments used in this study did not prove to be promising transmission blocking vaccine constructs, but led to the identification of two gametocyte surface proteins that may provide new leads for studying gametocyte biology.

TMED2 binding restricts SMO to the ER and Golgi compartments

Hedgehog (HH) signaling is important for embryonic pattering and stem cell differentiation. The G protein–coupled receptor (GPCR) Smoothened (SMO) is the key HH signal transducer modulating both transcription-dependent and transcription-independent responses. We show that SMO protects naive mouse embryonic stem cells (ESCs) from dissociation-induced cell death. We exploited this SMO dependency to perform a genetic screen in haploid ESCs where we identify the Golgi proteins TMED2 and TMED10 as factors for SMO regulation. Super-resolution microscopy shows that SMO is normally retained in the endoplasmic reticulum (ER) and Golgi compartments, and we demonstrate that TMED2 binds to SMO, preventing localization to the plasma membrane. Mutation of TMED2 allows SMO accumulation at the plasma membrane, recapitulating early events after HH stimulation. We demonstrate the physiologic relevance of this interaction in neural differentiation, where TMED2 functions to repress HH signal strength. Identification of TMED2 as a binder and upstream regulator of SMO opens the way for unraveling the events in the ER–Golgi leading to HH signaling activation.

Hedgehog signals orchestrate tissue patterning by binding the receptor Patched and restricting the signal transducer Smoothened. A genetic screen reveals Tmed2 as a new interactor of Smoothened that is required for regulating Smoothened transport from the endoplasmic reticulum and Golgi to the plasma membrane and hence modulating the strength of Hedgehog signal transduction.

Trafficking Protein TMED3 Promotes Esophageal Squamous Cell Carcinoma

BACKGROUND

The molecular mechanisms of esophageal squamous cell carcinoma (ESCC) remain poorly understood. Transmembrane emp24 trafficking protein 3 (TMED3) acts as an oncogene or tumor suppressor gene in different cancers. Our study was to explore the clinicopathological significance and functional roles of TMED3 in ESCC.

METHODS

Immunohistochemistry, qPCR, and western blotting were used to analyze the expression of TMED3 in ESCC tissues and cells. Statistical analysis was performed to analyze the relationship between TMED3 expression and tumor characteristics in patients with ESCC. The role of TMED3 in vitro and in vivo was investigated by performing functional verification experiments and using a xenograft mouse model. Proteins that are functionally related to TMED3 were recognized by Affymetrix microarray and Ingenuity Pathway Analysis (IPA). Functional verification experiments were performed to analyze the role of FAM60A (a protein functionally related to TMED3) in vitro.

RESULTS

We confirmed the overexpression of TMED3 was correlated with poor prognosis in ESCC patients. When TMED3 was knocked down, ESCC cell proliferation, migration, and invasion were inhibited whereas cell apoptosis was promoted in vitro, and tumorigenicity was inhibited in vivo. We further revealed significant changes in gene expression profile in TMED3 knockdown cells. Among these differentially expressed genes, FAM60A was overexpressed in ESCC tissues. Furthermore, knocking down FAM60A significantly weakened the proliferation ability of ESCC cells and reversed TMED3's tumorigenicity of ESCC cells.

CONCLUSION

Our study revealed an oncogenic role of TMED3 in ESCC.

A gold revision of the Golgi Dynamics (GOLD) domain structure and associated cell functionalities

The classical secretory pathway is the key membrane-based delivery system in eukaryotic cells. Several families of proteins involved in the secretory pathway, with functionalities going from cargo sorting receptors to the maintenance and dynamics of secretory organelles, share soluble globular domains predicted to mediate protein-protein interactions. One of them is "Golgi Dynamics" (GOLD) domain, named after its strong association with the Golgi apparatus. There are many GOLD-containing protein families, such as the Transmembrane emp24 domain-containing proteins (TMED/p24 family), animal SEC14-like proteins, Human Golgi resident protein ACBD3, a splice variant of TICAM2 called TRAM with GOLD domain and FYCO1. Here, we critically review the state-of-the-art knowledge of the structures and functions of the main representatives of GOLD-containing proteins in vertebrates. We provide the first unified description of the GOLD domain structure across different families since the first high-resolution structure was determined. With a brand-new update on the definition of the GOLD domain, we also discuss how its tertiary structure fits the β-sandwich-like fold map and give exciting new directions for forthcoming studies.

Oncosuppressive and oncogenic activity of the sphingolipid-metabolizing enzyme β-galactosylceramidase

β-galactosylceramidase (GALC) is a lysosomal enzyme that removes β-galactose from β-galactosylceramide, leading to the formation of the oncosuppressor metabolite ceramide. Recent observations have shown that GALC may exert opposite effects on tumor growth by acting as an oncosuppressive or oncogenic enzyme depending on the different experimental approaches, in vitro versus in vivo observations, preclinical versus clinical findings, and tumor type investigated. This review will recapitulate and discuss the contrasting experimental evidence related to the impact of GALC on the biological behavior of cancer and stromal cells and its contribution to tumor progression.

Early Secretory Pathway-Associated Proteins SsEmp24 and SsErv25 Are Involved in Morphogenesis and Pathogenicity in a Filamentous Phytopathogenic Fungus

Proper protein secretion is critical for fungal development and pathogenesis. However, the potential roles of proteins involved in the early secretory pathway are largely undescribed in filamentous fungi. p24 proteins are cargo receptors that cycle between the endoplasmic reticulum (ER) and Golgi apparatus in the early secretory pathway and recruit cargo proteins to nascent vesicles. This study characterized the function of two p24 family proteins (SsEmp24 and SsErv25) in a phytopathogenic fungus, Sclerotinia sclerotiorum. Both SsEmp24 and SsErv25 were upregulated during the early stages of S. sclerotiorum infection. ΔSsEmp24 mutant and ΔSsErv25 mutant displayed abnormal vegetative growth and sclerotium formation, were defective in infection cushion formation, and showed lower virulence on host plants. ΔSsEmp24 mutant had a more severe abnormal phenotype than ΔSsErv25 mutant, implying that SsEmp24 could play a central role in the early secretory pathway. Similar to their Saccharomyces cerevisiae counterparts, SsEmp24 interacted with SsErv25 and predominantly colocalized in the ER or nuclear envelope. The absence of SsEmp24 or SsErv25 led to defective in protein secretion in S. sclerotiorum, including the pathogenicity-related extracellular hydrolytic enzymes and effectors. It is proposed that SsEmp24 and SsErv25, components in the early secretory pathway, are involved in modulating morphogenesis and pathogenicity in S. sclerotiorum by mediating protein secretion. IMPORTANCE Understanding the reproduction and pathogenesis mechanism of phytopathogens could provide new opinions to effectively control fungal diseases. Although it has been known that effectors and extracellular hydrolytic enzymes secreted by phytopathogenic fungi play important roles in fungus-host interactions, the secretion system for the delivery of virulence factors to the host is still largely undescribed. Although the role of the early secretory pathway-associated p24 proteins in S. cerevisiae has been well characterized, the function of these proteins in filamentous fungi was scarcely known prior to this study. The present research provides evidence that p24 proteins participate in the reproduction and pathogenesis of phytopathogenic fungi through the mediation of protein secretion. This research advances our understanding of p24 proteins in filamentous phytopathogenic fungi. In addition, the candidate cargos of the two p24 proteins, SsEmp24 and SsErv25, were screened out by comparative proteomics, which could aid the identification of novel development and virulence-associated factors in phytopathogenic fungi.

Multi-Omics Analysis Identified TMED2 as a Shared Potential Biomarker in Six Subtypes of Human Cancer

Introduction

Cancer is one of the most common malignancies and the leading cause of death worldwide. As a member of the transmembrane emp24 domain (Tmed)/p24 family of proteins, TMED2 expression variations have been documented earlier in only a few subtypes of human cancers, and the multi-omics profiling of TMED2 as a shared biomarker in different other subtypes of human cancers remains to be uncovered.

Methods

In the current study, TMED2 multi-omics analysis in 24 major subtypes of human cancer was performed using different authentic online databases and bioinformatics analysis including UALCAN, Kaplan–Meier (KM) plotter, Human Protein Atlas (HPA), GENT2, MEXPRESS, cBioportal, STRING, DAVID, TIMER, and CTD.

Results

In general, the TMED2 expression in 24 major subtypes of human cancers was higher relative to normal controls and was also strongly associated with the lower overall survival (OS) and relapse-free survival (RFS) duration of CESC, ESCA, HNSC, KIRC, LIHC, and LUAD patients. This implies that TMED2 plays a significant role in the development and progression of these cancers. Furthermore, the TMED2 overexpression was also correlated with different clinicopathological features of CESC, ESCA, HNSC, KIRC, LIHC, and LUAD patients. TMED2-associated genes network was involved in 3 diverse pathways, and finally, few stronger correlations were also explored between TMED2 expression and its promoter methylation level, genetic alterations, and CD8+ T immune cells level.

Conclusion

In conclusion, via this in silico study, we have elucidated that TMED2 can serve as a shared diagnostic and prognostic biomarker in CESC, ESCA, HNSC, KIRC, LIHC, and LUAD patients of different clinicopathological features but, further in vitro and in vivo research should be carried out to confirm these findings.

High expression of transmembrane P24 trafficking protein 9 predicts poor prognosis in breast carcinoma

Over the years, molecular subtypes based on estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER-2) status have been observed to effectively guide decision-making for the optimal treatment of patients with breast carcinoma (BRCA). However, despite this progress, there are still more than 41,000 BRCA-related fatalities each year in the United States. Moreover, effective drug targets for triple-negative breast carcinoma (TNBC) are still lacking. Given its high mortality rate, it is necessary to investigate more biomarkers with prognostic and pathological relevance in BRCA. In our study, we examined the expression patterns and prognostic implications of transmembrane P24 trafficking protein 9 (TMED9) in BRCA using multiple public cohorts and BRCA specimens collected from Shanghai General Hospital. In addition to this, in vitro experiments were also performed to evaluate the effects of TMED9 expression in BRCA cell proliferation and migration. Our results have demonstrated that a high expression of TMED9 promoted BRCA cell proliferation and migration and predicted poor prognosis in patients with BRCA. In conclusion, TMED9 is a potential prognostic indicator and a possible drug target of BRCA.

PAM: diverse roles in neuroendocrine cells, cardiomyocytes, and green algae

Our understanding of the ways in which peptides are used for communication in the nervous and endocrine systems began with the identification of oxytocin, vasopressin, and insulin, each of which is stored in electron-dense granules, ready for release in response to an appropriate stimulus. For each of these peptides, entry of its newly synthesized precursor into the ER lumen is followed by transport through the secretory pathway, exposing the precursor to a sequence of environments and enzymes that produce the bioactive products stored in mature granules. A final step in the biosynthesis of many peptides is C-terminal amidation by peptidylglycine α-amidating monooxygenase (PAM), an ascorbate- and copper-dependent membrane enzyme that enters secretory granules along with its soluble substrates. Biochemical and cell biological studies elucidated the highly conserved mechanism for amidated peptide production and raised many questions about PAM trafficking and the effects of PAM on cytoskeletal organization and gene expression. Phylogenetic studies and the discovery of active PAM in the ciliary membranes of Chlamydomonas reinhardtii, a green alga lacking secretory granules, suggested that a PAM-like enzyme was present in the last eukaryotic common ancestor. While the catalytic features of human and C. reinhardtii PAM are strikingly similar, the trafficking of PAM in C. reinhardtii and neuroendocrine cells and secretion of its amidated products differ. A comparison of PAM function in neuroendocrine cells, atrial myocytes, and C. reinhardtii reveals multiple ways in which altered trafficking allows PAM to accomplish different tasks in different species and cell types.

STING Operation at the ER/Golgi Interface

DNA is present in the nucleus and mitochondria of eukaryotic cells. There are, however, certain instances in which DNA emerges in the cytosol. The two major sources of cytosolic DNA are self DNA that is leaked out from the nucleus or mitochondria, and non-self DNA from DNA viruses. The cytosolic DNA triggers the host immune response. Recent studies have identified two key molecules, cyclic GMP-AMP (cGAMP) synthase (cGAS) and stimulator of interferon genes (STING) in this immune response. STING is an endoplasmic reticulum (ER) protein. After STING binding to cGAMP, STING exits the ER and translocates to the Golgi, where STING triggers the type I interferon- and proinflammatory responses through the activation of interferon regulatory factor 3 (IRF3) and nuclear factor-kappa B (NF-κB). STING also activates other cellular responses including cell senescence, autophagy, and cell death. In this review, we focus on emerging issues regarding the regulation of STING by membrane traffic, with a particular focus on the retrograde membrane traffic from the Golgi to the ER. The retrograde membrane traffic is recently shown by us and others to be critical for silencing the STING signaling pathway and the defect in this traffic underlies the pathogenesis of the COPA syndrome, a monogenic autoinflammatory disease caused by missense mutations of coatomer protein complex subunit α (COP-α).

Proteomics-based identification of TMED9 is linked to vascular invasion and poor prognoses in patients with hepatocellular carcinoma

BACKGROUND

Due to the difficulties in early diagnosing and treating hepatocellular carcinoma (HCC), prognoses for patients remained poor in the past decade. In this study, we established a screening model to discover novel prognostic biomarkers in HCC patients.

METHODS

Candidate biomarkers were screened by liquid chromatography with tandem mass spectrometry (LC-MS/MS) analyses of five HCC normal (N)/tumor (T) paired tissues and preliminarily verified them through several in silico database analyses. Expression levels and functional roles of candidate biomarkers were respectively evaluated by immunohistochemical staining in N/T paired tissue (n = 120) and MTS, colony formation, and transwell migration/invasion assays in HCC cell lines. Associations of clinicopathological features and prognoses with candidate biomarkers in HCC patients were analyzed from GEO and TCGA datasets and our recruited cohort.

RESULTS

We found that the transmembrane P24 trafficking protein 9 (TMED9) protein was elevated in HCC tissues according to a global proteomic analysis. Higher messenger (m)RNA and protein levels of TMED9 were observed in HCC tissues compared to normal liver tissues or pre-neoplastic lesions. The TMED9 mRNA expression level was significantly associated with an advanced stage and a poor prognosis of overall survival (OS, p = 0.00084) in HCC patients. Moreover, the TMED9 protein expression level was positively correlated with vascular invasion (p = 0.026), OS (p = 0.044), and disease-free survival (p = 0.015) in our recruited Taiwanese cohort. In vitro, manipulation of TMED9 expression in HCC cells significantly affected cell migratory, invasive, proliferative, and colony-forming abilities.

CONCLUSIONS

Ours is the first work to identify an oncogenic role of TMED9 in HCC cells and may provide insights into the application of TMED9 as a novel predictor of clinical outcomes and a potential therapeutic target in patients with HCC.

Knockdown of TMED3 inhibits cell viability and migration and increases apoptosis in human chordoma cells

Chordoma is a rare low‑grade tumor of the axial skeleton. Over previous decades, a range of targeted drugs have been used for treating chordoma, with more specific and effective therapies under investigation. Transmembrane Emp24 protein transport domain containing 3 (TMED3) is a novel gene reported to be a regulator of oncogenesis, cancer development and metastasis; however, its role in chordoma remains unclear. In the present study, the expression of TMED3 was investigated in chordoma cells, and the effect of TMED3 knockdown on chordoma development was examined in vitro and in vivo, followed by exploration of differentially expressed proteins in TMED3‑silenced chordoma cells via an apoptosis antibody array. Reverse transcription‑quantitative PCR and western blot assays were performed to determine the expression levels. It was revealed that TMED3 was highly expressed in chordoma, and that knockdown of TMED3 inhibited cell viability and migration, and enhanced the apoptosis of chordoma cells. Additionally, knockdown of TMED3 inhibited the expression of Bcl‑2, heat shock protein 27, insulin‑like growth factor (IGF)‑I, IGF‑II, IGF binding protein‑2, Livin, Akt, CDK6 and cyclin D1 proteins, whereas MAPK9 was upregulated. Furthermore, a xenograft nude mice model demonstrated that TMED3 expression promoted tumor growth. Collectively, the present findings suggested that knockdown of TMED3 inhibited cell viability and migration, and enhanced apoptosis in chordoma cells, and that TMED3 may be a novel target for chordoma therapy.

Expression and Importance of TMED2 in Multiple Myeloma Cells

Objective

TMED2 is a member of the transmembrane emp24 domain (Tmed)/p24 protein family, which is significantly upregulated in breast cancer, ovarian cancer and other tumour tissues. The purpose of this study was to investigate the expression of TMED2 in MM cell lines and its effect on the biological behaviour of MM cell lines.

Methods

Real-time quantitative PCR (RT-qPCR) was used to detect the expression of TMED2 in MM cell lines, including MM.1S and RPMI 8226 cells, and lentivirus vector-mediated TMED2 gene silencing was used to further study the effect of the downregulation of TMED2 expression on cell viability, the cell cycle, and apoptosis.

Results

Based on the RT-qPCR results, the expression of the TMED2 mRNA was increased in the MM cell lines MM.1S and RPMI 8226 compared with endogenous control GAPDH. The expression of the TMED2 mRNA was substantially reduced after transfection of the shRNA targeting TMED2 (shTMED2) in both MM cell lines. The CCK-8 assay showed significant decreases in the viability of MM.1S and RPMI 8226 cells, suggesting that the TMED2 gene plays an important role in the proliferation of these two cell lines. The cell cycle of MM.1S and RPMI 8226 cells was substantially altered by shTMED2, as evidenced by the increased number of cells in G1 phase and decreased number of cells in S and G2/M phases. The FACS analysis revealed a significant increase in the apoptosis of MM.1S and RPMI 8226 cells due to the increased activity of Caspase 3/7, suggesting that the TMED2 gene is significantly related to the apoptosis of these two cell lines.

Conclusion

Based on these results, TMED2 may play an important role in the pathogenesis of MM. This novel study may contribute to further investigations of useful biomarkers and potential therapeutic targets in patients with MM.

Wnt signaling in breast cancer: biological mechanisms, challenges and opportunities

Wnt signaling is a highly conserved signaling pathway that plays a critical role in controlling embryonic and organ development, as well as cancer progression. Genome-wide sequencing and gene expression profile analyses have demonstrated that Wnt signaling is involved mainly in the processes of breast cancer proliferation and metastasis. The most recent studies have indicated that Wnt signaling is also crucial in breast cancer immune microenvironment regulation, stemness maintenance, therapeutic resistance, phenotype shaping, etc. Wnt/β-Catenin, Wnt-planar cell polarity (PCP), and Wnt-Ca2+ signaling are three well-established Wnt signaling pathways that share overlapping components and play different roles in breast cancer progression. In this review, we summarize the main findings concerning the relationship between Wnt signaling and breast cancer and provide an overview of existing mechanisms, challenges, and potential opportunities for advancing the therapy and diagnosis of breast cancer.

Natural Exogenous Antioxidant Defense against Changes in Human Skin Fibroblast Proteome Disturbed by UVA Radiation

Daily exposure of the skin to UVA radiation causes oxidative modifications to cellular components and biomolecules. These include proteins involved in the metabolism and cytoprotection of fibroblasts, and their modification can contribute to the disruption of cell function and the development of skin disorders. Therefore, there remains a need for highly active cytoprotective compounds with antioxidant properties. The purpose of this study was to investigate the effect of ascorbic acid on the activity of rutin against UVA-induced changes in the proteome of human fibroblasts. All analyses were carried out on fibroblasts cultured in a three-dimensional system exposed to UVA radiation and incubated with rutin and ascorbic acid. Their proteomic profile was analyzed using nano-HPLC, which revealed 150 proteins whose expression was significantly altered between treatment conditions. UVA radiation led to changes in the expression of 82 proteins. However, some of these changes were mitigated by rutin and ascorbic acid separately (23 and 25 proteins, respectively) and rutin and ascorbic acid together (23 proteins). UVA radiation has led to the upregulation of proteins involved in gene expression, catalytic processes and antioxidant pathways, and downregulation of proteins with binding activity. Nevertheless, rutin and ascorbic acid used separately or together have countered these changes to varying degrees. Moreover, rutin and ascorbic acid stimulated fibroblasts irradiated by UVA to increase the expression of the signalling molecules responsible for the opening of the transmembrane channels. In the context of the results obtained, the observed cytoprotective effect of the cooperation of rutin and ascorbic acid results not only from the overlapping properties of the compounds. The effect of rutin alone is probably inhibited by its limited bioavailability. Therefore, its interaction with ascorbic acid increases membrane penetration and improves the cytoprotective effect on skin fibroblasts.

Expansion of Single Cell Transcriptomics Data of SARS-CoV Infection in Human Bronchial Epithelial Cells to COVID-19

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 19 (COVID-19) that was emerged as a new member of coronaviruses since December 2019 in Wuhan, China and then after was spread in all continentals. Since SARS-CoV-2 has shown about 77.5% similarity to SARS-CoV, the transcriptome and immunological regulations of SARS-CoV-2 was expected to have high percentage of overlap with SARS-CoV.

Results

In this study, we applied the single cell transcriptomics data of human bronchial epithelial cells (2B4 cell line) infected with SARS-CoV, which was annotated in the Expression Atlas database to expand this data to COVID-19. In addition, we employed system biology methods including gene ontology (GO) and Reactome pathway analyses to define functional genes and pathways in the infected cells with SARS-CoV. The transcriptomics analysis on the Expression Atlas database revealed that most genes from infected 2B4 cell line with SARS-CoV were downregulated leading to immune system hyperactivation, induction of signaling pathways, and consequently a cytokine storm. In addition, GO:0016192 (vesicle-mediated transport), GO:0006886 (intracellular protein transport), and GO:0006888 (ER to Golgi vesicle-mediated transport) were shown as top three GOs in the ontology network of infected cells with SARS-CoV. Meanwhile, R-HAS-6807070 (phosphatase and tensin homolog or PTEN regulation) showed the highest association with other Reactome pathways in the network of infected cells with SARS-CoV. PTEN plays a critical role in the activation of dendritic cells, B- and T-cells, and secretion of proinflammatory cytokines, which cooperates with downregulated genes in the promotion of cytokine storm in the COVID-19 patients.

Conclusions

Based on the high similarity percentage of the transcriptome of SARS-CoV with SARS-CoV-2, the data of immunological regulations, signaling pathways, and proinflammatory cytokines in SARS-CoV infection can be expanded to COVID-19 to have a valid platform for future pharmaceutical and vaccine studies.