The Role of a Lung Vascular Endothelium Enriched Gene TMEM100

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.

Detection of transmembrane protein 100 in breast cancer: Correlation with malignant progression and chemosensitivity

Objective

With increased incidence, breast cancer has become the most common malignant tumor in women. Transmembrane protein 100 (TMEM100) is a key factor affecting the progression of malignant tumors. The aim of the study is to examine the molecular mechanism of TMEM100 in malignant progression.

Material and Methods

TMEM100 expression was analyzed by Western blot, immunohistochemistry, and real-time quantitative polymerase chain reaction. Cell migration and invasiveness after transfection with TMEM100 were investigated by Transwell assay. 5-ethynyl-2-deoxyuridine staining and cell colony-formation assay were utilized to the exploration of cell proliferation. Flow cytometry was adopted to detect whether TMEM100 affected the effect of Docetaxel on cell apoptosis. The effects of TMEM100 on the Ras-extracellular signal-regulated kinase (RAS/ERK) pathway were explored by Western blot assay.

Results

Downregulated TMEM100 expression was in breast cancer tissues (P < 0.01). TMEM100 overexpression hindered the invasion (P < 0.01), migration (P < 0.01), and proliferation (P < 0.01) of breast cancer cells. Chemotherapy sensitivity of breast cancer cells to docetaxel was enhanced by TMEM100 (P < 0.01). TMEM100 inhibited Ras expression and ERK1/2 phosphorylation (P < 0.01). Furthermore, ERK agonist TertButylhydroquinone neutralized the effects of TMEM100 (P < 0.01).

Conclusion

TMEM100 blocked malignant progression of breast cancer and enhanced docetaxel chemosensitivity by suppressing RAS/ERK pathway. These data manifested that regulation of TMEM100 expression may affect the progression of breast cancer, and its prognostic value and mechanism deserve further investigation.

SARS-CoV-2 infection results in a unique lung proteome long after virus resolution in the hamster

Long COVID or post-acute sequelae of COVID-19 (PASC) remains an ongoing public health issue that causes impairment for those afflicted and diminishes their ability to contribute to society. To address the host response underpinning respiratory PASC, we used the Golden Syrian hamster model infected with ancestral SARS-CoV-2 and examined its lung proteome in a longitudinal experiment. We infected young 6-week old male and female hamsters with 105 TCID50 of virus via the intranasal route and sampled the lung at 1, 3, 5, and 31 days post infection (dpi). We compared the infected lung proteome to that of uninfected sex-matched controls. We found almost no differences in protein levels at 1 dpi, with hundreds at 3 dpi, and thousands at 5 dpi. Many overlapping differential protein levels and pathways were seen in both sexes at 3 and 5 dpi including the Coagulation and Complement cascades. Notably, we found differences between the sexes at 31 dpi which included many targets with decreased levels of protein in the males. We also noted an increase in 7 proteins in both sexes at 31 dpi including proteins responsible for airway mucosal layer integrity such as Mucin 5B and Calcium-activated chloride channel regulator 1. Longitudinally, 38 proteins were changed in levels across more than one timepoint in the males but only three proteins were in the females, Secretoglobin family 1 A member 1, Poly [ADP-ribose] polymerase, and Apolipoprotein D. Overall, we show that there are changes to the lung proteome at 31 dpi, a time when no SARS-CoV-2 remains, and that there are sex differences in that proteome after infection with the ancestral strain. We conclude that biological sex should be examined as a variable when testing medical countermeasures for PASC in the Golden Syrian hamster due to host differences between the sexes.

A Novel Animal Model for Pulmonary Hypertension: Lung Endothelial-Specific Deletion of Egln1 in Mice

Pulmonary arterial hypertension (PAH) is a devastating disease characterized by high blood pressure in the pulmonary arteries, which can potentially lead to heart failure over time. Previously, our lab found that endothelia-specific knockout of Egln1, encoding prolyl 4-hydroxylase-2 (PHD2), induced spontaneous pulmonary hypertension (PH). Recently, we elucidated that Tmem100 is a lung-specific endothelial gene using Tmem100-CreERT2 mice. We hypothesize that lung endothelial-specific deletion of Egln1 could lead to the development of PH without affecting Egln1 gene expression in other organs. Tmem100-CreERT2 mice were crossed with Egln1 flox/flox mice to generate Egln1 f/f ;Tmem100-CreERT2 (LiCKO) mice. Western blot and immunofluorescent staining were performed to verify the knockout efficacy of Egln1 in multiple organs of LiCKO mice. PH phenotypes, including hemodynamics, right heart size and function, pulmonary vascular remodeling, were evaluated by right heart catheterization and echocardiography measurements. Tamoxifen treatment induced Egln1 deletion in the lung endothelial cells (ECs) but not in other organs of adult LiCKO mice. LiCKO mice exhibited an increase in right ventricular systolic pressure (RVSP, ~35 mmHg) and right heart hypertrophy. Echocardiography measurements showed right heart hypertrophy, as well as cardiac and pulmonary arterial dysfunction. Pulmonary vascular remodeling, including increased pulmonary wall thickness and muscularization of distal pulmonary arterials, was enhanced in LiCKO mice compared to wild-type mice. Tmem100 promoter-mediated lung endothelial knockout of Egln1 in mice leads to development of spontaneous PH. LiCKO mice could serve as a novel mouse model for PH to study lung and other organ crosstalk.

System biology approach to identify the novel biomarkers in glioblastoma multiforme tumors by using computational analysis

Introduction: The most common primary brain tumor in adults is glioblastoma multiforme (GBM), accounting for 45.2% of all cases. The characteristics of GBM, a highly aggressive brain tumor, include rapid cell division and a propensity for necrosis. Regretfully, the prognosis is extremely poor, with only 5.5% of patients surviving after diagnosis. Methodology: To eradicate these kinds of complicated diseases, significant focus is placed on developing more effective drugs and pinpointing precise pharmacological targets. Finding appropriate biomarkers for drug discovery entails considering a variety of factors, including illness states, gene expression levels, and interactions between proteins. Using statistical techniques like p-values and false discovery rates, we identified differentially expressed genes (DEGs) as the first step in our research for identifying promising biomarkers in GBM. Of the 132 genes, 13 showed upregulation, and only 29 showed unique downregulation. No statistically significant changes in the expression of the remaining genes were observed. Results: Matrix metallopeptidase 9 (MMP9) had the greatest degree in the hub biomarker gene identification, followed by (periostin (POSTN) at 11 and Hes family BHLH transcription factor 5 (HES5) at 9. The significance of the identification of each hub biomarker gene in the initiation and advancement of glioblastoma multiforme was brought to light by the survival analysis. Many of these genes participate in signaling networks and function in extracellular areas, as demonstrated by the enrichment analysis.We also identified the transcription factors and kinases that control proteins in the proteinprotein interactions (PPIs) of the DEGs. Discussion: We discovered drugs connected to every hub biomarker. It is an appealing therapeutic target for inhibiting MMP9 involved in GBM. Molecular docking investigations indicated that the chosen complexes (carmustine, lomustine, marimastat, and temozolomide) had high binding affinities of -6.3, -7.4, -7.7, and -8.7 kcal/mol, respectively, the mean root-mean-square deviation (RMSD) value for the carmustine complex and marimastat complex was 4.2 Å and 4.9 Å, respectively, and the lomustine and temozolomide complex system showed an average RMSD of 1.2 Å and 1.6 Å, respectively. Additionally, high stability in root-mean-square fluctuation (RMSF) analysis was observed with no structural conformational changes among the atomic molecules. Thus, these in silico investigations develop a new way for experimentalists to target lethal diseases in future.

Diminished TMEM100 Expression in a Newborn With Acinar Dysplasia and a Novel TBX4 Variant: A Case Report

Acinar dysplasia (AcDys) of the lung is a rare lethal developmental disorder in neonates characterized by severe respiratory failure and pulmonary arterial hypertension refractory to treatment. Recently, abnormalities of TBX4-FGF10-FGFR2-TMEM100 signaling regulating lung development have been reported in patients with AcDys due to heterozygous single-nucleotide variants or copy-number variant deletions involving TBX4, FGF10, or FGFR2. Here, we describe a female neonate who died at 4 hours of life due to severe respiratory distress related to AcDys diagnosed by postmortem histopathologic evaluation. Genomic analyses revealed a novel deleterious heterozygous missense variant c.728A>C (p.Asn243Thr) in TBX4 that arose de novo on paternal chromosome 17. We also identified 6 candidate hypomorphic rare variants in the TBX4 enhancer in trans to TBX4 coding variant. Gene expression analyses of proband's lung tissue showed a significant reduction of TMEM100 expression with near absence of TMEM100 within the endothelium of arteries and capillaries by immunohistochemistry. These results support the pathogenicity of the detected TBX4 variant and provide further evidence that disrupted signaling between TBX4 and TMEM100 may contribute to severe lung phenotypes in humans, including AcDys.

Pulmonary Hypertension in Developmental Lung Diseases

Diverse genetic developmental lung diseases can present in the neonatal period with hypoxemic respiratory failure, often associated with with pulmonary hypertension. Intractable hypoxemia and lack of sustained response to medical management should increase the suspicion of a developmental lung disorder. Genetic diagnosis and lung biopsy are helpful in establishing the diagnosis. Early diagnosis can result in optimizing management and redirecting care if needed. This article reviews normal lung development, various developmental lung disorders that can result from genetic abnormalities at each stage of lung development, their clinical presentation, management, prognosis, and differential diagnoses.