Distinct RNA transcriptome patterns are potentially associated with angiogenesis in Tie2-expressing monocytes

Identification and in silico characterization of structural and functional impacts of genetic variants in milk protein genes in the Zebu breeds Guzerat and Gyr

Whole genome sequencing of bovine breeds has allowed identification of genetic variants in milk protein genes. However, functional repercussion of such variants at a molecular level has seldom been investigated. Here, the results of a multistep Bioinformatic analysis for functional characterization of recently identified genetic variants in Brazilian Gyr and Guzerat breeds is described, including predicted effects on the following: (i) evolutionary conserved nucleotide positions/regions; (ii) protein function, stability, and interactions; (iii) splicing, branching, and miRNA binding sites; (iv) promoters and transcription factor binding sites; and (v) collocation with QTL. Seventy-one genetic variants were identified in the caseins (CSN1S1, CSN2, CSN1S2, and CSN3), LALBA, LGB, and LTF genes. Eleven potentially regulatory variants and two missense mutations were identified. LALBA Ile60Val was predicted to affect protein stability and flexibility, by reducing the number the disulfide bonds established. LTF Thr546Asn is predicted to generate steric clashes, which could mildly affect iron coordination. In addition, LALBA Ile60Val and LTF Thr546Asn affect exonic splicing enhancers and silencers. Consequently, both mutations have the potential of affecting immune response at individual level, not only in the mammary gland. Although laborious, this multistep procedure for classifying variants allowed the identification of potentially functional variants for milk protein genes.

The lnc-CTSLP8 upregulates CTSL1 as a competitive endogenous RNA and promotes ovarian cancer metastasis

Background

Ovarian cancer is highly lethal and has a poor prognosis due to metastasis. Long non-coding RNAs (lncRNAs) are key regulators of tumor development, but their role in ovarian cancer metastasis remains unclear.

Methods

The expression of lnc-CTSLP8 in ovarian cancer was analyzed in public databases (TCGA and GEO) and validated via qRT-PCR. Lnc-CTSLP8 overexpression and knockout cell lines were constructed using a lentiviral vector and the CRISP/Cas9 system. Cell proliferation, colony formation, migration, and invasion were analyzed. An ovarian orthotopic tumor mouse model was used for the in vivo study. Changes in autophagosomes, autolysosomes, and mitochondria in ovarian cancer cells were observed via transmission electron microscopy. EMT markers were detected by immunoblotting and immunofluorescence assays. RNA immunoprecipitation, RNA pull-down, and dual luciferase reporter assays were performed to confirm the interaction between lnc-CTSLP8 and miR-199a-5p.

Results

A novel pseudogene, lnc-CTSLP8, was identified in ovarian cancer, with significantly elevated expression in metastatic tumor tissues compared to primary ovarian tumors. When overexpressed, lnc-CTSLP8 promoted ovarian cancer in vitro and in vivo by acting as a sponge for miR-199a-5p. Autophagy and EMT in ovarian cancer were also enhanced by lnc-CTSLP8. Mechanistically, lnc-CTSLP8 upregulated CTSL1 as a competitive endogenous RNA and exhibited oncogenic effects. Moreover, CTSL1 inhibitor treatment and miR-199a-5p overexpression abrogated the effects of lnc-CTSLP8 overexpression.

Conclusions

lnc-CTSLP8 acts as a ceRNA in ovarian cancer and represents a potential therapeutic target for metastatic ovarian cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01957-z.

Non-Coding RNAs and Hereditary Hemorrhagic Telangiectasia

Non-coding RNAs (ncRNAs) are functional ribonucleic acid (RNA) species that include microRNAs (miRs), a class of short non-coding RNAs (∼21–25 nucleotides), and long non-coding RNAs (lncRNAs) consisting of more than 200 nucleotides. They regulate gene expression post-transcriptionally and are involved in a wide range of pathophysiological processes. Hereditary hemorrhagic telangiectasia (HHT) is a rare disorder inherited in an autosomal dominant fashion characterized by vascular dysplasia. Patients can develop life-threatening vascular malformations and experience severe hemorrhaging. Effective pharmacological therapies are limited. The study of ncRNAs in HHT is an emerging field with great promise. This review will explore the current literature on the involvement of ncRNAs in HHT as diagnostic and pathogenic factors.

Decreased levels of miR-28-5p and miR-361-3p and increased levels of insulin-like growth factor 1 mRNA in mononuclear cells from patients with hereditary hemorrhagic telangiectasia 1

Hereditary hemorrhagic telangiectasia (HHT) is a rare vascular disorder inherited in an autosomal dominant manner. Patients with HHT can develop vascular dysplasias called telangiectasias and arteriovenous malformations (AVMs). Our objective was to profile and characterize micro-RNAs (miRNAs), short noncoding RNAs that regulate gene expression posttranscriptionally, in HHT patient-derived peripheral blood mononuclear cells (PBMCs). PBMCs, comprised mostly of lymphocytes and monocytes, have been reported to be dysfunctional in HHT. A total of 40 clinically confirmed HHT patients and 22 controls were enrolled in this study. PBMCs were isolated from 16 mL of peripheral blood and purified for total RNA. MiRNA expression profiling was conducted with a human miRNA array analysis. Select dysregulated miRNAs and miRNA targets were validated with reverse transcription-quantitative polymerase chain reaction. Of the 377 miRNAs screened, 41 dysregulated miRNAs were identified. Both miR-28-5p and miR-361-3p, known to target insulin-like growth factor 1 (IGF1), a potent angiogenic growth factor, were found to be significantly downregulated in HHT patients. Consequently, IGF1 mRNA levels were found to be significantly elevated. Our research successfully identified miRNA dysregulation and elevated IGF1 mRNA levels in PBMCs from HHT patients. This novel discovery represents a potential pathogenic mechanism that could be targeted to alleviate clinical manifestations of HHT.

High circulating angiopoietin-2 levels exacerbate pulmonary inflammation but not vascular leak or mortality in endotoxin-induced lung injury in mice

Background

Elevated plasma levels of angiopoietin-2 (ANGPT2) have been reported in patients with acute lung injury (ALI); however, it remains unclear whether this increase contributes to, or just marks, the underlying vasculopathic inflammation and leak associated with ALI. Here we investigated the biological consequences of inducing high circulating levels of ANGPT2 in a mouse model of endotoxin-induced ALI.

Methods

Transgenic mice (ANGPT2^OVR) with elevated circulating levels of ANGPT2, achieved through conditional hepatocyte-specific overexpression, were examined from 3 to 72 hours following lipopolysaccharide (LPS)-induced ALI. An aptamer-based inhibitor was used to neutralise the effects of circulating ANGPT2 in LPS-exposed ANGPT2^OVR mice.

Results

Total cells, neutrophils and macrophages, as well as inflammatory cytokines, were significantly higher in bronchoalveolar lavage (BAL) of ANGPT2^OVR versus littermate control^tTA mice at 48 hours and 6 hours post-LPS, respectively. In contrast, LPS-induced vascular leak, evidenced by total BAL protein levels and lung wet/dry ratio, was unchanged between ANGPT2^OVR and controls^tTA, while BAL levels of IgM and albumin were decreased in ANGPT2^OVR mice between 24 hours and 48 hours suggesting a partial attenuation of vascular leak. There was no significant difference in LPS-induced mortality between ANGPT2^OVR and controls^tTA. An ANGPT2-neutralising aptamer partially attenuated alveolar cell infiltration while exacerbating vascular leak in LPS-exposed ANGPT2^OVR mice, supported by underlying time-dependent changes in the lung transcriptional profiles of multiple genes linked to neutrophil recruitment/adhesion and endothelial integrity.

Conclusions

Our findings suggest that high circulating ANGPT2 potentiates endotoxin-induced lung inflammation but may also exert other pleiotropic effects to help fine-tune the vascular response to lung injury.

Crosstalk between TEMs and endothelial cells modulates angiogenesis and metastasis via IGF1-IGF1R signalling in epithelial ovarian cancer

BACKGROUND

Epithelial ovarian cancer (EOC) is the leading cause of death from gynaecologic malignancies and has a poor prognosis due to metastasis. Drugs targeting the angiogenesis pathway significantly improve patient outcome. However, the key factors linking angiogenesis and metastasis have not been elucidated. In this study, we found Tie2 expressing monocytes (CD14⁺Tie2⁺, TEMs) as key contributors to angiogenesis and metastasis of EOC.

METHODS

Tissue slides were evaluated by immunofluorescence for the presence of total tissue macrophages and TEMs. The correlation between microvascular density (MVD) values and the TEMs number or ratio was calculated in both ovarian cancer tissues and peritoneum. The rate of TEMs in monocytes was evaluated in the peripheral blood of female healthy donors, benign cysts patients, and EOC patients using flow cytometry. The TEMs rate in ascites from EOC patients was also evaluated by flow cytometry. The concentration of Ang2, as the ligand of Tie2, was examined by ELISA in serum samples of EOC patients, benign cysts patients, and ascites samples of EOC patients. The effects of Ang2 on the migration and the cytokine expression of TEMs were further examined. The pro- angiogenesis activity of TEMs via IGF1 was performed in both in vivo and in vitro. And the IGF1 blocking test was performed using neutralising antibody.

RESULTS

TEMs were significantly higher in tumour foci, peripheral blood and ascites in EOC patients. The proportion of TEMs among total tissue macrophages was positively correlated with tumour MVD. In vivo animal results showed that TEMs promoted EOC angiogenesis and metastasis. Further functional and mechanisms studies revealed that concentration of angiopoietin 2 (Ang2), a ligand of Tie2, was elevated in EOC ascites which further recruit TEMs in a dose-dependent manner as a powerful chemokine to TEMs. Recruited TEMs promoted endothelial cell function through IGF1-activated downstream signalling. Blocking secreted IGF1 using inhibiting antibody reduced TEMs mediated angiogenesis and metastasis.

CONCLUSIONS

TEMs significantly increased in EOC patients and were recruited to tumour loci by the increased Ang2. The increased TEMs have diagnostic value in ovarian cancer and were positively correlated with the MVD in ovarian cancer tissue. Furthermore, TEMs promote angiogenesis via IGF1 in both in vivo and in vitro experimental systems after stimulation by Ang2. Altogether, this study paves the way to develop novel therapy targets as the axis of Ang2-TEMs-IGF1 in EOC.

Human Tumor-Infiltrating Myeloid Cells: Phenotypic and Functional Diversity

Our current understanding of human tumor-resident myeloid cells is, for the most part, based on a large body of work in murine models or studies enumerating myeloid cells in patient tumor samples using immunohistochemistry (IHC). This has led to the establishment of the theory that, by and large, tumor-resident myeloid cells are either “protumor” M2 macrophages or myeloid-derived suppressor cells (MDSC). This concept has accelerated our understanding of myeloid cells in tumor progression and enabled the elucidation of many key regulatory mechanisms involved in cell recruitment, polarization, and activation. On the other hand, this paradigm does not embrace the complexity of the tumor-resident myeloid cell phenotype (IHC can only measure 1 or 2 markers per sample) and their possible divergent function in the hostile tumor microenvironment. Here, we examine the criteria that define human tumor-infiltrating myeloid cell subsets and provide a comprehensive and critical review of human myeloid cell nomenclature in cancer. We also highlight new evidence characterizing their contribution to cancer pathogenesis based on evidence derived from clinical studies drawing comparisons with murine studies where necessary. We then review the mechanisms in which myeloid cells are regulated by tumors in humans and how these are being targeted therapeutically.