Hypertensive Patients Exhibit Enhanced Thrombospondin-1 Levels at High-Altitude

Role of CD93 in Health and Disease

CD93 (also known as complement protein 1 q subcomponent receptor C1qR1 or C1qRp), is a transmembrane glycoprotein encoded by a gene located on 20p11.21 and composed of 652 amino acids. CD93 can be present in two forms: soluble (sCD93) and membrane-bound (CD93). CD93 is mainly expressed on endothelial cells, where it plays a key role in promoting angiogenesis both in physiology and disease, such as age-related macular degeneration and tumor angiogenesis. In fact, CD93 is highly expressed in tumor-associated vessels and its presence correlates with a poor prognosis, poor immunotherapy response, immune cell infiltration and high tumor, node and metastasis (TNM) stage in many cancer types. CD93 is also expressed in hematopoietic stem cells, cytotrophoblast cells, platelets and many immune cells, i.e., monocytes, neutrophils, B cells and natural killer (NK) cells. Accordingly, CD93 is involved in modulating important inflammatory-associated diseases including systemic sclerosis and neuroinflammation. Finally, CD93 plays a role in cardiovascular disease development and progression. In this article, we reviewed the current literature regarding the role of CD93 in modulating angiogenesis, inflammation and tumor growth in order to understand where this glycoprotein could be a potential therapeutic target and could modify the outcome of the abovementioned pathologies.

Diagnostic and Prognostic Role of CD93 in Cardiovascular Disease: A Systematic Review

INTRODUCTION

Cluster of Differentiation (CD) 93 (also known as complement protein 1 q subcomponent receptor C1qR1 or C1qRp) is a transmembrane glycoprotein that can also be present in a soluble (sCD93) form. Recent studies have investigated the role of this protein in cardiovascular disease (CVD). The present systematic review aims to assess the associations between CD93 and cardiovascular (CV) risk factors and disease at both the proteomic and genomic levels.

METHODS

We conducted systematic searches in the PubMed, EMBASE, and Web of Science databases to identify all human studies since inception to February 2023 that investigated the role of CD93 in CV risk factors, CVD, and CV-associated outcomes. The data collection and analysis have been independently conducted by two reviewers. The search terms included: cardiovascular, heart failure, acute stroke, myocardial infarction, stroke, peripheral artery disease, cardiovascular death, MACE, hypertension, metabolic syndrome, hyperuricemia, diabetes, cd93, c1qr, C1qR1, complement protein 1 q subcomponent receptor.

RESULTS

A total of 182 references were identified, and 15 studies investigating the associations between CD93 protein levels or CD93 genetic polymorphisms and the development or prevalence of CV risk factors (i.e., hypertension, dyslipidemia, and obesity) and CVD (i.e., heart failure, coronary artery disease, and ischemic stroke) were included. Although promising, the quality and dimension of the analyzed studies do not allow for a definitive answer to the question of whether CD93 may hold diagnostic and prognostic value in CVD.

Yth m6A RNA-Binding Protein 1 Regulates Osteogenesis of MC3T3-E1 Cells under Hypoxia via Translational Control of Thrombospondin-1

Peri-implantitis is a major factor affecting implant prognosis, and the specific anatomy of the peri-implant area makes it more vulnerable to the local hypoxic environment caused by inflammation. N6-methyladenosine (m⁶A) plays a vital role in a multitude of biological processes, and its main "reader" Yth m⁶A RNA-binding protein 1 (YTHDF1) is suggested to affect osteogenic differentiation. However, the mechanism underlying the effect of YTHDF1 on osteogenic differentiation under hypoxic conditions remains unclear. To address this question, we examined the expression of YTHDF1 under hypoxia and observed that hypoxia suppressed osteogenic differentiation but promoted the expression of YTHDF1. Then we knocked down YTHDF1 and found decreased levels of osteogenic-related markers, alkaline phosphatase (ALP) activity, and alizarin red staining (ARS) under normoxia or hypoxia treatment. Bioinformatics analysis identified Thrombospondin-1 (THBS1) might be a downstream factor of YTHDF1. The results revealed that YTHDF1 enhanced the stability of THBS1 mRNA, and immunofluorescence assays found co-localization with YTHDF1 and THBS1 under hypoxia. Loss of function studies showed knocking down YTHDF1 or THBS1 exacerbated the osteogenic inhibition caused by hypoxia. All data imply that hypoxia suppresses osteogenic differentiation and promotes the expression of YTHDF1, which translationally regulates THBS1 in an m⁶A-dependent manner, potentially counteracting hypoxia-induced osteogenic inhibition through the YTHDF1/THBS1 pathway. The results of this study reveal for the first time the molecular mechanism of the regulation of osteogenic differentiation by YTHDF1 under hypoxia and suggest that YTHDF1, together with its downstream factor THBS1, may be critical targets to counteract osteogenic inhibition under hypoxic conditions, providing promising therapeutic strategy for the hypoxia-induced bone loss in peri-implantitis.