Modulation of Adhesion Molecules Expression by Different Metalloproteases Isolated from Bothrops Snakes

Snake venom metalloproteinases (SVMP) are involved in local inflammatory reactions observed after snakebites. Based on domain composition, they are classified as PI (pro-domain + proteolytic domain), PII (PI + disintegrin-like domains), or PIII (PII + cysteine-rich domains). Here, we studied the role of different SVMPs domains in inducing the expression of adhesion molecules at the microcirculation of the cremaster muscle of mice. We used Jararhagin (Jar)—a PIII SVMP with intense hemorrhagic activity, and Jar-C—a Jar devoid of the catalytic domain, with no hemorrhagic activity, both isolated from B. jararaca venom and BnP-1—a weakly hemorrhagic P1 SVMP from B. neuwiedi venom. Toxins (0.5 µg) or PBS (100 µL) were injected into the scrotum of mice, and 2, 4, or 24 h later, the protein and gene expression of CD54 and CD31 in the endothelium, and integrins (CD11a and CD11b), expressed in leukocytes were evaluated. Toxins induced significant increases in CD54, CD11a, and CD11b at the initial time and a time-related increase in CD31 expression. In conclusion, our results suggest that, despite differences in hemorrhagic activities and domain composition of the SVMPs used in this study, they behave similarly to the induction of expression of adhesion molecules that promote leukocyte recruitment.

Diagnostic Values of Dermatoscopy and CD31 Expression in Cutaneous Lymphangioma Circumscriptum

Background: Cutaneous lymphangioma circumscriptum is characterized by clusters of deep-seated, vesicle-like papules. Cutaneous lymphangioma circumscriptum (CLC) is not a tumor but rather a congenital malformation of superficial lymphatics.Objectives: The study aimed to describe the dermoscopic features of CLC and investigate the reason why marked blood components in CLC. Moreover, this study sought to increase awareness of the clinical characteristics of CLC and provide insights into CLC diagnosis.Methods: A representative sample of patients with CLC with demographic information and pathological and dermoscopical results was analyzed. The immunohistochemistry of lymphangioma specimens with CD31 and D2-40 was performed. The clinical manifestations of CLC, demographic information, and the results of immunohistochemistry were statistically analyzed to validate the correlation.Results: Besides the pattern of frog spawn-like blisters, lymphangioma also presented as either transparent or pigmented with dark-red to whitish/yellowish shades. Moreover, lymphangioma manifested as a pattern of dermatofibroma. Furthermore, CD31 was detected in the flattened endothelium and only present in dilated spaces containing enough blood or lymph components.Limitations: This study is limited by its retrospective nature and statistical power.Conclusion: Dermoscopy is useful for the diagnosis of CLC. CD31 positive staining and cystic-dilated spaces showed flattened inner and outer endothelia are the diagnostic features in hypopyon-like shape and blisters resembling frog spawn patterns in CLC. These features can assist in the diagnosis of CLC.

Competition between distinct ApoE alleles and mCRP for the endothelial receptor CD31 differentially regulates neurovascular inflammation and Alzheimer's disease pathology

BACKGROUND: C-reactive protein (CRP) in peripheral inflammation is associated with increased Alzheimer disease (AD) risk in Apolipoprotein E4 (ApoE4), but not ApoE3 or E2, humans. It remains unknown whether peripheral monomeric CRP (mCRP) induces AD pathogenesis through some receptor of blood-facing endothelia in the brain in an ApoE genotype dependent fashion. METHODS: We used human samples, ApoE knock-in and deficient mouse models, and primary brain endothelia. Different ApoE mice were intraperitoneally (i.p.) injected with mCRP. The characterizations by immunostaining, proximity ligation assay (PLA) and siRNA were conducted to identify the receptor for mCRP. Brain microvessel and endothelia were isolated for RNA sequencing to explore the molecular pathway. RESULTS: We demonstrate that CD31 (PECAM-1), a blood-facing endothelial receptor in brain, is a competitive target of both mCRP and ApoE protein. ApoE2 competes more strongly with mCRP for CD31 than ApoE4 does, and expressing ApoE4 or knocking out ApoE gene results in higher levels of mCRP-CD31 binding, leading to a decrease of CD31 expression but an increase in CD31 phosphorylation, along with greater cerebrovascular damage and AD pathology. This competitive binding mediates differential endothelial molecular responses depending on ApoE genotype, increasing cerebrovascular inflammation and mitochondria impairment in ApoE4 mice, while inducing vasculogenesis and protective changes in the presence of ApoE2. CONCLUSIONS: Our study reveals a novel and dynamic endothelial ApoE-mCRP-CD31 pathway for AD pathogenesis during chronic inflammation and provides some insight into the opposing ApoE4-neurodegenerative and ApoE2-neuroprotective effects in AD.

Expression Profiles of VEGF-A, CD31 and GRP78 in Non-Small Cell Lung Cancer.

BackgroundAngiogenesis is mandatory for tumor growth and progression. The modest response to the anti-angiogenic therapies in non-small cell lung cancer reflects the presence of confounding molecular factors. The aims of this study were to investigate the expression levels of VEGF-A, CD31 and GRP78 and test for significant correlations between them.MethodsParaffin-embedded NSCLC tissue samples (71 adenocarcinoma and 23 squamous cell carcinoma) were retrospectively collected from 94 patients who underwent surgical resection between 2008 and 2015; and did not receive chemotherapy or radiotherapy prior to surgery. The expressions of VEGF-A, CD31 and GRP78 were determined by immunohistochemistry. ResultsHigh expression levels of VEGF-A, CD31 and GRP78 were observed in 15, 36 and 74 cases, respectively. Adenocarcinomas expressed higher levels of the aforementioned proteins as compared with squamous cell carcinomas (p-value < 0.05). Moreover, a statistically significant association was found between VEGF-A and CD31 expression levels (p-value = 0.006).ConclusionsOur study was the first to investigate the associations between GRP78 and the angiogenesis markers CD31 and VEGF-A in NSCLC patients. High GRP78 expression was revealed in the majority of the investigated samples. Nevertheless, no relationship was found between GRP78 and VEGF-A or CD31 which could be attributed to small sample size. On the other hand, the positive association between VEGF-A and CD31 expression levels suggests that VEGF-A may cooperate with CD31 to promote angiogenesis in NSCLC.

Rapid endothelial infection, endothelialitis and vascular damage characterise SARS-CoV-2 infection in a human lung-on-chip model

Severe cases of COVID-19 present with hypercoagulopathies and systemic endothelialitis of the lung microvasculature. The dynamics of vascular damage, and whether it is a direct consequence of endothelial infection or an indirect consequence of immune cell mediated cytokine storms is unknown. This is in part because in vitro models are typically epithelial cell monocultures or fail to recapitulate vascular physiology. We use a vascularised lung-on-chip model where, consistent with monoculture reports, low numbers of SARS-CoV-2 virions are released apically from alveolar epithelial cells. However, rapid infection of the underlying endothelial layer leads to the generation of clusters of endothelial cells with low or no CD31 expression, a progressive loss of endothelial barrier integrity, and a pro-coagulatory microenvironment. These morphological changes do not occur if these cells are exposed to the virus apically. Viral RNA persists in individual cells, which generates a response that is skewed towards NF-KB mediated inflammation, is typified by IL-6 secretion even in the absence of immune cells, and is transient in epithelial cells but persistent in endothelial cells. Perfusion with Tocilizumab, an inhibitor of trans IL-6 signalling slows the loss of barrier integrity but does not prevent the formation of endothelial cell clusters with reduced CD31 expression. SARS-CoV-2 mediated endothelial cell damage occurs despite a lack of rapid viral replication, in a cell-type specific manner and independently of immune-cell mediated cytokine storms, whose effect would only exacerbate the damage.

A Dual-Targeting Ruthenium Nanodrug that Inhibits Primary Tumor Growth and Lung Metastasis by the PARP/ATM Pathway

Many studies have found that ruthenium complexes have unique biochemical characteristics and thus inhibit tumor growth or metastasis. Our aim was to report a novel dual-targeting ruthenium candidate 2b with both antitumor and antimetastatic functions that could target tumor sites using both EPR effects and TF/TFR. It was composed of ruthenium-complexed carboline acid and four chloride ions. In vitro, 2b could trigger DNA cleavage and thus block the cell cycle and cause apoptosis by the PARP/ATM pathway. In vivo, 2b could inhibit not only LLC tumor growth but also lung metastasis. We found apoptosis and decrease in CD31 expression in tumor tissue. In addition, we also found that 2b could collect in tumor tissue. Thus, we concluded that 2b could target tumors, inhibit tumor growth and prevent lung metastasis.

CD31 as a Therapeutic Target in Atherosclerosis

The potential of CD31 as a therapeutic target in atherosclerosis has been considered ever since its cloning in the 1990s, but the exact role played by this molecule in the biologic events underlying atherosclerosis has remained controversial, resulting in the stalling of any therapeutic perspective. Due to the supposed cell adhesive properties of CD31, specific monoclonal antibodies and recombinant proteins were regarded as blocking agents because their use prevented the arrival of leukocytes at sites of acute inflammation. However, the observed effect of those compounds likely resulted from the engagement of the immunomodulatory function of CD31 signaling. This was acknowledged only later though, upon the discovery of CD31’s 2 intracytoplasmic tyrosine residues called immunoreceptor tyrosine inhibitory motifs. A growing body of evidence currently points at a therapeutic potential for CD31 agonists in atherothrombosis. Clinical observations show that CD31 expression is altered at the surface of leukocytes infiltrating unhealed atherothrombotic lesions and that the physiological immunomodulatory functions of CD31 are lost at the surface of blood leukocytes in patients with acute coronary syndromes. On the contrary, translational studies using candidate therapeutic molecules in laboratory animals have provided encouraging results: synthetic peptides administered to atherosclerotic mice as systemic drugs in the acute phases of atherosclerotic complications favor the healing of wounded arteries, whereas the immobilization of CD31 agonist peptides onto coronary stents implanted in farm pigs favors their peaceful integration within the coronary arterial wall.

Club cell protein 16 in sera from trauma patients modulates neutrophil migration and functionality via CXCR1 and CXCR2

Background Club Cell protein (CC)16 correlates with lung injury and respiratory complications, which are in part triggered by polymorphonuclear leukocytes (PMNL) in severely traumatized patients (TP). CC16 exerts anti-inflammatory and immunosuppressive effects, however, its influence on PMNL functions after trauma is unknown. Here, we evaluated whether CC16 present in sera from TP could modify the biological functions of PMNL. Methods Sera from 16 severely injured TP without pneumonia (no P, n = 8) or with pneumonia (P, n = 8) were collected at admission to emergency department (ED) and 1 day prior pneumonia and pre-incubated with or without anti-CC16 antibody for CC16 neutralization. Samples from the equal post-injury days in the corresponding no P group were used. Neutrophils were isolated from healthy volunteers (HV, n = 5) and incubated with 20% of the serum medium from TP, respectively. In PMNL, CD62L, CD11b/CD18 and CD31 expression, migratory capacity, phagocytosis rate, oxidative burst and apoptosis were investigated. In isolated PMNL, CXCR1 and CXCR2 were neutralized before stimulation with CC16, and oxidative burst, phagocytosis and apoptosis were analyzed in neutrophils and their subsets. Results Serum from the P group enhanced significantly PMNL migration compared to no P group, while CC16-neutralization further increased the migratory rate of PMNL in both groups. CC16-neutralization increased significantly the expression of CD62L in the P group at ED. Oxidative burst was significantly increased in the P group vs. no P during the study period. CC16 seemed to have no influence on oxidative burst and phagocytosis in TP. However, in a more controlled study design, CC16 induced a significant increase of oxidative burst and a decrease of apoptosis of CD16+ granulocytes. These effects were markedly observed in mature CD16brightCD62Lbright and immune suppressive CD16brightCD62Ldim neutrophils. In mature subset, CXCR1 and CXCR2 neutralization diminished CC16-induced effects. Conclusions CC16 in sera from multiply traumatized patients, notably of those with pneumonia, has significant effects on PMNL. The results suggest an association of CC16 with CXCR1 and CXCR2. Our data suggest that CC16 reduces the migratory capacity of PMNL and thus modulates their function in patients with respiratory complications after trauma.