Gender differences and pharmacological regulation of angiogenesis induced by synovial fluids in inflammatory arthritis

Association of Neurotrophic Factors at Midlife With In Vivo Measures of β-Amyloid and Tau Burden 15 Years Later in Dementia-Free Adults

BACKGROUND AND OBJECTIVES

Neurotrophic factors (NTFs) play an important role in Alzheimer disease (AD) pathophysiology. Brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) are important NTFs. However, a direct link of BDNF and VEGF circulating levels with in vivo measures of amyloid-β (Aβ) and tau burden remains to be elucidated. We explored the relationship of BDNF and VEGF serum levels with future brain Aβ and tau pathology in a cohort of cognitively healthy, predominantly middle-aged adults and tested for possible effect modifications by sex and menopausal status.

METHODS

This cross-sectional analysis was conducted using data from the Framingham Heart Study (FHS), a community-based cohort study. The study sample included cognitively healthy participants from the FHS Offspring and Third-generation cohorts. BDNF and VEGF were measured in the third-generation cohort during examination cycles 2 (2005-2008) and 1 (2002-2005), respectively, and in the offspring cohort during examination cycle 7 (1998-2001). Participants underwent 11C-Pittsburgh compound B amyloid and 18F-Flortaucipir tau-PET imaging (2015-2021). Linear regression models were used to assess the relationship of serum BDNF and VEGF levels with regional tau and global Aβ, adjusting for potential confounders. Interactions with sex and menopausal status were additionally tested.

RESULTS

The sample included 414 individuals (mean age = 41 ± 9 years; 51% female). Continuous measures of BDNF and VEGF were associated with tau signal in the rhinal region after adjustment for potential confounders (β = -0.15 ± 0.06, p = 0.018 and β = -0.19 ± 0.09, p = 0.043, respectively). High BDNF (≥32,450 pg/mL) and VEGF (≥488 pg/mL) levels were significantly related to lower rhinal tau (β = -0.27 ± 0.11, p = 0.016 and β = -0.40 ± 0.14, p = 0.004, respectively) and inferior temporal tau (β = -0.24 ± 0.11, p = 0.028 and β = -0.26 ± 0.13, p = 0.049, respectively). The BDNF-rhinal tau association was observed only among male individuals. Overall, BDNF and VEGF were not associated with global amyloid; however, high VEGF levels were associated with lower amyloid burden in postmenopausal women (β = -1.96 ± 0.70, p = 0.013, per 1 pg/mL).

DISCUSSION

This study demonstrates a robust association between BDNF and VEGF serum levels with in vivo measures of tau almost 2 decades later. These findings add to mounting evidence from preclinical studies suggesting a role of NTFs as valuable blood biomarkers for AD risk prediction.

The antiangiogenic effect of digitoxin is dependent on a ROS-elicited RhoA/ROCK pathway activation

We previously showed that digitoxin inhibits angiogenesis and cancer cell proliferation and migration and these effects were associated to protein tyrosine kinase 2 (FAK) inhibition. Considering the interactions between FAK and Rho GTPases regulating cell cytoskeleton and movement, we investigated the involvement of RhoA and Rac1 in the antiangiogenic effect of digitoxin. Phalloidin staining of human umbilical vein endothelial cells (HUVECs) showed the formation of stress fibers in cells treated with 10 nM digitoxin. By Rhotekin- and Pak1- pull down assays, detecting the GTP-bound form of GTPases, we observed that digitoxin (10-25 nM) induced sustained (0.5-6 h) RhoA activation with no effect on Rac1. Furthermore, inhibition of HUVEC migration and capillary-like tube formation by digitoxin was counteracted by hindering RhoA-ROCK axis with RhoA silencing or Y-27632 treatment. Digitoxin did not decrease p190RhoGAP phosphorylation at Tyr1105 (a site targeted by FAK), suggesting that RhoA activation was independent from FAK inhibition. Because increasing evidence points to a redox regulation of RhoA, we measured intracellular ROS and found that digitoxin treatment enhanced ROS levels in a concentration-dependent manner (1-25 nM). Notably, the flavoprotein inhibitor DPI or the pan-NADPH oxidase (NOX) inhibitor VAS-2870 antagonized both ROS increase and RhoA activation by digitoxin. Our results provide evidence that inhibition of HUVEC migration and tube formation by digitoxin is dependent on ROS production by endothelial NOX, which leads to the activation of RhoA/ROCK pathway. Digitoxin effects on proteins regulating cytoskeletal organization and cell motility could have a wider impact on cancer progression, beyond the antiangiogenic activity.

Examining the functions of the vascular endothelial growth factor/hypoxia-inducible factor signaling pathway in psoriatic arthritis

Objectives

The present study aimed to examine the roles of the vascular endothelial growth factor (VEGF), hypoxia-inducible factor (HIF), and heme oxygenase-1 (HO-1) in psoriatic arthritis (PsA).

Patients and methods

In this cross-sectional study conducted between November 2020 and May 2021, 64 patients (43 female, 21 male; mean age: 43.2±10.4 years; range, 22 to 60 years) with active PsA were included in the patient group, and 64 healthy volunteers (43 female, 21 male; mean age: 42.8±10.5 years; range, 23 to 61 years) were included in the control group. The demographic features of all cases were recorded. The following indices were used to assess the activity of PsA: Bath Ankylosing Spondylitis Disease Activity Index, Disease Activity Score in 28 joints (DAS28), and Visual Analog Scale. Additionally, Disease Activity in Psoriatic Arthritis (DAPSA) and Psoriasis Area and Severity Index (PASI) were used to evaluate the patients. The biochemical parameters of the patients were calculated. The serum levels of VEGF, HIF, and HO-1 were determined using an enzyme-linked immunosorbent assay.

Results

When the molecule levels and clinical features of the groups were evaluated, it was found that the VEGF and HIF-1 levels were higher in the patient group compared to the control group (p<0.05). No difference was observed in the comparison of the HO-1 levels of the patient group and the control group (p<0.05). A positive correlation was found between VEGF, HIF-1, and HO-1 (p<0.05). A positive relationship was found between VEGF and HIF-1 and erythrocyte sedimentation rate, C-reactive protein, DAPSA score, and PASI score (p<0.05). It was also determined that there was a positive relationship between the HIF molecule and DAS28 (p<0.05).

Conclusion

According to the results obtained in the present study, VEGF and HIF play a role in the etiology of PsA, and the observation of intermolecular correlation suggests that these molecules move together in pathogenesis.

Mesenchymal Stromal Cells-Derived Extracellular Vesicles as Potential Treatments for Osteoarthritis

Osteoarthritis (OA) is a degenerative disease of the joints characterized by cartilage damage and severe pain. Despite various pharmacological and surgical interventions, current therapies fail to halt OA progression, leading to high morbidity and an economic burden. Thus, there is an urgent need for alternative therapeutic approaches that can effectively address the underlying pathophysiology of OA. Extracellular Vesicles (EVs) derived from mesenchymal stromal cells (MSCs) represent a new paradigm in OA treatment. MSC-EVs are small membranous particles released by MSCs during culture, both in vitro and in vivo. They possess regenerative properties and can attenuate inflammation, thereby promoting cartilage healing. Importantly, MSC-EVs have several advantages over MSCs as cell-based therapies, including lower risks of immune reactions and ethical issues. Researchers have recently explored different strategies, such as modifying EVs to enhance their delivery, targeting efficiency, and security, with promising results. This article reviews how MSC-EVs can help treat OA and how they might work. It also briefly discusses the benefits and challenges of using MSC-EVs and talks about the possibility of allogeneic and autologous MSC-EVs for medical use.

Multi-omic characterization of brain changes in the vascular endothelial growth factor family during aging and Alzheimer's disease

The vascular endothelial growth factor (VEGF) signaling family has been implicated in neuroprotection and clinical progression in Alzheimer's disease (AD). Previous work in postmortem human dorsolateral prefrontal cortex demonstrated that higher transcript levels of VEGFB, PGF, FLT1, and FLT4 are associated with AD dementia, worse cognitive outcomes, and higher AD neuropathology. To expand prior work, we leveraged bulk RNA sequencing data, single nucleus RNA (snRNA) sequencing, and both tandem mass tag and selected reaction monitoring mass spectrometry proteomic measures from the post-mortem brain. Outcomes included AD diagnosis, cognition, and AD neuropathology. We replicated previously reported VEGFB and FLT1 results, whereby higher expression was associated with worse outcomes, and snRNA results suggest microglia, oligodendrocytes, and endothelia may play a central role in these associations. Additionally, FLT4 and NRP2 expression were associated with better cognitive outcomes. This study provides a comprehensive molecular picture of the VEGF signaling family in cognitive aging and AD and critical insight towards the biomarker and therapeutic potential of VEGF family members in AD.

Sex-dependent PD-L1/sPD-L1 trafficking in human endothelial cells in response to inflammatory cytokines and VEGF

Programmed cell death 1 ligand 1 (PD-L1) expressed in non-immune cells is involved in immune-mediated tissue damage in the context of inflammatory conditions and tumor immune escape. Emerging evidence suggests soluble (s)PD-L1 as a marker of inflammation. Based on well-established sex-specific differences in immunity, we tested the novel hypotheses that (i) endothelial cell PD-L1 is modulated by inflammatory cytokines and vascular endothelial growth factor (VEGF) in a sex-specific fashion, and (ii) the endothelium is a source of sPD-L1. After exposure of human umbilical vein endothelial cells (HUVECs) to lipopolysaccharide, interleukin (IL)1β or VEGF for 24 h, total PD-L1 levels were upregulated solely in cells from female donors, while being unchanged in those from male donors. Accordingly, exposure to synovial fluids from patients with inflammatory arthritis upregulated PD-L1 levels in HUVECs from female donors only. Membrane PD-L1 expression as measured by flow cytometry was unchanged in response to inflammatory stimuli. However, exposure to 2 ng/mL IL-1β or 50 ng/mL VEGF time-dependently increased sPD-L1 release by HUVECs from female donors. Treatment with the metalloproteinase (MMP) inhibitor GM6001 (10 μM) prevented IL-1β-induced sPD-L1 release and enhanced membrane PD-L1 levels. The anti-VEGF agents bevacizumab and sunitinib reduced both VEGF-induced PD-L1 accumulation and sPD-L1 secretion. Thus, inflammatory agents and VEGF rapidly increased endothelial PD-L1 levels in a sex-specific fashion. Furthermore, the vascular endothelium may be a sPD-L1 source, whose production is MMP-dependent and modulated by anti-VEGF agents. These findings may have implications for sex-specific immunity, vascular inflammation and response to anti-angiogenic therapy.

Matrix Metalloproteinase-9 Level in Synovial Fluid-Association with Joint Destruction in Early Rheumatoid Arthritis

Background and objective: Matrix metalloproteinases (MMPs) are the key enzymes in the pathogenesis of cartilage and joint damage and potentially a new biomarker of the early erosive form of rheumatoid arthritis (RA). Firstly, the study aimed to compare the level of MMP-9 in plasma (PL) and synovial fluid (SF) of patients with RA and osteoarthritis (OA). Secondly, the goal was to examine the association of MMP-9 level in PL and SF with early erosive changes in RA, and finally, to determine the association of MMP-9 level with serological parameters of the disease (rheumatoid factor-RF and anti-citrulline protein antibodies-ACPA). Materials and Methods: A total of 156 subjects were involved in this study (84 patients with RA and 72 patients with OA, who were involved as a control group). MMP-9 level was measured in PL and SF of all subjects by the sandwich enzyme-linked immunosorbent assay (ELISA) method. Standard radiographs of the hands and feet were used to detect joint damage and classification into erosive or non-erosive RA. The Larsen score (LS) was used for the quantitative assessment of joint damage, and its annual change (∆ LS) was used to assess the radiographic progression of the disease. Results: MMP-9 level in PL and SF was significantly higher in RA compared to controls (PL: 19.26 ± 7.54 vs. 14.57 ± 3.11 ng/mL, p< 0.01; SF: 16.17 ± 12.25 vs. 0.75 ± 0.53 ng/mL, p < 0.001) as well as in SF of patients with erosive compared to non-erosive RA (18.43 ± 12.87 vs. 9.36 ± 7.72; p < 0.05). Faster radiographic progression was recorded in erosive compared to non-erosive early RA (11.14 ± 4.75 vs. 6.13 ± 2.72; p < 0.01). MMP-9 level in SF, but not in PL, significantly correlates with the radiographic progression in both erosive and non-erosive RA (ρ = 0.38 and ρ = 0.27). We did not find a significant association between RF and MMP-9 level in early RA, but the ACPA level significantly correlates with MMP-9 level in SF (r = 0.48). Conclusion: The level of MMP-9 in plasma and synovial fluid of patients with RA is significantly higher compared to patients with osteoarthritis. The level of MMP-9 in synovial fluid is significantly higher in erosive than non-erosive early RA. It is significantly associated with the radiographic progression of the disease and the level of anti-citrulline protein antibodies.