Lena Claesson-Welsh's research projects in vascular biology

Src family kinases in vascular biology

Yindi DingPorträtt Yingdi Ding

The Src family kinases (SFK) are a group of non-receptor tyrosine kinases, which play important roles in cellular responses and oncogenesis. We are interested in the roles of different SFKs in vascular physiology, as well as how lipid metabolism is modulated by vascular SFKs.

Several mouse genetic models have been generated for the study. We use state-of-the-art imaging techniques to study cellular behaviours both in vivo and in vitro, accompanied by transcriptomic analyses (RNA sequencing to understand SFK gene regulation), to discover novel molecular mechanisms.

Microscope image of skin lipid layer
Image of developing mouse skin illustrating the adipose tissue status (vessel, red; adipose tissue, green; smooth muscle, white and nuclei, blue).

Prognostic implications of vascular leakage in human cancers

Emmanuel NwadoziPortrait Emmanuel Nwadozi

Vascular leakage is a hallmark of most solid tumours. Chronic leakage of macromolecules fosters an abnormal tumor microenvironment with increased interstitial pressure, impaired circulation and inflammation. Previously we showed that transgenic inhibition of vascular leakage suppressed metastasis and enhanced the efficacy of administered therapeutics in mouse tumour models.

The focus of the current work is to assess the prognostic implications of vascular leakage in human cancers (initially non-small cell lung cancer), with respect to survival, metastasis, the tumour immune contexture and response to immunotherapy. For this purpose, several cohorts of tumour microarrays are examined for vascular morphology and immune cell infiltration using high-content imaging technologies (i.e. imaging mass cytometry).

Microscope image of lung cancer tissue
A) Non small cell lung cancer tissue microarrays used for immunohistochemical stainings and analyses. B) Sample image showing select immune markers from a 30-plex imaging mass cytometry panel and C-D) semi-supervised cell phenotyping strategy used for analyses.

The impact of Src family kinases in tumour leakage and vascular normalization

Portrait Emmanuel Nwadozi    Emmanuel Nwadozi, Laura Maeso

In this project, we assess the molecular regulation of vascular leakage within tumours by Src family kinase (SFK) members Src, Yes and Fyn. SFKs are known to regulate vascular leakage downstream of VEGFA. However, in the healthy dermis, loss of Src expression in endothelial cells leads to suppressed vascular leakage, while loss of endothelial Yes leads to exaggerated leakage (Jin et al., Portrait Laura MaesoNat CVR 2022). In contrast, our ongoing study indicates that targeting SFK’s in the vascular endothelium suppresses tumour leakage and normalizes the vasculature within tumours.

The overarching aim of this study is to determine whether specific targeting of leakage-specific pathways downstream of VEGFA could serve as a therapeutic means to normalize the tumor vasculature, circumventing adverse effects of broad inhibition of VEGFA, that is currently used as the gold standard of vascular targeted anti-tumour therapy.

Microscope images of mouse breast cancer tumour sections
Mouse breast cancer tumour sections showing immunostainings used to study different tumuor parameters.
Left: Vascular permeability is analyzed by the quantification of the extravasated fibrinogen (red) (blue arrows show fibrinogen depositions), relative to the vasculature (CD31, green) in the tumour (white). Middle: For vessel perfusion, Lectin (red) positive vessels (CD31-green) are quantified. Right: EF5 (green) is a chemical that selectively binds to hypoxic cells (red: tumoural cells).

Understanding VEGFA mediated vascular permeability: its regulation, signalling and patterns

Portrait Sagnik PalSagnik Pal

Pathological conditions such as cancer, retinopathies and acute/chronic inflammation cause endothelial barrier disruption, leading to leaky vessels and disease progression. Therapies targeting VEGFA/VEGFR2 allow junction normalization but at the cost of blood vessel regression. We are interested in elucidating key pathways downstream of VEGFR2, co-receptor NRP1 and tyrosine phosphatase VE-PTP.

Taking advantage of a sophisticated intravital imaging technique developed in the lab (Honkura et al. 2018), we are able to visualize and analyse vascular leakage in real time with higher spatio-temporal resolution. Furthermore, we use techniques to investigate organotypic patterns of vascular permeability.

Microscope images of vascular leakage
Vascular leakage in response to VEGFA injection. Mice are intravenously injected with fluorescent dextran to visualise the vessels followed by surgical anaesthesia. Images show real time dextran leakage (purple) from vessels when injected with VEGFA mixed with a fluorescent tracer (green) (left: just before injection; right: 200 seconds after injection)  using a micro-capillary needle in the ear skin of mouse.

Suppressing VEGF-induced vascular leakage in eye disease

Yangyang SuPortrait of Yangyang Su

The prevalence of severe vision impairment and blindness is steadily increasing in conjunction with increased longevity and increased prevalence of diseases associated with a sedentary life style and western diet. Vision impairment and blindness are manifested in diseases such as age-related macular degeneration and diabetic retinopathy, conditions which are accompanied by retinal edema due to vascular instability and dysfunctions.

Blood vessels normally retain large molecules and cells in the blood. However, in retinopathies, vessels leak blood constituents, creating edema and inflammation. Current treatment involves injection of antibodies to VEGF into the eye, which has potential side effects and risks.
In this project, we have used a high throughput screen to identify a small molecular weight inhibitor, which blocks formation of VEGFA-induced edema.

Microscope images of vessel leakage
Immunofluorescent staining with antibodies against VE-cadherin (VEC) and pVEC Y685 in the back skin of WT after intradermal injection of PBS or VEGFA. Image to the lower right shows increased phosphorylation of the junctional protein VE-cadherin in response to VEGFA, indicating junction instability and vascular leakage.

Last modified: 2023-11-29