VEGF on Michael’s Domain

OMG: T. rex did not have VEGF-B!

Wed, 05 Apr 2023 00:00:00 +0000

Our work on the evolutionary origin of the PDGF and VEGF growth factors has just been published in Angiogenesis: https://doi.org/10.1007/s10456-023-09874-9 . We analyzed both PDGFs and VEGFs, but our focus was naturally on the VEGF side of things. It’s just a coincidence that the PDGFs happened to be a subgroup of the VEGFs and not vice versa, but that’s of course just our biased point of view :-)Since we do lymphatic research, we can proudly announce that the phylogenetic oldest VEGF likely resembled VEGF-C and featured the enigmatic silk homology domain. It makes intuitive sense (and had been proposed before by Jörg Wilting), because the most simple vascular systems that we know of are the so-called hemolymph systems (e.g., in insects), which share many features with the lymphatic system.With this publication, we did not do something exceptional that only a few can do. We did something everybody could do but nobody had done so far: looking systematically at which animals have which PDGFs and VEGFs. Actually, we did something new: we developed a crowdsourcing method for classifying PDGFs and VEGFs. Instead of asking people, we asked databases. There are many PDGF-like and VEGF-like sequences in databases, which are only recognizable as such by the homology of their amino acid sequence. In order to know whether we are dealing, e.g., with a VEGF-C or a VEGF-D, we are running many (PSI)BLAST searches, and then we tally up the majority opinion (as determined by the top hits).Many surprises waited for us after the bioinformatics script had finished its job after two weeks of finding and comparing PDGF- and VEGF-like sequences:

The evolution of PDGF/VEGF growth factors

Thu, 22 Sep 2022 00:00:00 +0000

We have uploaded a preprint of our most recent manuscript about the evolution of PDGF/VEGF growth factors to bioRxiv. We comprehensively analyzed the PDGF/VEGF part of the proteome in all animal species for which data is available. We have had some of this data already for a while, but now we enhance it with a detailed look at fishes. The vascular biology of fishes has become even more facinating after the publication of Das et al. earlier this year ( read more about this exceptional piece of work ).The remarkable heterogeneity of vascular systems in fishes seems to be supported by a similar extensive heterogeneity at the molecular level. Often, but not always can this genetic heterogeneity be traced back to whole genome duplications. Fishes tolerate full genome duplications better than mammals. At least there have been quite a few such duplications in various branches of the fish phylogenetic tree resulting in polyploid or even tetraploid species. That has resulted in some fish species featuring 4 times as many PDGF/VEGF genes compared to humans, and much more opportunities to diversify the functions of these molecules.The very first PDGF/VEGF-like molecule appeared likely more than 800 Million years ago during the Precambrian period when marine organisms started to show signs of tissue organization. If we set out to reconstruct this molecule, it would look remarkably similar to a modern VEGF-C. Specifically the C-terminal “silk homology domain” seems to have been invented early on in evolution. In fact, a large number of extant morphologically simple organisms feature such VEGF-C-like molecules still today (e.g. the nematode C. elegans). Beyond these insights into the evolution of PDGFs and VEGFs, there are some useful take-home messages for vascular biologists: For example, we did not find any functional VEGF-B genes in birds. Similarly, there seem to be no PlGFs in amphibians. Then, on the other hand, the VEGF-Fs - identified from snake venoms - appear to exist more broadly also in non-venomous lizards. This poses some limitations on some animal models (Xenopus, CAM assay), but it would be nice to know what VEGF-F is doing in geckos…Have a look at the manuscript and please comment or criticize, if you have any thoughts! The idea is to make this manuscript still a bit better before submitting it to a journal for the traditional peer-review.

A Nobel Prize for angiogenesis research?

Sun, 27 Oct 2013 00:00:00 +0000

In 2008, during a dinner in Stockholm (when I participated in the Novo Nordisk Foundation 8th Annual Conference on Vascular Biology in Diabetes Complications) I proposed to Christer Betsholtz to award the Nobel Prize to the world-wide community of postdocs, which are the unsung heroes of today’s research. But the Statutes of the Nobel Foundation forbid to award the price to more than three people. However, statutes can be changed and the Nobel Foundation did exactly that 40 years ago when they stopped awarding the price to dead people. And in this changing world, less and less discoveries and inventions are made by individuals. But here’s my newest proposal, which adheres to the rule of maximally three: Kari Alitalo is probably the only Nobel Prize worthy researcher in the country where I work (Finland). Seriously: after Judah Folkman has passed away, there are not many options to award the prize to somebody from the angiogenesis field. Judah Folkman was the father of the hypothesis, that all tumors should be treatable by anti-angiogenesis ( Folkman J. Tumor Angiogenesis: Therapeutic Implications. New England Journal of Medicine. 1971;285(21):1182–6 ). The Nobel Prize committee missed that chance. And because the field has already significantly contributed to the treatment of cancer (and arguably will still contribute much), it is not so far off to think of a shared prize for the discoverers of the VEGFs. VEGF was discovered more or less independently by several research groups around 25 years ago, among them Napoleone Ferrara ’s and Harold Dvorak ’s. Most notably, Ferrara’s group at Genentech continued the research most successfully until today resulting in the first antiangiogenic cancer drug in 2004. While the discovery of VEGF and the resulting angiogenesis research was not dependent on any single lab, the lymphangiogenesis field was essentially single-handedly re-invented and brought into the molecular era by Kari Alitalo in the years following 1995 - after it had become senile and was lingering without any significant progress since the 1960s. A shared prize to Ferrara, Dvorak and Alitalo? There is an anti-VEGF-A cancer drug on the market and the only thing lacking is a successful anti- or pro-VEGF-C drug. Both are in clinical trials as of this writing ( anti-VEGF-C , pro-VEGF-C ).