The endogenous e pression of podoplanin on 293T cells and also the distinct interaction of podoplanin with CLEC two raised the inquiries different if podoplanin was incorpo rated into virions made in 293T cells, and if incorpo ration of podoplanin was necessary for CLEC two binding of those virions. Western blot analysis and knock down of podoplanin e pression by shRNA presented affirmative answers to both questions Podoplanin depletion decreased CLEC two, but not DC Indicator, dependent HIV 1 transmis sion by B THP cells, and diminished transmission by platelets by about 50%. The latter finding is in agreement with our prior observation that CLEC two certain antiserum diminished HIV 1 transmission by plate lets by about half. Podoplanin hence joins the list of host aspects which might be incorporated to the HIV one envelope and affect HIV one infection by interacting with their cognate ligands.
A prominent e ample for this kind of a issue is ICAM one Olaparib which was located to be incorpo rated to the viral membrane, and to facilitate HIV one infection by binding to its ligand LFA one on T cells. The probable relevance of podoplanin incorporation for HIV spread in contaminated people is critically deter mined through the overlap in the podoplanin e pression pat tern with the cellular tropism of HIV. Examination of T cell lines and PBMCs for podoplanin e pression yielded neg ative effects, at least when viable cells have been ana lyzed, indicating that HIV particles created in patients might not harbour podoplanin. The e ception is likely to be viruses launched from kidney podocytes which are documented to e press podoplanin and to be vulnerable to HIV infection.
Nonetheless, the biolog ical relevance of this approach is questionable. On this con te t, in addition, it has to be mentioned that podoplanin e pression is up regulated in lots of tumours such as Kaposi sar coma. Podoplanin CLEC two dependent platelet stimulation by tumour cells promotes hematogenous tumour metastasis, INK-128 quite possibly by inducing development factor secretion by platelets and by promoting formation of the platelet cap, which protects the tumour from mechanical forces. So, podoplanin may well perform a part while in the advancement of the AIDS related Kaposi sarcoma, but is unlikely to modulate HIV spread in individuals. Nev ertheless, HIV one generated in PBMCs was transmitted to target cells within a CLEC 2 dependent trend, sug gesting that key T cells may well e press a to date unrec ognized CLEC two ligand, that is incorporated into the viral envelope and which facilitates HIV transmission by CLEC 2.
Our ongoing studies are devoted towards the identification of this component. Podoplanin was not detected on viable CEM��174 cells and PBMCs, as established by our gat ing system and by co staining with all the apoptosis and necrosis markers anne in V and seven AAD, respectively.