In ovo administration of human recombinant leptin shows dose dependent angiogenic effect on chicken chorioallantoic membrane

Abstract

BackgroundLeptin, the cytokine produced by white adipose tissue is known to regulate food energy homeostasis through its hypothalamic receptor. In vitro studies have demonstrated that leptin plays a major role in angiogenesis through binding to the receptor Ob-R present on ECs by stimulating and initiating new capillary like structures from ECs. Various in vivo studies indicate that leptin has diverse effect on angiogenesis. A few reports have showed that leptin exerts pro angiogenic effects while some suggested that it has antiangiogenic potential. It is theoretically highly important to understand the effect of leptin on angiogenesis to use as a therapeutic molecule in various angiogenesis related pathological conditions. Chicken chorio allantoic membrane (CAM) on 9th day of incubation was incubated with 1, 3 and 5 μg concentration of HRL for 72 h using gelatin sponge. Images where taken after every 24 h of incubation and analysed with Angioguant software. The treated area was observed under microscope and histological evaluation was performed for the same. Tissue thickness was calculated morphometrically from haematoxylin and eosin stained cross sections. Reverse transcriptase PCR and immunohistochemistry were also performed to study the gene and protein level expression of angiogenic molecules.ResultsHRL has the ability to induce new vessel formation at the treated area and growth of the newly formed vessels and cellular morphological changes occur in a dose dependent manner. Increase in the tissue thickness at the treated area is suggestive of initiation of new capillary like structures. Elevated mRNA and protein level expression of VEGF165 and MMP2 along with the activation of ECs as demonstrated by the presence of CD34 expression supports the neovascularization potential of HRL.ConclusionAngiogenic potential of HRL depends on the concentration and time of incubation and is involved in the activation of ECs along with the major interaction of VEGF 165 and MMP2. It is also observed that 3 μg of HRL exhibits maximum angiogenic potential at 72 h of incubation. Thus our data suggest that dose dependent angiogenic potential HRL could provide a novel role in angiogenic dependent therapeutics such as ischemia and wound healing conditions.

AMP-Activated Protein Kinase Mediates the Effect of Leptin on Avian Autophagy in a Tissue-Specific Manner

“…Although the sequence of chicken leptin gene was a matter of intense debate for almost 20 years (Taouis et al, 1998 ; Ashwell et al, 1999 ; Seroussi et al, 2016 ), the chicken leptin receptor sequence however was found to have at least 60% homology with the mammalian orthologs with highly conserved motifs in the transmembrane domain (Horev et al, 2000 ; Ohkubo et al, 2000 ). Moreover, previous in vitro and in vivo studies have shown that chicken leptin receptor is responsive to recombinant mammalian (mouse, human, and ovine) leptins (Denbow et al, 2000 ; Dridi et al, 2000 ; Lohmus et al, 2003 ; Lõhmus et al, 2004 ; Manjunathan and Ragunathan, 2015 ). As the recombinant protein for the newly discovered chicken leptin (Seroussi et al, 2016 ) was not available at the time we undertook this study, we determined whether recombinant ovine leptin can modulate the autophagy pathway in vivo following ICV administration to broiler chickens.…”

Renin–angiotensin system gene polymorphisms and endometrial cancer

“…In vitro , LEP secreted from obese adipose tissue stromal cells enhanced growth of ER + breast cancer cells (36). LEP also stimulates angiogenesis ( 37 , 38 ). Therefore, in obese women, not only are there higher oestrogen levels but there are also higher levels of LEP which is tumourigenic both through its direct actions and possibly by its ability to stimulate the RAS, although it is only one of a number of pathways through which Ang II levels are increased in obesity.…”

Methanolic extract of Euchelus asper exhibits in-ovo anti-angiogenic and in vitro anti-proliferative activities

“…One such study by Huang et al [ 26 ] demonstrated that Phyllanthus urinaria efficiently inhibited embryonic angiogenesis by reducing the MMP-2 activity in the CAM model. Another interesting research conducted by Manjunathan et al [ 27 ] explained the positive angiogenic activity of human recombinant leptin (HRL) in chick CAM model. Their findings verify that the angiogenic response of HRL was due to increase in MMP-2 levels in CAM which caused breakdown of ECM in favour of migration and proliferation of ECs thus supporting the occurrence of sprouting angiogenesis.…”