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Biology subjects

Shaked, I.

Publications and source records attributed to Shaked, I..

3 recordsLinked to original sources

A lone spike in blood glucose can enhance the thrombo-inflammatory response in cortical venules

How transient hyperglycemia contributes to cerebro-vascular disease has been a challenge to study under controlled conditions. We present an approach to model luminal vessel thrombo-inflammation using amplified, ultrashort laser-pulses to physically disrupt brain-venule endothelium. Vessel disruption in conjunction with transient hyperglycemia from a single injection of metabolically active D-glucose results in real-time responses to venule damage that include rapid serum extravasation, platelet aggregation, and neutrophil recruitment, in normal mice. In contrast, vessel thrombo-inflammation following laser-induced vessel disruption is significantly reduced in mice injected with metabolically inert L-glucose. Thrombo-inflammation is pharmacologically ameliorated by a platelet inhibitor, by a scavenger of reactive oxygen species, or by a nitric oxide donor. For comparison, in diabetic mice injured vessel thrombo-inflammatory responses are also reduced by restoration of normo-glycemia. Our approach provides a controlled method to probe synergies of transient metabolic and physical vascular perturbations and reveals new aspects of brain pathophysiology.

neuroscience↗

Abortive Intussusceptive Angiogenesis Causes Multi-Cavernous Vascular Malformations

Mosaic inactivation of CCM2 in humans causes cerebral cavernous malformations (CCMs) containing adjacent dilated blood-filled multi-cavernous lesions. We used CRISPR-Cas9 mutagenesis to induce mosaic inactivation of zebrafish ccm2 resulting in a novel lethal multi-cavernous lesion in the embryonic caudal venous plexus (CVP) caused by obstruction of blood flow by intraluminal pillars. These pillars mimic those that mediate intussusceptive angiogenesis; however, in contrast to the normal process, the pillars failed to fuse to split the pre-existing vessel in two. Abortive intussusceptive angiogenesis stemmed from mosaic inactivation of ccm2 leading to patchy klf2a over-expression and resultant aberrant flow signaling. Surviving adult fish manifested histologically-typical hemorrhagic CCM. Formation of mammalian CCM requires the flow-regulated transcription factor KLF2; fish CCM and the embryonic CVP lesion failed to form in klf2a null fish indicating a common pathogenesis with the mammalian lesion. These studies describe a zebrafish CCM model and establish a mechanism that can explain the formation of characteristic multi-cavernous lesions.

developmental biology↗

Endothelial struts, a mechanism to generate large lumenized blood vessels de novo

Lumenization of de novo formed blood vessels occurs either through cell hollowing (intracellular lumen)1-3 or cord hollowing (extracellular lumen)4-6 and restricts thereby the initial lumen diameter to one or two endothelial cells (ECs) respectively. However, vasculogenesis can result in large diameter blood vessels, raising the question how these vessels are formed. Here, we describe an alternative model of vasculogenesis that results in the formation of large diameter vessels. In this model, ECs coalesce into a branched network of EC struts within the future lumen of the vessel. These struts maintain the patency of the vessel and serve as a scaffold for the ECs forming the vessel wall, which initially consists out of a few patches of ECs. Together, we show that endothelial struts facilitate the formation of large blood vessels without being bound by the prerequisite of a cord-like structure, nor are they restricted in size.

developmental biology↗