The Pacific Standard highlights “Efficient phagocytosis and laccase activity affect the outcome of HIV-associated cryptococcosis” by Wilber Sabiiti and colleagues. Read the accompanying Commentary “Cryptococcosis: a model for the understanding of infectious diseases” by John Perfect.
The Cleveland Plain Dealer reports on “Lipotoxic disruption of NHE1 interaction with PI(4,5)P2 expedites proximal tubule apoptosis” by Jeffrey Schelling and colleagues.
ScienceBlog discusses “Tumor endothelial marker 1–specific DNA vaccination targets tumor vasculature” by Andrea Facciabene and colleagues.
Wilber Sabiiti, Emma Robertson, Mathew A. Beale, Simon A. Johnston, Annemarie E. Brouwer, Angela Loyse, Joseph N. Jarvis, Andrew S. Gilbert, Matthew C. Fisher, Thomas S. Harrison, Robin C. May, Tihana Bicanic
The increase in immunosuppressed patient populations has correlated with a rise in clinical fungal infections, including cryptococcosis. Patient outcome following
John R. Perfect
Chronic kidney disease progression can be predicted based on the degree of tubular atrophy, which is the result of proximal tubule apoptosis. The Na+/H+ exchanger NHE1 regulates proximal tubule cell survival through interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], but pathophysiologic triggers for NHE1 inactivation are unknown. Because glomerular injury permits proximal tubule luminal exposure and reabsorption of fatty acid/albumin complexes, we hypothesized that accumulation of amphipathic, long-chain acyl-CoA (LC-CoA) metabolites stimulates lipoapoptosis by competing with the structurally similar PI(4,5)P2 for NHE1 binding. Kidneys from mouse models of progressive, albuminuric kidney disease exhibited increased fatty acids, LC-CoAs, and caspase-2–dependent proximal tubule lipoapoptosis. LC-CoAs and the cytosolic domain of NHE1 directly interacted, with an affinity comparable to that of the PI(4,5)P2-NHE1 interaction, and competing LC-CoAs disrupted binding of the NHE1 cytosolic tail to PI(4,5)P2. Inhibition of LC-CoA catabolism reduced NHE1 activity and enhanced apoptosis, whereas inhibition of proximal tubule LC-CoA generation preserved NHE1 activity and protected against apoptosis. Our data indicate that albuminuria/lipiduria enhances lipotoxin delivery to the proximal tubule and accumulation of LC-CoAs contributes to tubular atrophy by severing the NHE1-PI(4,5)P2 interaction, thereby lowering the apoptotic threshold. Furthermore, these data suggest that NHE1 functions as a metabolic sensor for lipotoxicity.
Shenaz Khan, Bassam G. Abu Jawdeh, Monu Goel, William P. Schilling, Mark D. Parker, Michelle A. Puchowicz, Satya P. Yadav, Raymond C. Harris, Ashraf El-Meanawy, Malcolm Hoshi, Krekwit Shinlapawittayatorn, Isabelle Deschênes, Eckhard Ficker, Jeffrey R. Schelling
Tumor endothelial marker 1 (TEM1; also known as endosialin or CD248) is a protein found on tumor vasculature and in tumor stroma. Here, we tested whether TEM1 has potential as a therapeutic target for cancer immunotherapy by immunizing immunocompetent mice with
John G. Facciponte, Stefano Ugel, Francesco De Sanctis, Chunsheng Li, Liping Wang, Gautham Nair, Sandy Sehgal, Arjun Raj, Efthymia Matthaiou, George Coukos, Andrea Facciabene