Lymph node removal enhances corneal graft survival in mice at high risk of rejection

Peer reviewedPublisher PD

Actin Cytoskeleton Regulation by the Yeast NADPH Oxidase Yno1p Impacts Processes Controlled by MAPK Pathways

Reactive oxygen species (ROS) that exceed the antioxidative capacity of the cell can be harmful and are termed oxidative stress. Increasing evidence suggests that ROS are not exclusively detrimental, but can fulfill important signaling functions. Recently, we have been able to demonstrate that a NADPH oxidase-like enzyme (termed Yno1p) exists in the single-celled organism Saccharomyces cerevisiae. This enzyme resides in the peripheral and perinuclear endoplasmic reticulum and functions in close proximity to the plasma membrane. Its product, hydrogen peroxide, which is also produced by the action of the superoxide dismutase, Sod1p, influences signaling of key regulatory proteins Ras2p and Yck1p/2p. In the present work, we demonstrate that Yno1p-derived H2O2 regulates outputs controlled by three MAP kinase pathways that can share components: the filamentous growth (filamentous growth MAPK (fMAPK)), pheromone response, and osmotic stress response (hyperosmolarity glycerol response, HOG) pathways. A key structural component and regulator in this process is the actin cytoskeleton. The nucleation and stabilization of actin are regulated by Yno1p. Cells lacking YNO1 showed reduced invasive growth, which could be reversed by stimulation of actin nucleation. Additionally, under osmotic stress, the vacuoles of a ∆yno1 strain show an enhanced fragmentation. During pheromone response induced by the addition of alpha-factor, Yno1p is responsible for a burst of ROS. Collectively, these results broaden the roles of ROS to encompass microbial differentiation responses and stress responses controlled by MAPK pathway

Ophthalmology

PURPOSE: To evaluate the 2-year efficacy, durability, and safety of dual angiopoietin-2/vascular endothelial growth factor (VEGF)-A pathway inhibition with intravitreal faricimab according to a personalized treat-and-extend-based regimen (T&E) with up to every-16-week (Q16W) dosing in the YOSEMITE/RHINE (NCT03622580/NCT03622593) phase 3 trials of diabetic macular edema (DME). DESIGN: Randomized, double-masked, noninferiority phase 3 trials. PARTICIPANTS: Adults with visual acuity loss due to center-involving DME. METHODS: Patients were randomized 1:1:1 to faricimab 6.0 mg Q8W, faricimab 6.0 mg T&E (previously referred to as personalized treatment interval), or aflibercept 2.0 mg Q8W. The T&E up to Q16W dosing regimen was based on central subfield thickness (CST) and best-corrected visual acuity (BCVA) change. MAIN OUTCOME MEASURES: Included changes from baseline in BCVA and CST, number of injections, durability, absence of fluid, and safety through week 100. RESULTS: In YOSEMITE/RHINE (N=940/951), noninferior year 1 visual acuity gains were maintained through year 2; mean BCVA change from baseline at 2 years (weeks 92/96/100 average) with faricimab Q8W (YOSEMITE/RHINE, +10.7/+10.9 letters) or T&E (+10.7/+10.1 letters) were comparable with aflibercept Q8W (+11.4/+9.4 letters). The median number of study drug injections was lower with faricimab T&E (YOSEMITE/RHINE, 10/11 injections) versus faricimab Q8W (15 injections) and aflibercept Q8W (14 injections) across both trials during the entire study. In the faricimab T&E arms, durability was further improved during year 2, with >60% of patients on Q16W dosing and ∼80% on ≥Q12W dosing at week 96. Almost 80% of patients who achieved Q16W dosing at week 52 maintained Q16W dosing without an interval reduction through week 96. Mean CST reductions were greater, and more patients achieved absence of DME (CST <325μm) and absence of intraretinal fluid with faricimab Q8W or T&E versus aflibercept Q8W through year 2. Overall, faricimab was well tolerated, with a safety profile comparable to aflibercept. CONCLUSIONS: Clinically meaningful visual acuity gains from baseline, anatomic improvements, and extended durability with intravitreal faricimab up to Q16W were maintained through year 2. Faricimab given as a personalized T&E-based dosing regimen supports the role of dual angiopoietin-2/VEGF-A inhibition to promote vascular stability and provide durable efficacy for patients with DME

Mechanism of cellular rejection in transplantation

The explosion of new discoveries in the field of immunology has provided new insights into mechanisms that promote an immune response directed against a transplanted organ. Central to the allograft response are T lymphocytes. This review summarizes the current literature on allorecognition, costimulation, memory T cells, T cell migration, and their role in both acute and chronic graft destruction. An in depth understanding of the cellular mechanisms that result in both acute and chronic allograft rejection will provide new strategies and targeted therapeutics capable of inducing long-lasting, allograft-specific tolerance