Identification of factor H-like protein 1 as the predominant complement regulator in Bruch's membrane: implications for age-related macular degeneration.

The tight regulation of innate immunity on extracellular matrix (ECM) is a vital part of immune homeostasis throughout the human body, and disruption to this regulation in the eye is thought to contribute directly to the progression of age-related macular degeneration (AMD). The plasma complement regulator factor H (FH) is thought to be the main regulator that protects ECM against damaging complement activation. However, in the present study we demonstrate that a truncated form of FH, called FH-like protein 1 (FHL-1), is the main regulatory protein in the layer of ECM under human retina, called Bruch's membrane. Bruch's membrane is a major site of AMD disease pathogenesis and where drusen, the hallmark lesions of AMD, form. We show that FHL-1 can passively diffuse through Bruch's membrane, whereas the full sized, glycosylated, FH cannot. FHL-1 is largely bound to Bruch's membrane through interactions with heparan sulfate, and we show that the common Y402H polymorphism in the CFH gene, associated with an increased risk of AMD, reduces the binding of FHL-1 to this heparan sulfate. We also show that FHL-1 is retained in drusen whereas FH coats the periphery of the lesions, perhaps inhibiting their clearance. Our results identify a novel mechanism of complement regulation in the human eye, which highlights potential new avenues for therapeutic strategies.

Disinfection of Neonatal Resuscitation Equipment in Low-Resource Settings: The Importance, the Reality, and Considerations for the Future.

Preventable neonatal deaths due to prematurity, perinatal events, and infections are the leading causes of under-five mortality. The vast majority of these deaths are in resource-limited areas. Deaths due to infection have been associated with lack of access to clean water, overcrowded nurseries, and improper disinfection (reprocessing) of equipment, including vital resuscitation equipment. Reprocessing has recently come to heightened attention, with the COVID-19 pandemic bringing this issue to the forefront across all economic levels; however, it is particularly challenging in low-resource settings. In 2015, Eslami et al. published a letter to the editor in Resuscitation, highlighting concerns about the disinfection of equipment being used to resuscitate newborns in Kenya. To address the issue of improper disinfection, the global health nongovernment organization PATH gathered a group of experts and, due to lack of best-practice evidence, published guidelines with recommendations for reprocessing of neonatal resuscitation equipment in low-resource areas. The guidelines follow the gold-standard principle of high-level disinfection; however, there is ongoing concern that the complexity of the guideline would make feasibility and sustainability difficult in the settings for which it was designed. Observations from hospitals in Kenya and Malawi reinforce this concern. The purpose of this review is to discuss why proper disinfection of equipment is important, why this is challenging in low-resource settings, and suggestions for solutions to move forward.

AZD7762, a novel checkpoint kinase inhibitor, drives checkpoint abrogation and potentiates DNA-targeted therapies.

Insights from cell cycle research have led to the hypothesis that tumors may be selectively sensitized to DNA-damaging agents resulting in improved antitumor activity and a wider therapeutic margin. The theory relies on the observation that the majority of tumors are deficient in the G1-DNA damage checkpoint pathway resulting in reliance on S and G2 checkpoints for DNA repair and cell survival. The S and G2 checkpoints are regulated by checkpoint kinase 1, a serine/threonine kinase that is activated in response to DNA damage; thus, inhibition of checkpoint kinase 1 signaling impairs DNA repair and increases tumor cell death. Normal tissues, however, have a functioning G1 checkpoint signaling pathway allowing for DNA repair and cell survival. Here, we describe the preclinical profile of AZD7762, a potent ATP-competitive checkpoint kinase inhibitor in clinical trials. AZD7762 has been profiled extensively in vitro and in vivo in combination with DNA-damaging agents and has been shown to potentiate response in several different settings where inhibition of checkpoint kinase results in the abrogation of DNA damage-induced cell cycle arrest. Dose-dependent potentiation of antitumor activity, when AZD7762 is administered in combination with DNA-damaging agents, has been observed in multiple xenograft models with several DNA-damaging agents, further supporting the potential of checkpoint kinase inhibitors to enhance the efficacy of both conventional chemotherapy and radiotherapy and increase patient response rates in a variety of settings.

Sustained Mps1 activity is required in mitosis to recruit O-Mad2 to the Mad1-C-Mad2 core complex.

Mps1 is an essential component of the spindle assembly checkpoint. In this study, we describe a novel Mps1 inhibitor, AZ3146, and use it to probe the role of Mps1's catalytic activity during mitosis. When Mps1 is inhibited before mitotic entry, subsequent recruitment of Mad1 and Mad2 to kinetochores is abolished. However, if Mps1 is inhibited after mitotic entry, the Mad1-C-Mad2 core complex remains kinetochore bound, but O-Mad2 is not recruited to the core. Although inhibiting Mps1 also interferes with chromosome alignment, we see no obvious effect on aurora B activity. In contrast, kinetochore recruitment of centromere protein E (CENP-E), a kinesin-related motor protein, is severely impaired. Strikingly, inhibition of Mps1 significantly increases its own abundance at kinetochores. Furthermore, we show that Mps1 can dimerize and transphosphorylate in cells. We propose a model whereby Mps1 transphosphorylation results in its release from kinetochores, thus facilitating recruitment of O-Mad2 and CENP-E and thereby simultaneously promoting checkpoint signaling and chromosome congression.