In vitro and ex vivo models of microbial keratitis: Present and future.

Microbial keratitis (MK) is an infection of the cornea, caused by bacteria, fungi, parasites, or viruses. MK leads to significant morbidity, being the fifth leading cause of blindness worldwide. There is an urgent requirement to better understand pathogenesis in order to develop novel diagnostic and therapeutic approaches to improve patient outcomes.

Photosensitizer-Amplified Antimicrobial Materials for Broad-Spectrum Ablation of Resistant Pathogens in Ocular Infections.

The emergence of multidrug resistant (MDR) pathogens and the scarcity of new potent antibiotics and antifungals are one of the biggest threats to human health. Antimicrobial photodynamic therapy (aPDT) combines light and photosensitizers to kill drug-resistant pathogens; however, there are limited materials that can effectively ablate different classes of infective pathogens. In the present work, a new class of benzodiazole-paired materials is designed as highly potent PDT agents with broad-spectrum antimicrobial activity upon illumination with nontoxic light.

Rapid Point-of-Care Identification of Aspergillus Species in Microbial Keratitis.

Importance: Microbial keratitis (MK) is a common cause of unilateral visual impairment, blindness, and eye loss in low-income and middle-income countries. There is an urgent need to develop and implement rapid and simple point-of-care diagnostics for MK to increase the likelihood of good outcomes.

Objective: To evaluate the diagnostic performance of the Aspergillus-specific lateral-flow device (AspLFD) to identify Aspergillus species causing MK in corneal scrape and corneal swab samples of patients presenting with microbial keratitis.

FluoroPi Device With SmartProbes: A Frugal Point-of-Care System for Fluorescent Detection of Bacteria From a Pre-Clinical Model of Microbial Keratitis.

Purpose: Rapid and accurate diagnosis of microbial keratitis (MK) could greatly improve patient outcomes. Here, we present the development of a rapid, accessible multicolour fluorescence imaging device (FluoroPi) and evaluate its performance in combination with fluorescent optical reporters (SmartProbes) to distinguish bacterial Gram status. Furthermore, we show feasibility by imaging samples obtained by corneal scrape and minimally invasive corneal impression membrane (CIM) from ex vivo porcine corneal MK models.

Molecular detection of Gram-positive bacteria in the human lung through an optical fiber-based endoscope.

Purpose: The relentless rise in antimicrobial resistance is a major societal challenge and requires, as part of its solution, a better understanding of bacterial colonization and infection. To facilitate this, we developed a highly efficient no-wash red optical molecular imaging agent that enables the rapid, selective, and specific visualization of Gram-positive bacteria through a bespoke optical fiber-based delivery/imaging endoscopic device.

Methods: We rationally designed a no-wash, red, Gram-positive-specific molecular imaging agent (Merocy-Van) based on vancomycin and an environmental merocyanine dye.

Polymyxin-based photosensitizer for the potent and selective killing of Gram-negative bacteria.

Here we report the synthesis of a novel methylene blue-polymyxin conjugate and demonstrate its light-mediated killing of Gram-negative bacteria on skin models of infection demonstrating a 10 decrease in bacterial colony-forming units.

Ym1 induces RELMα and rescues IL-4Rα deficiency in lung repair during nematode infection.

Ym1 and RELMα are established effector molecules closely synonymous with Th2-type inflammation and associated pathology. Here, we show that whilst largely dependent on IL-4Rα signaling during a type 2 response, Ym1 and RELMα also have IL-4Rα-independent expression patterns in the lung. Notably, we found that Ym1 has opposing effects on type 2 immunity during nematode infection depending on whether it is expressed at the time of innate or adaptive responses.

Macrophage origin limits functional plasticity in helminth-bacterial co-infection.

Rapid reprogramming of the macrophage activation phenotype is considered important in the defense against consecutive infection with diverse infectious agents. However, in the setting of persistent, chronic infection the functional importance of macrophage-intrinsic adaptation to changing environments vs. recruitment of new macrophages remains unclear.

IL-33 delivery induces serous cavity macrophage proliferation independent of interleukin-4 receptor alpha.

IL-33 plays an important role in the initiation of type-2 immune responses, as well as the enhancement of type 2 effector functions. Engagement of the IL-33 receptor on macrophages facilitates polarization to an alternative activation state by amplifying IL-4 and IL-13 signaling to IL-4Rα. IL-4 and IL-13 also induce macrophage proliferation but IL-33 involvement in this process has not been rigorously evaluated.

Fat-associated lymphoid clusters control local IgM secretion during pleural infection and lung inflammation.

Fat-associated lymphoid clusters (FALC) are inducible structures that support rapid innate-like B-cell immune responses in the serous cavities. Little is known about the physiological cues that activate FALCs in the pleural cavity and more generally the mechanisms controlling B-cell activation in FALCs. Here we show, using separate models of pleural nematode infection with Litomosoides sigmodontis and Altenaria alternata induced acute lung inflammation, that inflammation of the pleural cavity rapidly activates mediastinal and pericardial FALCs.

IL-4 directly signals tissue-resident macrophages to proliferate beyond homeostatic levels controlled by CSF-1.

Macrophages (MΦs) colonize tissues during inflammation in two distinct ways: recruitment of monocyte precursors and proliferation of resident cells. We recently revealed a major role for IL-4 in the proliferative expansion of resident MΦs during a Th2-biased tissue nematode infection. We now show that proliferation of MΦs during intestinal as well as tissue nematode infection is restricted to sites of IL-4 production and requires MΦ-intrinsic IL-4R signaling.

Induction of IL-4Rα-dependent microRNAs identifies PI3K/Akt signaling as essential for IL-4-driven murine macrophage proliferation in vivo.

Macrophage (MΦ) activation must be tightly controlled to preclude overzealous responses that cause self-damage. MicroRNAs promote classical MΦ activation by blocking antiinflammatory signals and transcription factors but also can prevent excessive TLR signaling. In contrast, the microRNA profile associated with alternatively activated MΦ and their role in regulating wound healing or antihelminthic responses has not been described.