Regulation of C3 Activation by the Alternative Complement Pathway in the Mouse Retina

Genetic Insights into Age-Related Macular Degeneration

One of the major causes of vision impairment among elderly people in developed nations is age-related macular degeneration (AMD). The distinctive features of AMD are the accumulation of extracellular deposits called drusen and the gradual deterioration of photoreceptors and nearby tissues in the macula. AMD is a complex and multifaceted disease influenced by several factors such as aging, environmental risk factors, and a person's genetic susceptibility to the condition. The interaction among these factors leads to the initiation and advancement of AMD, where genetic predisposition plays a crucial role. With the advent of high-throughput genotyping technologies, many novel genetic loci associated with AMD have been identified, enhancing our knowledge of its genetic architecture. The common genetic variants linked to AMD are found on chromosome 1q32 (in the complement factor H gene) and 10q26 (age-related maculopathy susceptibility 2 and high-temperature requirement A serine peptidase 1 genes) loci, along with several other risk variants. This review summarizes the common genetic variants of complement pathways, lipid metabolism, and extracellular matrix proteins associated with AMD risk, highlighting the intricate pathways contributing to AMD pathogenesis. Knowledge of the genetic underpinnings of AMD will allow for the future development of personalized diagnostics and targeted therapeutic interventions, paving the way for more effective management of AMD and improved outcomes for affected individuals.

Transcriptome analysis of AAV-induced retinopathy models expressing human VEGF, TNF-α, and IL-6 in murine eyes

Retinopathies are multifactorial diseases with complex pathologies that eventually lead to vision loss. Animal models facilitate the understanding of the pathophysiology and identification of novel treatment options. However, each animal model reflects only specific disease aspects and understanding of the specific molecular changes in most disease models is limited. Here, we conducted transcriptome analysis of murine ocular tissue transduced with recombinant Adeno-associated viruses (AAVs) expressing either human VEGF-A, TNF-α, or IL-6. VEGF expression led to a distinct regulation of extracellular matrix (ECM)-associated genes. In contrast, both TNF-α and IL-6 led to more comparable gene expression changes in interleukin signaling, and the complement cascade, with TNF-α-induced changes being more pronounced. Furthermore, integration of single cell RNA-Sequencing data suggested an increase of endothelial cell-specific marker genes by VEGF, while TNF-α expression increased the expression T-cell markers. Both TNF-α and IL-6 expression led to an increase in macrophage markers. Finally, transcriptomic changes in AAV-VEGF treated mice largely overlapped with gene expression changes observed in the oxygen-induced retinopathy model, especially regarding ECM components and endothelial cell-specific gene expression. Altogether, our study represents a valuable investigation of gene expression changes induced by VEGF, TNF-α, and IL-6 and will aid researchers in selecting appropriate animal models for retinopathies based on their agreement with the human pathophysiology.

Transcriptomics Analysis Reveals the Immune Response Mechanism of Rabbits with Diarrhea Fed an Antibiotic-Free Diet

Simple Summary

Feeding an antibiotic-free diet is an inevitable trend in animal husbandry in China. In this study, high-throughput sequencing was used to analyze the gene expression differences in various intestinal segments of rabbits. Our analysis identified 168, 593, 2069, 334, 321, and 1423 DEGs in the comparison groups S_Z (the duodenum of healthy rabbits) vs. S_B (diarrhea in the duodenum of rabbits), K_Z (healthy rabbit jejunum) vs. K_B (rabbits with diarrhea in the jejunum), H_Z (healthy rabbit ileum) vs. H_B (rabbits with diarrhea in the ileum), M_Z (healthy cecum of rabbits) vs. M_B (rabbit with diarrhea in the cecum), J_Z (healthy rabbit colon) vs. J_B (colon of rabbits with diarrhea), and Z_Z (healthy rabbit rectum) vs. Z_B (rectum of rabbits with diarrhea), respectively. The reproducibility and repeatability of the results were validated by RT-qPCR. Enrichment analyses of GO annotations and KEGG pathways revealed the host DEGs that are potentially related to acute inflammation, stress response, tissue dehydration, adaptive immune response, protein binding, activation of related enzymes, migration of immune cells, and so on. In this descriptive study, our findings revealed the changes in the host transcriptome expression profile while feeding an antibiotic-free diet and suggested that feeding an antibiotic-free diet alters the host’s metabolic network and the expression of antiviral proteins.

Abstract

China officially promulgated the announcement of banning the use of antibiotics in the animal industry in 2020. However, the prohibition of antibiotics in the animal industry would reduce the feed conversion rate and increase the mortality of animals. In order to obtain information about the pathogenesis and host immune response of rabbits with diarrhea after being fed an antibiotic-free diet, we first analyzed the intestinal tissue sections of rabbits. Secondly, the gene expression differences of rabbit intestinal segments were analyzed by high-throughput sequencing. Our analysis identified 168, 593, 2069, 334, 321, and 1423 DEGs in the comparison groups S_Z (the duodenum of healthy rabbits) vs. S_B (diarrhea in the duodenum of rabbits), K_Z (healthy rabbit jejunum) vs. K_B (rabbits with diarrhea in the jejunum), H_Z (healthy rabbit ileum) vs. H_B (rabbits with diarrhea in the ileum), M_Z (healthy cecum of rabbits) vs. M_B (rabbits with diarrhea in the cecum), J_Z (healthy rabbit colon) vs. J_B (colon of rabbits with diarrhea), and Z_Z (healthy rabbit rectum) vs. Z_B (rectum of rabbits with diarrhea), respectively. The reproducibility and repeatability of the results were validated by RT-qPCR. Enrichment analyses of GO annotations and KEGG pathways revealed the host DEGs that are potentially related to acute inflammation, stress response, tissue dehydration, adaptive immune response, protein binding, activation of related enzymes, migration of immune cells, and so on. In this descriptive study, our findings revealed the changes in the host transcriptome expression profile after feeding an antibiotic-free diet and suggested that feeding an antibiotic-free diet alters the host’s metabolic network and the expression of antiviral proteins, which provides a theoretical basis for further study on the immune response of animals fed an antibiotic-free diet.

Glaucoma and neuroinflammation: An overview

Glaucoma is an optic neuropathy characterized by well-defined optic disc morphological changes (i.e., cup enlargement, neuroretinal border thinning, and notching, papillary vessel modifications) consequent to retinal ganglion cell loss, axonal degeneration, and lamina cribrosa remodeling. These modifications tend to be progressive and are the main cause of functional damage in glaucoma. Despite the latest findings about the pathophysiology of the disease, the exact trigger mechanisms and the mechanism of degeneration of retinal ganglion cells and their axons have not been completely elucidated. Neuroinflammation may play a role in both the development and the progression of the disease as a result of its effects on retinal environment and retinal ganglion cells. We summarize the latest findings about neuroinflammation in glaucoma and examine the connection between risk factors, neuroinflammation, and retinal ganglion cell degeneration.