Intravitreal Metformin Protects Against Choroidal Neovascularization and Light-Induced Retinal Degeneration.

Neovascular age-related macular degeneration (nAMD), a leading cause of blindness in older adults, presents a challenging pathophysiology involving choroidal neovascularization (CNV) and retinal degeneration. Current treatments relying on intravitreal (IVT) administration of anti-angiogenic agents are costly and of moderate effectiveness. Metformin, the common anti-diabetic drug, has been associated with decreased odds of developing AMD.

Retinal perivascular macrophages regulate immune cell infiltration during neuroinflammation in mouse models of ocular disease.

The blood-retina barrier (BRB), which is disrupted in diabetic retinopathy (DR) and uveitis, is an important anatomical characteristic of the retina, regulating nutrient, waste, water, protein, and immune cell flux. The BRB is composed of endothelial cell tight junctions, pericytes, astrocyte end feet, a collagen basement membrane, and perivascular macrophages. Despite the importance of the BRB, retinal perivascular macrophage function remains unknown.

Retinal microglia express more MHC class I and promote greater T-cell-driven inflammation than brain microglia.

Introduction: Macrophage function is determined by microenvironment and origin. Brain and retinal microglia are both derived from yolk sac progenitors, yet their microenvironments differ. Utilizing single-cell RNA sequencing (scRNA-seq) data from mice, we tested the hypothesis that retinal and brain microglia exhibit distinct transcriptional profiles due to their unique microenvironments.

NR4A1 deletion promotes pro-angiogenic polarization of macrophages derived from classical monocytes in a mouse model of neovascular age-related macular degeneration.

Background: Neovascular age-related macular degeneration causes vision loss from destructive angiogenesis, termed choroidal neovascularization (CNV). Cx3cr1 mice display alterations in non-classical monocytes and microglia with increased CNV size, suggesting that non-classical monocytes may inhibit CNV formation. NR4A1 is a transcription factor that is necessary for maturation of non-classical monocytes from classical monocytes.

Thrombospondin-1 proteomimetic polymers exhibit anti-angiogenic activity in a neovascular age-related macular degeneration mouse model.

Neovascular age-related macular degeneration (nAMD) is the leading cause of blindness in the developed world. Current therapy includes monthly intraocular injections of anti-VEGF antibodies, which are ineffective in up to one third of patients. Thrombospondin-1 (TSP1) inhibits angiogenesis via CD36 binding, and its down-regulated expression is negatively associated with the onset of nAMD.

CD11c+ macrophages are proangiogenic and necessary for experimental choroidal neovascularization.

Patients with neovascular AMD (nAMD) suffer vision loss from destructive angiogenesis, termed choroidal neovascularization (CNV). Macrophages are found in CNV lesions from patients with nAMD. Additionally, Ccr2-/- mice, which lack classical monocyte-derived macrophages, show reduced CNV size.

Macrophages in close proximity to the vitreoretinal interface are potential biomarkers of inflammation during retinal vascular disease.

Background: Diabetic retinopathy and retinal vein occlusion are vision threatening retinal vascular diseases. Current first-line therapy targets the vascular component, but many patients are treatment-resistant due to unchecked inflammation. Non-invasive inflammatory imaging biomarkers are a significant unmet clinical need for patients.

Macrophage-derived interleukin-6 is necessary and sufficient for choroidal angiogenesis.

Neovascular age-related macular degeneration (nAMD) commonly causes vision loss from aberrant angiogenesis, termed choroidal neovascularization (CNV). Interleukin-6 (IL6) is a pro-inflammatory and pro-angiogenic cytokine that is correlated with AMD progression and nAMD activity. We hypothesize that anti-IL6 therapy is a potential nAMD therapeutic.

Dendritic cells play no significant role in the laser-induced choroidal neovascularization model.

Age-related macular degeneration (AMD) is genetically associated with complement. Dendritic cells (DCs) play key roles during innate and adaptive immunity, and express complement components and their receptors. We investigated ocular DC heterogeneity and the role of DCs in the laser-induced choroidal neovascularization (CNV) model.

Ocular macrophage origin and heterogeneity during steady state and experimental choroidal neovascularization.

Background: Neovascular age-related macular degeneration (nAMD) commonly causes vision loss from aberrant angiogenesis, termed choroidal neovascularization (CNV). Macrophages are heterogeneous cells that are necessary for experimental CNV, present in human CNV samples, and can display diverse functions, which are dependent upon both their origin and tissue microenvironment. Despite these associations, choroidal macrophage heterogeneity remains unexplored.

Digestion of Whole Mouse Eyes for Multi-Parameter Flow Cytometric Analysis of Mononuclear Phagocytes.

The innate immune system plays important roles in ocular pathophysiology including uveitis, diabetic retinopathy, and age-related macular degeneration. Innate immune cells, specifically mononuclear phagocytes, express overlapping cell surface markers, which makes identifying these populations a challenge. Multi-parameter flow cytometry allows for the simultaneous, quantitative analysis of multiple cell surface markers in order to differentiate monocytes, macrophages, microglia, and dendritic cells in mouse eyes.

A Novel Microglia-Specific Transcriptional Signature Correlates With Behavioral Deficits in Neuropsychiatric Lupus.

Neuropsychiatric symptoms of systemic lupus erythematosus (NP-SLE) affect over one-half of SLE patients, yet underlying mechanisms remain largely unknown. We demonstrate that SLE-prone mice (CReCOM) develop NP-SLE, including behavioral deficits prior to systemic autoimmunity, reduced brain volumes, decreased vascular integrity, and brain-infiltrating leukocytes. NP-SLE microglia exhibit numerical expansion, increased synaptic uptake, and a more metabolically active phenotype.

Monocyte-Derived Macrophages Are Necessary for Beta-Adrenergic Receptor-Driven Choroidal Neovascularization Inhibition.

Purpose: Beta-adrenergic receptor (AR) antagonists, like propranolol, inhibit angiogenesis in multiple ocular conditions through an unknown mechanism. We previously showed that propranolol reduces choroidal neovascularization (CNV) by decreasing interleukin-6 levels. Since macrophages are one of the central producers of interleukin-6, we examined whether macrophages are required for propranolol-driven inhibition of choroidal angiogenesis.

Changes in function but not oligomeric size are associated with αB-crystallin lysine substitution.

αB-Crystallin, ubiquitously expressed in many tissues including the ocular lens, is a small heat shock protein that can prevent protein aggregation. A number of post-translation modifications are reported to modify αB-crystallin function. Recent studies have identified αB-crystallin lysine residues are modified by acetylation and ubiquitination.

Nicotinic acetylcholine receptor stimulation impairs epidermal permeability barrier function and recovery and modulates cornified envelope proteins.

Aim: To characterize how nicotinic acetylcholine receptors (nAChRs) influence epidermal barrier function and recovery following prolonged stress or direct nAChR activation or antagonism.

Main Methods: Mice were subjected to psychological stress or treated topically with nAChR agonist or antagonist for 3 days. We assessed barrier permeability and recovery by measuring transepidermal water loss (TEWL) before and after barrier disruption.

Irregular Breathing in Mice following Genetic Ablation of V2a Neurons.

Neural networks called central pattern generators (CPGs) generate repetitive motor behaviors such as locomotion and breathing. Glutamatergic neurons are required for the generation and inhibitory neurons for the patterning of the motor activity associated with repetitive motor behaviors. In the mouse, glutamatergic V2a neurons coordinate the activity of left and right leg CPGs in the spinal cord enabling mice to generate an alternating gait.

Electrophysiological characterization of V2a interneurons and their locomotor-related activity in the neonatal mouse spinal cord.

The V2a class of Chx10-expressing interneurons has been implicated in frequency-dependent control of left-right phase during locomotion in the mouse. We have used the Chx10::CFP mouse line to further investigate the properties and locomotion-related activity of V2a interneurons in the isolated neonatal spinal cord. V2a interneurons can be divided into three classes, based on their tonic, phasic, or delayed-onset responses to step depolarization.

Genetic ablation of V2a ipsilateral interneurons disrupts left-right locomotor coordination in mammalian spinal cord.

The initiation and coordination of activity in limb muscles are the main functions of neural circuits that control locomotion. Commissural neurons connect locomotor circuits on the two sides of the spinal cord, and represent the known neural substrate for left-right coordination. Here we demonstrate that a group of ipsilateral interneurons, V2a interneurons, plays an essential role in the control of left-right alternation.

Phenotype of V2-derived interneurons and their relationship to the axon guidance molecule EphA4 in the developing mouse spinal cord.

The ventral spinal cord consists of interneuron groups arising from distinct, genetically defined, progenitor domains along the dorsoventral axis. Many of these interneuron groups settle in the ventral spinal cord which, in mammals, contains the central pattern generator for locomotion. In order to better understand the locomotor networks, we have used different transgenic mice for anatomical characterization of one of these interneuron groups, called V2 interneurons.

GATA-factor dependence of the multitype zinc-finger protein FOG-1 for its essential role in megakaryopoiesis.

The function of GATA transcription factors in diverse developmental contexts depends in part on physical interaction with cofactors of the Friend of GATA (FOG) family. However, previous studies indicate that FOG-1 may play a GATA-1-independent role in early megakaryopoiesis, suggesting that FOG proteins might act in a GATA factor-independent manner. Here, we have generated mouse knock-in (KI) mutants harboring a critical valine-to-glycine substitution in the amino-terminal zinc fingers of GATA-1 and GATA-2 to ablate FOG interaction.