Biology subjects

Contreras, J.

Publications and source records attributed to Contreras, J..

2 recordsLinked to original sources

bioRxiv2022

Unbiased stereologic estimates of dopaminergic and GABAergic neurons in the A10, A9, and A8 subpopulations in the young male Macaque

The ventral midbrain is the primary source of dopamine- (DA) expressing neurons in most species. GABA-ergic and glutamatergic cell populations are intermixed among DA-expressing cells and purported to regulate both local and long-range dopamine neuron activity. Most work has been conducted in rodent models, however due to evolutionary expansion of the ventral midbrain in primates, the increased size and complexity of DA subpopulations warrants further investigation. Here, we quantified the number of DA neurons, and their GABA-ergic complement in classic DA cell groups A10 (midline ventral tegmental area nuclei [VTA] and parabrachial pigmented nucleus [PBP]), A9 (substantia nigra, pars compacta [SNc]) and A8 (retrorubral field [RRF]) in the macaque. Because the PBP is a disproportionately expanded feature of the A10 group, and has unique connectional features in monkeys, we analyzed A10 data by dividing it into classic midline nuclei and the PBP. Unbiased stereology revealed total putative DA neuron counts to be 210,238 +/- 17,127 (A10 = 110,319 +/- 9,649, A9= 87,399 +/-7,751 and A8=12,520 +/- 827). Putative GABAergic neurons were fewer overall, and evenly dispersed across the DA subpopulations (GAD67= 71,215 +/- 5,663; A10=16,836 +/- 2,743; A9=24,855 +/- 3,144 and A8=12,633 +/- 3,557). Calculating the GAD67/TH ratio for each subregion revealed differential balances of these two cell types across the DA subregions. The A8 subregion had the highest complement of GAD67-positive neurons compared to TH-positive neurons (1:1), suggesting a potentially high capacity for GABAergic inhibition of DA output in this region. HIGHLIGHTSO_LIThe A10 subregion expands laterally and caudally in nonhuman primates C_LIO_LIThe A10, A9, and A8 comprise 52%, 42% and 6% of DA neurons, respectively C_LIO_LIGABAergic neurons are more evenly dispersed across subregions C_LIO_LIThe A8 subpopulation has the highest ratio of GABA: DA neurons C_LI

neuroscience↗

bioRxiv2021

Neutrophils contribute to ER stress in lung epithelial cells in the pristane-induced diffuse alveolar hemorrhage mouse model

Diffuse alveolar hemorrhage (DAH), although rare, is a life-threatening complication of systemic lupus erythematosus (SLE). Little is known about the pathophysiology of DAH in humans, although increasingly neutrophils, NETosis and inflammatory monocytes have been shown to play an important role in the pristane-induced model of SLE which develops lung hemorrhage and recapitulates many of the pathologic features of human DAH. Using this experimental model, we asked whether endoplasmic reticulum (ER) stress played a role in driving the pathology of pulmonary hemorrhage and what role infiltrating neutrophils had in this process. Analysis of lung tissue from pristane-treated mice showed genes associated with ER stress and NETosis were increased in a time-dependent manner and reflected the timing of CD11b+Ly6G+ neutrophil accumulation in the lung. Using precision cut lung slices from untreated mice we observed that neutrophils isolated from the peritoneal cavity of pristane-treated mice could directly induce the expression of genes associated with ER stress, namely Chop and Bip. Mice which had myeloid-specific deletion of PAD4 were generated and treated with pristane to assess the involvement of PAD4 and PAD4-dependent NET formation in pristane-induced lung inflammation. Specific deletion of PAD4 in myeloid cells resulted in decreased expression of ER stress genes in the pristane model, with accompanying reduction in IFN-driven genes and pathology. Lastly, coculture experiments of human neutrophils and human lung epithelial cell line (BEAS-2b) showed neutrophils from SLE patients induced significantly more ER stress and interferon-stimulated genes in epithelial cells compared to healthy control neutrophils. These results support a pathogenic role of neutrophils and NETs in lung injury during pristane-induced DAH through the induction of ER stress response and suggest that overactivation of neutrophils in SLE and NETosis may underlie development of DAH.

immunology↗