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Biology subjects

Dan, M.

Publications and source records attributed to Dan, M..

2 recordsLinked to original sources

Shank3 mutation disrupts affective touch encoding in the dorsal medial prefrontal cortex of Beagle dogs

Individuals with autism spectrum disorder (ASD) often show aversion to affective touch (AT). However, the neural mechanism of this abnormality in cortices remains poorly understood probably due to the lack of effective animal models. Here, we used a canine model to address this issue by leveraging the intimate dog-human interactions. In a newly-designed heterospecific AT paradigm, we found that dogs carrying mutations in Shank3, a high-risk gene for ASD, avoided human AT. In vivo single-unit recording analysis showed that AT-evoked oscillations in the dorsal medial prefrontal cortex (dmPFC) were significantly altered in Shank3 mutant dogs. Shank3 mutation also reduced the number of neurons encoding AT in the dmPFC. Importantly, the aversion to AT and altered neural processing in Shank3 mutants were largely rescued by a GABAA receptor antagonist pentylenetetrazole. Together, these findings provide neural mechanisms for abnormal AT processing in ASD and suggest potential biomarkers for therapeutic strategies.

neuroscience↗

Islet macrophages are the primary islet source of IGF-1 and improve glucose homeostasis following pancreatic beta-cell death.

Macrophages play a dynamic role in tissue repair following injury. Here we found that following streptozotocin (STZ)-induced beta-cell death, mouse islet macrophages expressed increased Igf1, decreased proinflammatory cytokine expression, and transcriptome changes consistent with macrophages undergoing efferocytosis and having an enhanced state of metabolism. Macrophages were the major, if not sole, contributors to islet IGF-1 production. Adoptive transfer experiments showed that macrophages can maintain insulin secretion in vivo following beta-cell death with no effects on islet-cell turnover. IGF-1 neutralization during STZ-treatment decreased insulin secretion without affecting islet-cell apoptosis or proliferation. Interestingly, high fat diet (HFD) combined with STZ further skewed islet macrophages to a reparative state. Finally, islet macrophages from db/db mice also expressed decreased proinflammatory cytokines and increased Igf1 mRNA. These data have important implications for islet biology and pathology and show that islet macrophages preserve their reparative state following beta-cell death even during HFD feeding and severe hyperglycemia.

immunology↗