Our recent study revealed that photobiomodulation (PBM) inhibits delayed neuronal death by preserving mitochondrial dynamics and function following global cerebral ischemia (GCI). In the current study, we clarified whether PBM exerts effective roles in endogenous neurogenesis and long-lasting neurological recovery after GCI. Adult male rats were treated with 808 nm PBM at 20 mW/cm2 irradiance for 2 min on cerebral cortex surface (irradiance ∼7.0 mW/cm2, fluence ∼0.8 J/cm2 on the hippocampus) beginning 3 days after GCI for five consecutive days. Cognitive function was evaluated using the Morris water maze. Neural stem cell (NSC) proliferation, immature neurons, and mature neurons were examined using bromodeoxyuridine (BrdU)-, doublecortin (DCX)-, and NeuN-staining, respectively. Protein expression, such as NLRP3, cleaved IL1β, GFAP, and Iba1 was detected using immunofluorescence staining, and ultrastructure of astrocyte and microglia was observed by transmission electron microscopy. The results revealed that PBM exerted a markedly neuroprotective role and improved spatial learning and memory ability at 58 days of ischemia/reperfusion (I/R) but not at 7 days of reperfusion. Mechanistic studies revealed that PBM suppressed reactive astrocytes and maintained astrocyte regeneration at 7 days of reperfusion, as well as elevated neurogenesis at 58 days of reperfusion, as evidenced by a significant decrease in the fluorescence intensity of GFAP (astrocyte marker) but unchanged the number of BrdU-GFAP colabeled cells at the early timepoint, and a robust elevation in the number of DCX-NeuN colabeled cells at the later timepoint in the PBM-treated group compared to the GCI group. Notably, PBM treatment protected the ultrastructure of astrocyte and microglia cells at 58 days but not 7 days of reperfusion in the hippocampal CA1 region. Furthermore, PBM treatment significantly attenuated the GCI-induced immunofluorescence intensity of NLRP3 (an inflammasome component), cleaved IL1β (reflecting inflammasome activation) and Iba1, as well as the colocalization of NLRP3/GFAP or cleaved IL-1β/GFAP, especially in animals subjected to I/R at 58 days. Taken together, PBM treatment performed postischemia exerted a long-lasting protective effect on astrocytes and promoted endogenous neurogenesis in the hippocampal CA1 region, which might contribute to neurological recovery after GCI.

GRP75, defined as a major component of both mitochondrial quality control system and mitochondria-associated membrane, plays a key role in mitochondrial homeostasis. In this study, we assessed the roles of GRP75, other than as a component, in insulin action in both in vitro and in vivo models with insulin resistance. We found that GRP75 was downregulated in HFD-fed mice, and induction of Grp75 in mice could prevent HFD induced obesity and insulin resistance. Mechanistically, GRP75 influenced insulin sensitivity by regulating mitochondrial function through its modulation of mitochondrial-supercomplex turnover rather than MAM communication: GRP75 was negatively associated with respiratory-chain complex activity and was essential for mitochondrial-supercomplex assembly and stabilization. Moreover, mitochondrial dysfunction in Grp75-knockdown cells might further increase mitochondrial fragmentation, thus trigger cytosolic mitochondrial DNA release and activate the cGAS/STING-dependent pro-inflammatory response. Therefore, GRP75 can serve as a potential therapeutic target of insulin resistant-related diabetes or other metabolic diseases.

No abstract

There is a long‐standing prediction that small changes in proliferation and apoptosis during the time frame of facial morphogenesis act to shape the face. Further, many studies show genetic alterations that cause structural birth defects affect local proliferation or apoptosis. Yet, it is unclear how much of local change in regional proliferation would be necessary to cause a defect. Here, we set out to understand the relationship between growth, morphology and proliferation and test that prediction that targeted proliferation shapes the developing face by quantifying proliferation and apoptosis in 3D and relating it to the growth of the face. We use whole mount staining for proliferation and apoptosis markers, whole tissue clearing methods, lightsheet microscopy and atlas and machine learning based quantification methods to identify individual proliferating or apoptotic nuclei within a 3D tissue structure at a set time point. We also employee geometric morphometric analysis of the same tissue structure to quantify overall morphology. By collecting data at various time points across facial development (E9.5–E11.5) and quantifying the age of each embryo, we are able to relate cell biological level growth to tissue level growth and morphological change and relate these two parameters in a way not performed previously. Support or Funding Information NIH NIDCR R01‐DE019638 to RM and BH, NSERC Discovery to BH, and CIHR Foundation grant to BH and RM, CIHR postdoctoral fellowship to RMG. Atlas based quantification of proliferation: A) Maximum Projection of the embryo highlighting the external morphology ‐ lateral view. B) Proliferation staining (phospho‐Histone H3) ‐ lateral view. C–D) Surface morphology of the atlas (n=5) C ‐ anterior view, D ‐ Lateral view. E–F) Heat map of proliferating cells (no density correction) E ‐ anterior view, F ‐ Lateral view.

Epigenetic modifications in A‐strain mice can lead to cleft lip and palate (CLP). All A‐strain mice have a retrotransposon present near the Wnt9b gene, yet, two A‐strain mice cleft at very different rates. A/WySn clefts at 25% while A/J clefts at 5%, yet each line isogenic. The difference in clefting rates is thought to be due to changes in methylation of the retrotransposon. This variation in the penetrance of clefting among strains makes this an interesting model for human orofacial clefting as CLP is also variably penetrant in humans. Here, we test the hypothesis that these mice have subtle variations in 3D cell proliferation and apoptosis that cause variation in the shape of the facial tissues during crucial steps of facial formation, leading to CLP. Further, we predict these changes in proliferation, apoptosis and morphology correlate with Wnt9b levels. Genome changes between related A‐strain mice with different CLP levels also suggest that other loci may be involved in the variable clefting present in these mice. Combined, these results imply that variation in gene expression within a genotype leads to variation in cellular dynamics and the resulting morphogenesis, producing CLP leading to cleft development in a subset of A‐strain mice.Support or Funding InformationNIH NIDCR R01 DE019638 to RS and BH. CIHR Foundation Grant to BH and RS. CIHR Postdoctoral Fellowship to RG.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.