ROCK1 Mediates Retinal Glial Cell Migration Promoted by Acrolein

ROCK1/2 signaling contributes to corticosteroid-refractory acute graft-versus-host disease

Patients with corticosteroid-refractory acute graft-versus-host disease (aGVHD) have a low one-year survival rate. Identification and validation of novel targetable kinases in patients who experience corticosteroid-refractory-aGVHD may help improve outcomes. Kinase-specific proteomics of leukocytes from patients with corticosteroid-refractory-GVHD identified rho kinase type 1 (ROCK1) as the most significantly upregulated kinase. ROCK1/2 inhibition improved survival and histological GVHD severity in mice and was synergistic with JAK1/2 inhibition, without compromising graft-versus-leukemia-effects. ROCK1/2-inhibition in macrophages or dendritic cells prior to transfer reduced GVHD severity. Mechanistically, ROCK1/2 inhibition or ROCK1 knockdown interfered with CD80, CD86, MHC-II expression and IL-6, IL-1β, iNOS and TNF production in myeloid cells. This was accompanied by impaired T cell activation by dendritic cells and inhibition of cytoskeletal rearrangements, thereby reducing macrophage and DC migration. NF-κB signaling was reduced in myeloid cells following ROCK1/2 inhibition. In conclusion, ROCK1/2 inhibition interferes with immune activation at multiple levels and reduces acute GVHD while maintaining GVL-effects, including in corticosteroid-refractory settings.

Inhibition of Rho kinase (ROCK) impairs cytoskeletal contractility in human Müller glial cells without effects on cell viability, migration, and extracellular matrix production

The epiretinal membrane is a fibrocontractile tissue that forms on the inner surface of the retina, causing visual impairment ranging from mild to severe, and even retinal detachment. Müller glial cells actively participate in the formation of this membrane. Current research is constantly seeking for new therapeutic approaches that aim to prevent or treat cellular dysfunctions involved in the progression of this common fibrosis condition. The Rho GTPases signaling pathway regulates several processes associated with the epiretinal membrane, such as cell proliferation, migration, and contraction. Rho kinase (ROCK), an effector of the RhoA GTPase, is an interesting potential therapeutic target. This study aimed to evaluate the effects of a ROCK inhibitor (Y27632) on human Müller cells viability, growth, cytoskeletal organization, expression of extracellular matrix components, myofibroblast differentiation, migration, and contractility. Müller cells of the MIO-M1 lineage were cultured and treated for different periods with the inhibitor. Viability was evaluated by MTT assay and trypan blue exclusion method, and growth was evaluated by growth curve and BrdU incorporation assay. The actin cytoskeleton was stained with fluorescent phalloidin, intermediate filaments and microtubules were analyzed with immunofluorescence for vimentin and α-tubulin. Gene and protein expression of collagens I and V, laminin and fibronectin were evaluated by rt-PCR and immunofluorescence. Chemotactic and spontaneous cell migration were studied by transwell assay and time-lapse observation of live cells, respectively. Cell contractility was assessed by collagen gel contraction assay. The results showed that ROCK inhibition by Y27632 did not affect cell viability, but decreased cell growth and proliferation after 72 h. There was a change in cell morphology and organization of F-actin, with a reduction in the cell body, disappearance of stress fibers and formation of long, branched cell extensions. Microtubules and vimentin filaments were also affected, possibly because of F-actin alterations. The inhibitor also reduced gene expression and immunoreactivity of smooth muscle α-actin, a marker of myofibroblasts. The expression of extracellular matrix components was not affected by the inhibitor. Chemotactic cell migration showed no significant changes, while cell contractility was substantially reduced. No spontaneous migration of MIO-M1 cells was observed. In conclusion, pharmacological inhibition of ROCK in Müller cells could be a potentially promising approach to treat epiretinal membranes by preventing cell proliferation, contractility and transdifferentiation, without affecting cell viability.

Modulation of cell migration and cell tracking of the gilthead seabream (Sparus aurata) SAF-1 cells by probiotics

Cell migration is an essential process in immunity and wound healing. The in vitro scratch assay was optimized for the SAF-1 cell line, obtained from gilthead seabream (Sparus aurata) fin. In addition, selected cells from the cell front were tracked for detailed individual cell movement and morphological analysis. Modulation of migration and cell tracking of the SAF-1 cell line by probiotics was evaluated. Cells were cultured and incubated for 24 h with three species of extremophilic yeasts [Yarrowia lipolytica (D1 and N6) and Debaryomyces hansenii (CBS004)] and the bacterium Shewanella putrefaciens (known as SpPdp11) and then scratch and cell tracking assays were performed. The results indicated that the forward velocity was significantly (p < 0.05) increased in SAF-1 cells incubated with CBS004 or SpPdp11. However, cell velocity, cumulative distance and Euclidean distance were only significantly increased in SAF-1 cells incubated with SpPdp11. Furthermore, to increase our understanding of the genes involved in cell movement, the expression profile of ten structural proteins (α-1β tubulin, vinculin, focal adhesion kinase type, alpha-2 integrin, tetraspanin, integrin-linked kinase 1, tensin 3, tensin 4, paxillin, and light chain 2) was studied by real time-PCR. The expression of these genes was modulated as a function of the probiotic tested and the results indicate that CBS004 and SpPdp11 increase the movement of SAF-1 cells.

Diet as a Source of Acrolein: Molecular Basis of Aldehyde Biological Activity in Diabetes and Digestive System Diseases

Acrolein, a highly reactive α,β-unsaturated aldehyde, is a compound involved in the pathogenesis of many diseases, including neurodegenerative diseases, cardiovascular and respiratory diseases, diabetes mellitus, and the development of cancers of various origins. In addition to environmental pollution (e.g., from car exhaust fumes) and tobacco smoke, a serious source of acrolein is our daily diet and improper thermal processing of animal and vegetable fats, carbohydrates, and amino acids. Dietary intake is one of the main routes of human exposure to acrolein, which is a major public health concern. This review focuses on the molecular mechanisms of acrolein activity in the context of its involvement in the pathogenesis of diseases related to the digestive system, including diabetes, alcoholic liver disease, and intestinal cancer.

Semaphorin 3A Inhibits Endoplasmic Reticulum Stress Induced by High Glucose in Müller Cells

PURPOSE

This study aimed to explore the effect of the Semaphorin3A (Sema3A)/Neuropilin-1 (Nrp-1) pathway on Müller cell activities and endoplasmic reticulum (ER) stress induced by high glucose (HG) in vitro.

METHODS

The primary Müller cells of C57BL/6J mice were isolated and cultured in normal or high glucose medium. The expression of endogenous Sema3A and its coreceptor Nrp-1 was measured by Western blot. Müller cells were incubated with exogenous recombinant Sema3A protein or transfected with lentiviral vectors expressing small hairpin RNA (shRNA) to knock down the expression of endogenous Sema3A. The proliferation of Müller cells was detected by CCK-8 assay and EdU staining. The migratory ability was detected by the Transwell migration assay. The level of endoplasmic reticulum (ER) stress was analyzed through the detection of GRP78/BiP, IRE1α, phosphorylated IRE1αS724 (p-IRE1αS724), and the splicing rate of XBP1 (XBP1s/XBP1) by using immunofluorescence, Western blot or quantitative polymerase chain reaction (qPCR).

RESULTS

HG induced the upregulation of endogenous Sema3A and Nrp-1 receptors in Müller cells. The expression of GRP78/BiP and IRE1α was upregulated by HG, with an increased splicing rate of XBP1. Exogenous Sema3A inhibited HG-induced Müller cell proliferation, migration, and GRP78/BiP-IRE1α-XBP1 axis activation. Knockdown of Sema3A promoted proliferation, migration, and ER stress induced by high glucose in Müller cells.

CONCLUSION

Sema3A inhibited the increased proliferative and migratory activities induced by high glucose by attenuating ER stress in Müller cells.

Acrolein, an endogenous aldehyde induces synaptic dysfunction in vitro and in vivo: Involvement of RhoA/ROCK2 pathway

Acrolein, an unsaturated aldehyde, is increased in the brain of Alzheimer's disease (AD) patients and identified as a potential inducer of sporadic AD. Synaptic dysfunction, as a typical pathological change occurring in the early stage of AD, is most closely associated with the severity of dementia. However, there remains a lack of clarity on the mechanisms of acrolein inducing AD-like pathology and synaptic impairment. In this study, acrolein-treated primary cultured neurons and mice were applied to investigate the effects of acrolein on cognitive impairment and synaptic dysfunction and their signaling mechanisms. In vitro, ROCK inhibitors, Fasudil, and Y27632, could attenuate the axon ruptures and synaptic impairment caused by acrolein. Meanwhile, RNA-seq distinct differentially expressed genes in acrolein models and initially linked activated RhoA/Rho-kinase2 (ROCK2) to acrolein-induced synaptic dysfunction, which could regulate neuronal cytoskeleton and neurite. The Morris water maze test and in vivo field excitatory postsynaptic potential (fEPSP) were performed to evaluate spatial memory and long-term potential (LTP), respectively. Acrolein induced cognitive impairment and attenuated LTP. Furthermore, the protein level of Synapsin 1 and postsynaptic density 95 (PSD95) and dendritic spines density were also decreased in acrolein-exposed mice. These changes were improved by ROCK2 inhibitor Fasudil or in ROCK2^+/- mice. Together, our findings suggest that RhoA/ROCK2 signaling pathway plays a critical role in acrolein-induced synaptic damage and cognitive dysfunction, suggesting inhibition of ROCK2 should benefit to the early AD.