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Additional file 1: Fig. S1. PIEZO1 and PIEZO2 expression in human and mouse RNA‑seq dataset and staining controls for hiMGL immunostaining. Fig. S2. Activation of PIEZO1 orchestrates immune response of human iMGLs. Fig. S3. No differences in PIEZO1 expression in bulk brain tissue between WT and 5xFAD mice. Fig. S4. PIEZO1, microglia, astrocyte and Aβ plaque stainings in 5xFAD hippocampi. Fig. S5. PIEZO1 gene expression in published AD‑related RNA datasets by our analysis. Fig. S6. Characterization of MAD1 and MAD8 iPSC lines. Fig. S7. A diagram visualizing author contribution. Fig. S8. A graphical abstract summarizing the main finding of the paper. Table S1. A correlation data for Piezo1 and the DAM signature genes in microglial subpopulations in Keren-Shaul et al. 2017 dataset [41] (GSE98969). Table S2. A correlation data for Piezo1and the DAM signature genes in microglial subpopulations in Zhou et al. 2021 dataset [42] (GSE140511). Table S3. Differentially expressed genes (DEGs) specific for m1‑subcluster in snRNA Grubman etal. 2019 dataset [40] (GSE138852).

Ischemic stroke, the third leading cause of death in the Western world, affects mainly the elderly and is strongly associated with comorbid conditions such as atherosclerosis or diabetes, which are pathologically characterized by increased inflammation and are known to influence the outcome of stroke. Stroke incidence peaks during influenza seasons, and patients suffering from infections such as pneumonia prior to stroke exhibit a worse stroke outcome. Earlier studies have shown that comorbidities aggravate the outcome of stroke, yet the mediators of this phenomenon remain obscure. Here, we show that acute peripheral inflammation aggravates stroke‐induced neuronal damage and motor deficits specifically in aged mice. This is associated with increased levels of plasma proinflammatory cytokines, rather than with an increase of inflammatory mediators in the affected brain parenchyma. Nascent transcriptomics data with mature microRNA sequencing were used to identify the neuron‐specific miRNome, in order to decipher dysregulated miRNAs in the brains of aged animals with stroke and co‐existing inflammation. We pinpoint a previously uninvestigated miRNA in the brain, miR‐127, that is highly neuronal, to be associated with increased cell death in the aged, LPS‐injected ischemic mice. Target prediction tools indicate that miR‐127 interacts with several basally expressed neuronal genes, and of these we verify miR‐127 binding to Psmd3. Finally, we report reduced expression of miR‐127 in human stroke brains. Our results underline the impact of peripheral inflammation on the outcome of stroke in aged subjects and pinpoint molecular targets for restoring endogenous neuronal capacity to combat ischemic stroke., Peripheral inflammation preceeding ischemic stroke impairs neuronal survival specifically in the elderly. This increased vulnerability is associated with downregulation of the expression of miR‐127, in both animals and humans. Our results reveal novel molecular targets for treating ischemic stroke, and underline the impact of peripheral inflammation on the outcome of stroke in aged subjects.

Additional file 1: Table S1. Cell Line Information. Table S2. Chemical composition of PMs used in this study. Table S3. Taqman assays used in this study. Figure S1. Initial dose response assessment of PM10–2.5 and PM2.5–1.

Additional file 1: Supplementary Figure 1. MiR-669c-3p levels are upregulated in primary murine microglia upon LPS and IFN-γ challenge. LPS or IL-4 exposure alone does not alter BV2 cell (A) or primary microglial cell (B) expression of miR-669c-3p, yet miR-669c-3p expression is induced in primary microglia upon IFN-γ and LPS combined stimulation (M1) (B). Quantitative real-time PCR for miR-669c-3p in wild type BV2 cells treated with vehicle, LPS (50 ng/ml) or IL-4 (20 ng/ml) for 24 h or primary murine microglia treated with vehicle or IFN-γ (20 ng/ml) in combination with LPS (10 ng/ml) for 24 h. One-way ANOVA followed by Bonferroni's post-hoc tests: N = 6-7 in each group. MiR-669c-3p expression is higher in unstimulated primary microglia in comparison to primary astrocytes (C). Quantitative real-time PCR for miR-669c-3p in vehicle-treated primary murine microglia (MG) or vehicle primary murine astrocytes (ASTRO). Unpaired two-tailed t-test: **p < 0.01 compared to vehicle treated astrocytes, N = 3-6. MiR-669c-3p (669) expression is increased in LV1-miR-669c transduced BV2 cells versus LV1-GFP (GFP) transduced cells (D). Quantitative real-time PCR for miR-669c-3p in BV2 cells transduced either with control LV1-GFP or LV1-miR-669c. Unpaired two-tailed t-test: ***p < 0.001 compared to LV1-GFP transduced vehicle, N = 4-6 in each group.

Background/Objective: Stroke is a leading global cause of adult disability. As the population ages as well as suffers co-morbidities, it is expected that the stroke burden will increase further. There are no established safe and effective restorative treatments to facilitate a good functional outcome in stroke patients. Cell-based therapies, which have a wide therapeutic window, might benefit a large percentage of patients, especially if combined with different restorative strategies. In this study, we tested whether the therapeutic effect of human adipose tissue-derived mesenchymal stem cells (ADMSCs) could be further enhanced by rehabilitation in an experimental model of stroke. Methods: Focal cerebral ischemia was induced in adult male Sprague Dawley rats by permanently occluding the distal middle cerebral artery (MCAO). After the intravenous infusion of vehicle (n = 46) or ADMSCs (2 × 106) either at 2 (n = 37) or 7 (n = 7) days after the operation, half of the animals were housed in an enriched environment mimicking rehabilitation. Subsequently, their behavioral recovery was assessed by a neurological score, and performance in the cylinder and sticky label tests during a 42-day behavioral follow-up. At the end of the follow-up, rats were perfused for histology to assess the extent of angiogenesis (RECA-1), gliosis (GFAP), and glial scar formation. Results: No adverse effects were observed during the follow-up. Combined ADMSC therapy and rehabilitation improved forelimb use in the cylinder test in comparison to MCAO controls on post-operative days 21 and 42 (P < 0.01). In the sticky label test, ADMSCs and rehabilitation alone or together, significantly decreased the removal time as compared to MCAO controls on post-operative days 21 and 42. An early initiation of combined therapy seemed to be more effective. Infarct size, measured by MRI on post-operative days 1 and 43, did not differ between the experimental groups. Stereological counting revealed an ischemia-induced increase both in the density of blood vessels and the numbers of glial cells in the perilesional cortex, but there were no differences among MCAO groups. Glial scar volume was also similar in MCAO groups. Conclusion: Early delivery of ADMSCs and combined rehabilitation enhanced behavioral recovery in an experimental stroke model. The mechanisms underlying these treatment effects remain unknown.

Highlights • Th2-type cytokine IL-33 delayed the disease onset of female SOD1-G93 A transgenic ALS mice. • IL-33 decreased the proportion of T cells in the spleens and lymph nodes of female mice. • IL-33 decreased astrocytic activation in the spinal cord of female mice. • Male mice were unresponsive to the treatment., Inflammation is a prominent feature of the neuropathology of amyotrophic lateral sclerosis (ALS). Emerging evidence suggests that inflammatory cascades contributing to the disease progression are not restricted to the central nervous system (CNS) but also occur peripherally. Indeed, alterations in T cell responses and their secreted cytokines have been detected in ALS patients and in animal models of ALS. One key cytokine responsible for the shift in T cell responses is interleukin-33 (IL-33), which stimulates innate type 2 immune cells to produce a large amount of Th2 cytokines that are possibly beneficial in the recovery processes of CNS injuries. Since the levels of IL-33 have been shown to be decreased in patients affected with ALS, we sought to determine whether a long-term recombinant IL-33 treatment of a transgenic mouse model of ALS expressing G93A-superoxide dismutase 1 (SOD1-G93A) alters the disease progression and ameliorates the ALS-like disease pathology. SOD1-G93A mice were treated with intraperitoneal injections of IL-33 and effects on disease onset and inflammatory status were determined. Spinal cord (SC) neurons, astrocytes and T-cells were exposed to IL-33 to evaluate the cell specific responses to IL-33. Treatment of SOD1-G93A mice with IL-33 delayed the disease onset in female mice, decreased the proportion of CD4+ and CD8 + T cell populations in the spleen and lymph nodes, and alleviated astrocytic activation in the ventral horn of the lumbar SC. Male SOD1-G93A mice were unresponsive to the treatment. In vitro studies showed that IL-33 is most likely not acting directly on neurons and astrocytes, but rather conveying its effects through peripheral T-cells. Our results suggest that strategies directed to the peripheral immune system may have therapeutic potential in ALS. The effect of gender dimorphisms to the treatment efficacy needs to be taken into consideration when designing new therapeutic strategies for CNS diseases.