Peripherally misfolded proteins exacerbate ischemic stroke-induced neuroinflammation and brain injury.

BACKGROUND: Protein aggregates can be found in peripheral organs, such as the heart, kidney, and pancreas, but little is known about the impact of peripherally misfolded proteins on neuroinflammation and brain functional recovery following ischemic stroke. METHODS: Here, we studied the ischemia/reperfusion (I/R) induced brain injury in mice with cardiomyocyte-restricted overexpression of a missense (R120G) mutant small heat shock protein, αB-crystallin (CryABR120G), by examining neuroinflammation and brain functional recovery following I/R in comparison to their non-transgenic (Ntg) littermates. To understand how peripherally misfolded proteins influence brain functionality, exosomes were isolated from CryABR120G and Ntg mouse blood and were used to treat wild-type (WT) mice and primary cortical neuron-glia mix cultures. Additionally, isolated protein aggregates from the brain following I/R were isolated and subjected to mass-spectrometric analysis to assess whether the aggregates contained the mutant protein, CryABR120G. To determine whether the CryABR120G misfolding can self-propagate, a misfolded protein seeding assay was performed in cell cultures. RESULTS: Our results showed that CryABR120G mice exhibited dramatically increased infarct volume, delayed brain functional recovery, and enhanced neuroinflammation and protein aggregation in the brain following I/R when compared to the Ntg mice. Intriguingly, mass-spectrometric analysis of the protein aggregates isolated from CryABR120G mouse brains confirmed presence of the mutant CryABR120G protein in the brain. Importantly, intravenous administration of WT mice with the exosomes isolated from CryABR120G mouse blood exacerbated I/R-induced cerebral injury in WT mice. Moreover, incubation of the CryABR120G mouse exosomes with primary neuronal cultures induced pronounced protein aggregation. Transduction of CryABR120G aggregate seeds into cell cultures caused normal CryAB proteins to undergo dramatic aggregation and form large aggregates, suggesting self-propagation of CryABR120G misfolding in cells. CONCLUSIONS: These results suggest that peripherally misfolded proteins in the heart remotely enhance neuroinflammation and exacerbate brain injury following I/R likely through exosomes, which may represent an underappreciated mechanism underlying heart-brain crosstalk.

NeuroMotion smartphone application for remote General Movements Assessment: a feasibility study in Nepal.

OBJECTIVES: To evaluate the feasibility of using the NeuroMotion smartphone application for remote General Movements Assessment for screening infants for cerebral palsy in Kathmandu, Nepal. METHOD: Thirty-one term-born infants at risk of cerebral palsy due to birth asphyxia or neonatal seizures were recruited for the follow-up at Paropakar Maternity and Women's Hospital, 1 October 2021 to 7 January 2022. Parents filmed their children at home using the application at 3 months' age and the videos were assessed for technical quality using a standardised form and for fidgety movements by Prechtl's General Movements Assessment. The usability of the application was evaluated through a parental survey. RESULTS: Twenty families sent in altogether 46 videos out of which 35 had approved technical quality. Sixteen children had at least one video with approved technical quality. Three infants lacked fidgety movements. The level of agreement between assessors was acceptable (Krippendorf alpha 0.781). Parental answers to the usability survey were in general positive. INTERPRETATION: Engaging parents in screening of cerebral palsy with the help of a smartphone-aided remote General Movements Assessment is possible in the urban area of a South Asian lower middle-income country.

Distinguishing Keratoacanthoma from Well-Differentiated Cutaneous Squamous Cell Carcinoma Using Single-Cell Spatial Pathology.

Keratoacanthoma (KA) is a common keratinocyte neoplasm that is regularly classified as a type of cutaneous squamous cell carcinoma (cSCC) despite demonstrating benign behavior. Differentiating KA from well-differentiated cSCC is difficult in many cases due to the substantial overlap of clinical and histological features. Currently, no reliable discriminating markers have been defined, and consequently, KAs are often treated similarly to cSCC, creating unnecessary surgical morbidity and healthcare costs. In this study, we used RNA sequencing to identify key differences in transcriptomes between KA and cSCC, which suggested divergent keratinocyte populations between each tumor. Imaging mass cytometry was then used to identify single-cell tissue characteristics, including cellular phenotype, frequency, topography, functional status, and interactions between KA and well-differentiated cSCC. We found that cSCC had significantly increased proportions of Ki67+ keratinocytes among tumor keratinocytes, which were dispersed significantly throughout non-basal keratinocyte communities. In cSCC, regulatory T-cells were more prevalent and held greater suppressive capacity. Furthermore, cSCC regulatory T-cells, tumor-associated macrophages, and fibroblasts had significant associations with Ki67+ keratinocytes as opposed to avoidances with KA, indicating a more immunosuppressive environment. Our data suggest that multicellular spatial features can serve as a foundation to enhance the histological discrimination of ambiguous KA and cSCC lesions.

Expression of LIM domain-binding 3 (LDB3), a striated muscle Z-band alternatively spliced PDZ-motif protein in the nervous system.

LIM domain-binding 3 (LDB3) is a member of the Enigma family of PDZ-LIM proteins. LDB3 has been reported as a striated muscle-specific Z-band alternatively spliced protein that plays an important role in mechanosensory actin cytoskeleton remodeling. This study shows that LDB3 is broadly expressed in the central and peripheral nervous system of human and mouse. LDB3 is predominantly expressed in the adult stages compared to early development and at a significantly higher level in the spinal cord than in the brain. As in skeletal muscle and heart, LDB3 is extensively alternatively spliced in the neurons. Three novel splice isoforms were identified suggesting splicing-dependent regulation of LDB3 expression in the nervous system. Expression of LDB3 in the motor cortex, cerebellum, spinal motor neuron, peripheral nerve, and neuromuscular junction in addition to skeletal muscle indicates important roles for this PDZ-LIM family protein in motor planning and execution. Moreover, expression in the hippocampal neurons suggests roles for LDB3 in learning and memory. LDB3 interactors filamin C and myotilin are also expressed in the spinal motor neuron, nerve, and neuromuscular junction, thereby providing the basis for neurogenic manifestations in myopathies associated with mutations in these so-called muscle proteins.

Integrative scATAC-seq and scRNA-seq analyses map thymic iNKT cell development and identify Cbfß for its commitment.

Unlike conventional αßT cells, invariant natural killer T (iNKT) cells complete their terminal differentiation to functional iNKT1/2/17 cells in the thymus. However, underlying molecular programs that guide iNKT subset differentiation remain unclear. Here, we profiled the transcriptomes of over 17,000 iNKT cells and the chromatin accessibility states of over 39,000 iNKT cells across four thymic iNKT developmental stages using single-cell RNA sequencing (scRNA-seq) and single-cell assay for transposase-accessible chromatin sequencing (scATAC-seq) to define their developmental trajectories. Our study discovered novel features for iNKT precursors and different iNKT subsets and indicated that iNKT2 and iNKT17 lineage commitment may occur as early as stage 0 (ST0) by two distinct programs, while iNKT1 commitments may occur post ST0. Both iNKT1 and iNKT2 cells exhibit extensive phenotypic and functional heterogeneity, while iNKT17 cells are relatively homogenous. Furthermore, we identified that a novel transcription factor, Cbfß, was highly expressed in iNKT progenitor commitment checkpoint, which showed a similar expression trajectory with other known transcription factors for iNKT cells development, Zbtb16 and Egr2, and could direct iNKT cells fate and drive their effector phenotype differentiation. Conditional deletion of Cbfß blocked early iNKT cell development and led to severe impairment of iNKT1/2/17 cell differentiation. Overall, our findings uncovered distinct iNKT developmental programs as well as their cellular heterogeneity, and identified a novel transcription factor Cbfß as a key regulator for early iNKT cell commitment.

scRNA-Seq and imaging mass cytometry analyses unveil iNKT cells-mediated anti-tumor immunity in pancreatic cancer liver metastasis.

Invariant natural killer T (iNKT) cells are innate-like T cells that are abundant in liver sinusoids and play a critical role in tumor immunity. However, the role of iNKT cells in pancreatic cancer liver metastasis (PCLM) has not been fully explored. In this study, we employed a hemi-spleen pancreatic tumor cell injection mouse model of PCLM, a model that closely mimics clinical conditions in humans, to explore the role of iNKT cells in PCLM. Activation of iNKT cells with α-galactosylceramide (αGC) markedly increased immune cell infiltration and suppressed PCLM progression. Via single cell RNA sequencing (scRNA-seq) we profiled over 30,000 immune cells from normal liver and PCLM with or without αGC treatment and were able to characterize the global changes of the immune cells in the tumor microenvironment upon αGC treatment, identifying a total of 12 subpopulations. Upon treatment with αGC, scRNA-Seq and flow cytometry analyses revealed increased cytotoxic activity of iNKT/NK cells and skewing CD4 T cells towards a cytotoxic Th1 profile and CD8 T cells towards a cytotoxic profile, characterized by higher proliferation and reduced exhaustion marker PD1 expression. Moreover, αGC treatment excluded tumor associated macrophages. Lastly, imaging mass cytometry analysis uncovered the reduced epithelial to mesenchymal transition related markers and increased active CD4 and CD8 T cells in PCLM with αGC treatment. Overall, our findings uncover the protective function of activated iNKT cells in pancreatic cancer liver metastasis through increased NK and T cell immunity and decreased tumor associated macrophages.

Dysregulated CD38 expression in blood and skin immune cells of patients with hidradenitis suppurativa.

Hidradenitis suppurativa (HS) is a multifactorial, inflammatory skin disease. Increased systemic inflammatory comorbidities and serum cytokines highlight systemic inflammation as a feature of HS. However, the specific immune cell subsets contributing to systemic and cutaneous inflammation have not been resolved. Here, we generated whole-blood immunomes by mass cytometry. We performed a meta-analysis of RNA-seq data, immunohistochemistry, and imaging mass cytometry to characterize the immunological landscape of skin lesions and perilesions from patients with HS. Blood from patients with HS exhibited lower frequencies of natural killer cells, dendritic cells, and classical (CD14+CD16-) and nonclassical (CD14-CD16+) monocytes, as well as higher frequencies of Th17 cells and intermediate (CD14+CD16+) monocytes than blood from healthy controls. Classical and intermediate monocytes from patients with HS had increased expression of skin-homing chemokine receptors. Furthermore, we identified a CD38+ intermediate monocyte subpopulation that was more abundant in the immunome of blood from patients with HS. Meta-analysis of RNA-seq data found higher CD38 expression in lesional HS skin than in perilesional skin, and markers of classical monocyte infiltration. Imaging mass cytometry showed that CD38+ classical monocytes and CD38+ monocyte-derived macrophages were more abundant in lesional HS skin. Overall, we report targeting CD38 may be worth pursuing in clinical trials.

Dysregulated CD38 expression in blood and skin immune cells of patients with hidradenitis suppurativa.

Background: Hidradenitis suppurativa (HS) is a multifactorial, inflammatory skin disease. Increased systemic inflammatory comorbidities and serum cytokines highlight systemic inflammation as a feature of HS. However, the specific immune cell subsets contributing to systemic and cutaneous inflammation have not been resolved. Objective: Identify features of peripheral and cutaneous immune dysregulation. Methods: Here, we generated whole-blood immunomes by mass cytometry. We performed a meta-analysis of RNA-seq data, immunohistochemistry, and imaging mass cytometry to characterize the immunological landscape of skin lesions and perilesions from patients with HS. Results: Blood from patients with HS exhibited lower frequencies of natural killer cells, dendritic cells, and classical (CD14+CD16-) and nonclassical (CD14-CD16+) monocytes, as well as higher frequencies of Th17 cells and intermediate (CD14+CD16+) monocytes than blood from healthy controls. Classical and intermediate monocytes from patients with HS had increased expression of skin-homing chemokine receptors. Furthermore, we identified a CD38+ intermediate monocyte subpopulation that was more abundant in the immunome of blood from patients with HS. Meta-analysis of RNA-seq data found higher CD38 expression in lesional HS skin than in perilesional skin, and markers of classical monocyte infiltration. Imaging mass cytometry showed that CD38+ classical monocytes and CD38+ monocyte-derived macrophages were more abundant in lesional HS skin. Conclusion: Overall, we report targeting CD38 may be worth pursuing in clinical trials. Key Messages: 3.Monocyte subsets express markers of activation in circulation and HS lesionsTargeting CD38 may be a viable strategy for treating systemic and cutaneous inflammation in patients with HS. Capsule Summary: 4.Dysregulated immune cells in patients with HS express CD38 and may be targeting by anti-CD38 immunotherapy.

Krüppel-like factor 4 (KLF4) directly regulates proliferation in thymocyte development and IL-17 expression during Th17 differentiation.

Krüppel-like factor 4 (KLF4), a transcription factor, plays a key role in the pluripotency of stem cells. We sought to determine the function of KLF4 in T-cell development and differentiation by using T-cell-specific Klf4-knockout (KO) mice. We found that KLF4 was highly expressed in thymocytes and mature T cells and was rapidly down-regulated in mature T cells after activation. In Klf4-KO mice, we observed a modest reduction of thymocytes (27%) due to the reduced proliferation of double-negative (DN) thymocytes. We demonstrated that a direct repression of Cdkn1b by KLF4 was a cause of decreased DN proliferation. During in vitro T-cell differentiation, we observed significant reduction of IL-17-expressing CD4(+) T cells (Th17; 24%) but not in other types of Th differentiation. The reduction of Th17 cells resulted in a significant attenuation of the severity (35%) of experimental autoimmune encephalomyelitis in vivo in Klf4-KO mice as compared with the Klf4 wild-type littermates. Finally, we demonstrated that KLF4 directly binds to the promoter of Il17a and positively regulates its expression. In summary, these findings identify KLF4 as a critical regulator in T-cell development and Th17 differentiation.

Conditional and Synthetic Type IV Pili-Dependent Motility Phenotypes in Myxococcus xanthus.

Myxobacteria exhibit a variety of complex social behaviors that all depend on coordinated movement of cells on solid surfaces. The cooperative nature of cell movements is known as social (S)-motility. This system is powered by cycles of type IV pili (Tfp) extension and retraction. Exopolysaccharide (EPS) also serves as a matrix to hold cells together. Here, we characterized a new S-motility gene in Myxococcus xanthus. This mutant is temperature-sensitive (Ts-) for S-motility; however, Tfp and EPS are made. A 1 bp deletion was mapped to the MXAN_4099 locus and the gene was named sglS. Null mutations in sglS exhibit a synthetic enhanced phenotype with a null sglT mutation, a previously characterized S-motility gene that exhibits a similar Ts- phenotype. Our results suggest that SglS and SglT contribute toward Tfp function at high temperatures in redundant pathways. However, at low temperatures only one pathway is necessary for wild-type S-motility, while in the double mutant, motility is nearly abolished at low temperatures. Interestingly, the few cells that do move do so with a high reversal frequency. We suggest SglS and SglT play conditional roles facilitating Tfp retraction and hence motility in M. xanthus.

Single-cell analysis reveals differences among iNKT cells colonizing peripheral organs and identifies Klf2 as a key gene for iNKT emigration.

Invariant natural killer T cell (iNKT) subsets are differentially distributed in various immune organs. However, it remains unclear whether iNKT cells exhibit phenotypical and functional differences in different peripheral organs and how thymic iNKT cells emigrate to peripheral organs. Here, we used single-cell RNA-seq to map iNKT cells from peripheral organs. iNKT1 cells from liver, spleen, and lymph node appear to have distinct phenotypic profiles and functional capabilities. However, iNKT17 transcriptomes were comparable across peripheral organs. In addition, by integrating data with a thymic iNKT cell study, we uncovered a transient population of recent thymic emigrants, a cluster of peripheral iNKT cells with high expression of transcription factor Kruppel-like factor 2 (Klf2). Deletion of Klf2 led to a severe impairment of iNKT differentiation and migration. Our study revealed that iNKT subsets are uniquely distributed in peripheral organs with some inter-local tissue variation, especially for iNKT1 cell, and identified Klf2 as a rheostat for iNKT cell migration and differentiation.

Surface translocation of ACE2 and TMPRSS2 upon TLR4/7/8 activation is required for SARS-CoV-2 infection in circulating monocytes.

Infection of human peripheral blood cells by SARS-CoV-2 has been debated because immune cells lack mRNA expression of both angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease type 2 (TMPRSS2). Herein we demonstrate that resting primary monocytes harbor abundant cytoplasmic ACE2 and TMPRSS2 protein and that circulating exosomes contain significant ACE2 protein. Upon ex vivo TLR4/7/8 stimulation, cytoplasmic ACE2 was quickly translocated to the monocyte cell surface independently of ACE2 transcription, while TMPRSS2 surface translocation occurred in conjunction with elevated mRNA expression. The rapid translocation of ACE2 to the monocyte cell surface was blocked by the endosomal trafficking inhibitor endosidin 2, suggesting that endosomal ACE2 could be derived from circulating ACE2-containing exosomes. TLR-stimulated monocytes concurrently expressing ACE2 and TMPRSS2 on the cell surface were efficiently infected by SARS-CoV-2, which was significantly mitigated by remdesivir, TMPRSS2 inhibitor camostat, and anti-ACE2 antibody. Mass cytometry showed that ACE2 surface translocation in peripheral myeloid cells from patients with severe COVID-19 correlated with its hyperactivation and PD-L1 expression. Collectively, TLR4/7/8-induced ACE2 translocation with TMPRSS2 expression makes circulating monocytes permissive to SARS-CoV-2 infection.

Elevated levels of uterine anti-apoptotic signaling may activate NFKB and potentially confer resistance to caspase 3-mediated apoptotic cell death during pregnancy in mice.

Preserving the uterus in a state of relative quiescence is vital to the maintenance of a successful pregnancy. Elevated cytoplasmic levels of uterine caspase 3 during pregnancy have been proposed as a potential regulator of uterine quiescence through direct targeting and disabling of the uterine contractile architecture. However, despite highly elevated levels of uterine caspase 3 during pregnancy, there is minimal evidence of apoptosis. This current study defines the mechanism whereby the pregnant uterine myocyte may harness the tocolytic activity of active caspases while avoiding apoptotic cell death. Using the pregnant mouse model, we have analyzed the uterus for changes in pro- and antiapoptotic signaling patterns associated with the advancing stages of pregnancy. Briefly, we have found that members of the IAP family, such as SURVIVIN and XIAP, and the Bcl2 family members, such as MCL1, are elevated in the uterine myocyte during late gestation. The IAP family members are the only endogenous inhibitors of active caspase 3, and MCL1 limits activation of caspase 3 by suppressing proapoptotic signaling. Elevated XIAP levels partner with SURVIVIN, resulting in increased levels of the antiapoptotic MCL1 via NFKB activation; these together have the potential to limit both the activity and level of active caspase 3 in the pregnant uterus as term approaches. We propose that modification of these antiapoptotic signaling partners allows the pregnant uterus to escape the apoptotic action of elevated active caspase 3 levels but also functions to limit the levels of active uterine caspase 3 near term.

MicroRNA-155 Regulates MAIT1 and MAIT17 Cell Differentiation.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that develop in the thymus through three maturation stages to acquire effector function and differentiate into MAIT1 (T-bet+) and MAIT17 (RORγt+) subsets. Upon activation, MAIT cells release IFN-γ and IL-17, which modulate a broad spectrum of diseases. Recent studies indicate defective MAIT cell development in microRNA deficient mice, however, few individual miRNAs have been identified to regulate MAIT cells. MicroRNA-155 (miR-155) is a key regulator of numerous cellular processes that affect some immune cell development, but its role in MAIT cell development remains unclear. To address whether miR-155 is required for MAIT cell development, we performed gain-of-function and loss-of-function studies. We first generated a CD4Cre.miR-155 knock-in mouse model, in which miR-155 is over-expressed in the T cell lineage. We found that overexpression of miR-155 significantly reduced numbers and frequencies of MAIT cells in all immune organs and lungs and blocked thymic MAIT cell maturation through downregulating PLZF expression. Strikingly, upregulated miR-155 promoted MAIT1 differentiation and blocked MAIT17 differentiation, and timely inducible expression of miR-155 functionally inhibited peripheral MAIT cells secreting IL-17. miR-155 overexpression also increased CD4-CD8+ subset and decreased CD4-CD8- subset of MAIT cells. We further analyzed MAIT cells in conventional miR-155 knockout mice and found that lack of miR-155 also promoted MAIT1 differentiation and blocked MAIT17 differentiation but without alteration of their overall frequency, maturation and function. Overall, our results indicate that adequate miR-155 expression is required for normal MAIT1 and MAIT17 cell development and function.

Emergent Myxobacterial Behaviors Arise from Reversal Suppression Induced by Kin Contacts.

A wide range of biological systems, from microbial swarms to bird flocks, display emergent behaviors driven by coordinated movement of individuals. To this end, individual organisms interact by recognizing their kin and adjusting their motility based on others around them. However, even in the best-studied systems, the mechanistic basis of the interplay between kin recognition and motility coordination is not understood. Here, using a combination of experiments and mathematical modeling, we uncover the mechanism of an emergent social behavior in Myxococcus xanthus. By overexpressing the cell surface adhesins TraA and TraB, which are involved in kin recognition, large numbers of cells adhere to one another and form organized macroscopic circular aggregates that spin clockwise or counterclockwise. Mechanistically, TraAB adhesion results in sustained cell-cell contacts that trigger cells to suppress cell reversals, and circular aggregates form as the result of cells' ability to follow their own cellular slime trails. Furthermore, our in silico simulations demonstrate a remarkable ability to predict self-organization patterns when phenotypically distinct strains are mixed. For example, defying naive expectations, both models and experiments found that strains engineered to overexpress different and incompatible TraAB adhesins nevertheless form mixed circular aggregates. Therefore, this work provides key mechanistic insights into M. xanthus social interactions and demonstrates how local cell contacts induce emergent collective behaviors by millions of cells. IMPORTANCE In many species, large populations exhibit emergent behaviors whereby all related individuals move in unison. For example, fish in schools can all dart in one direction simultaneously to avoid a predator. Currently, it is impossible to explain how such animals recognize kin through brain cognition and elicit such behaviors at a molecular level. However, microbes also recognize kin and exhibit emergent collective behaviors that are experimentally tractable. Here, using a model social bacterium, we engineer dispersed individuals to organize into synchronized collectives that create emergent patterns. With experimental and mathematical approaches, we explain how this occurs at both molecular and population levels. The results demonstrate how the combination of local physical interactions triggers intracellular signaling, which in turn leads to emergent behaviors on a population scale.

Effect of Delayed Cord Clamping on Neurodevelopment at 3 Years: A Randomized Controlled Trial.

INTRODUCTION: Iron deficiency (ID) is associated with poor neurodevelopment. We have previously shown that delayed umbilical cord clamping (CC) improves iron stores at 8 months and neurodevelopment at 1 year in term, healthy infants in Nepal. OBJECTIVE: The aim of this study was to assess the effects of delayed CC (≥180 s) compared to early CC (≤60 s) on neurodevelopment using the Ages and Stages Questionnaire (ASQ) at age 3 years. METHODS: In 2014, 540 healthy Nepalese infants born at term were randomized in a 1:1 ratio to delayed or early CC. At 3 years of age, ASQ assessment was performed by phone interviews with parents. A score >1 standard deviation below the mean was defined as "at risk" for developmental impairment. RESULTS: At 3 years of age, 350 children were followed up, 170 (63.0%) in the early CC group and 180 (66.7%) in the delayed CC group. No significant differences in ASQ scores in any domains between groups were found. However, more girls were "at risk" for affected gross motor development in the early CC group: 14 (18.9%) versus 6 (6.3%), p = 0.02. CONCLUSION: There were no significant differences in ASQ scores in any domains between groups. In the subgroup analysis, fewer girls who underwent delayed CC were "at risk" for delayed gross motor development. Due to the pronounced difference in iron stores at 8 months postpartum in this cohort, follow-up studies at an older age are motivated since neurodevelopmental impairment after early ID may be more detectable with increasing age.

Myopathy associated LDB3 mutation causes Z-disc disassembly and protein aggregation through PKCα and TSC2-mTOR downregulation.

Mechanical stress induced by contractions constantly threatens the integrity of muscle Z-disc, a crucial force-bearing structure in striated muscle. The PDZ-LIM proteins have been proposed to function as adaptors in transducing mechanical signals to preserve the Z-disc structure, however the underlying mechanisms remain poorly understood. Here, we show that LDB3, a well-characterized striated muscle PDZ-LIM protein, modulates mechanical stress signaling through interactions with the mechanosensing domain in filamin C, its chaperone HSPA8, and PKCα in the Z-disc of skeletal muscle. Studies of Ldb3Ala165Val/+ mice indicate that the myopathy-associated LDB3 p.Ala165Val mutation triggers early aggregation of filamin C and its chaperones at muscle Z-disc before aggregation of the mutant protein. The mutation causes protein aggregation and eventually Z-disc myofibrillar disruption by impairing PKCα and TSC2-mTOR, two important signaling pathways regulating protein stability and disposal of damaged cytoskeletal components at a major mechanosensor hub in the Z-disc of skeletal muscle.

δ-Opioid receptor as a potential therapeutic target for ischemic stroke.

Ischemic stroke is a global epidemic condition due to an inadequate supply of blood and oxygen to a specific area of brain either by arterial blockage or by narrowing of blood vessels. Despite having advancement in the use of thrombolytic and clot removal medicine, significant numbers of stroke patients are still left out without option for treatment. In this review, we summarize recent research work on the activation of δ-opioid receptor as a strategy for treating ischemic stroke-caused neuronal injury. Moreover, as activation of δ-opioid receptor by a non-peptidic δ-opioid receptor agonist also modulates the expression, maturation and processing of amyloid precursor protein and ß-secretase activity, the potential role of these effects on ischemic stroke caused dementia or Alzheimer's disease are also discussed.

Attenuation of Ischemic Stroke-Caused Brain Injury by a Monoamine Oxidase Inhibitor Involves Improved Proteostasis and Reduced Neuroinflammation.

Mitochondrial dysfunction and oxidative stress play a key role in ischemia/reperfusion (I/R) induced brain injury. We previously showed that ubiquilin-1 (Ubqln1), a ubiquitin-like protein, improves proteostasis and protects brains against oxidative stress and I/R induced brain injury. We demonstrate here that nialamide (NM), a non-selective monoamine oxidase (MAO) inhibitor, upregulated Ublqn1 and protected neurons from oxygen-glucose deprivation- and I/R-caused cell death in in vitro and in vivo, respectively. Post-ischemic administration of the NM in a stroke mouse model even at 3 h following I/R still reduced neuronal injury and improved functional recovery and survival. Treating stroke animals with NM also increased the association of Ubqln1 with mitochondria and decreased the total oxidized and polyubiquitinated protein levels. Intriguingly, NM-enhanced proteostasis was also associated with reduced I/R-caused neuroinflammation, as reflected by attenuated activation of microglia and astrocytes as well as reduced TNF-α level. Thus, our results suggest that MAO inhibition-induced neuroprotection following I/R involves improved proteostasis and reduced neuroinflammation.