Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by accumulation of fragmented insoluble TDP-43 and loss of TDP-43 from the nucleus. Increased expression of exogenous ...TARDBP (encoding TDP-43) induces TDP-43 pathology and cytotoxicity, suggesting the involvement of aberrant expression of TDP-43 in the pathogenesis of ALS. In normal conditions, however, the amount of TDP-43 is tightly regulated by the autoregulatory mechanism involving alternative splicing of TARDBP mRNA. To investigate the influence of autoregulation dysfunction, we inhibited the splicing of cryptic intron 6 using antisense oligonucleotides in vivo. This inhibition doubled the Tardbp mRNA expression, increased the fragmented insoluble TDP-43, and reduced the number of motor neurons in the mouse spinal cord. In human induced pluripotent stem cell-derived neurons, the splicing inhibition of intron 6 increased TARDBP mRNA and decreased nuclear TDP-43. These non-genetically modified models exhibiting rise in the TARDBP mRNA levels suggest that TDP-43 autoregulation turbulence might be linked to the pathogenesis of ALS.
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•Decreased splicing of cryptic intron 6 disrupts TDP-43 autoregulation.•Disruption of TDP-43 autoregulation increases TARDBP mRNA by more than 2-fold.•Increase in endogenous TARDBP mRNA induces fragmented and insoluble TDP-43.•Increased TARDBP mRNA is associated with loss of nuclear TDP-43.
Theoretically, direct chemical reprogramming of somatic cells into neurons in the infarct area represents a promising regenerative therapy for ischemic stroke. Previous studies have reported that ...human fibroblasts and astrocytes transdifferentiate into neuronal cells in the presence of small molecules without introducing ectopic transgenes. However, the optimal combination of small molecules for the transdifferentiation of macrophages into neurons has not yet been determined. The authors hypothesized that a combination of small molecules could induce the transdifferentiation of monocyte-derived macrophages into neurons and that the administration of this combination may be a regenerative therapy for ischemic stroke because monocytes and macrophages are directly involved in the ischemic area. Transcriptomes and morphologies of the cells were compared before and after stimulation using RNA sequencing and immunofluorescence staining. Microscopic analyses were also performed to identify cell markers and evaluate functional recovery by blinded examination following the administration of small molecules after ischemic stroke in CB-17 mice. In this study, an essential combination of six small molecules CHIR99021, Dorsomorphin, Forskolin, isoxazole-9 (ISX-9), Y27632, and DB2313 that transdifferentiated monocyte-derived macrophages into neurons
was identified. Moreover, administration of six small molecules after cerebral ischemia in model animals generated a new neuronal layer in the infarct cortex by converting macrophages into neuronal cells, ultimately improving neurological function. These results suggest that altering the transdifferentiation of monocyte-derived macrophages by the small molecules to adjust their adaptive response will facilitate the development of regenerative therapies for ischemic stroke.
Purpose
To assess the effect of maintenance therapy on visual outcomes in preventing recurrences one year after first onset in patients with aquaporin-4 antibody (AQP4Ab)-positive optic neuritis.
...Study design
Retrospective study.
Methods
The medical charts of 56 patients with optic neuritis (22 with AQP4Ab-positive and 34 with AQP4Ab-negative) at Niigata University Medical and Dental Hospital were retrospectively analyzed. Clinical characteristics, including visual acuity and number of recurrences one year after first onset, were compared among patients who were AQP4Ab-positivie with and those without maintenance therapy such as oral prednisolone and azathioprine, as well as those who were AQP4Ab-negative.
Results
The mean ages were 49.3 and 45.2 years in the AQP4Ab-positive and the AQP4Ab-negative groups. The female to male ratio was 21:1 and 18:16 in the two groups, respectively. Multiple between-group comparison showed a statistically significant difference in visual acuity one year after first onset between the AQP4Ab-positive without maintenance therapy group and the AQP4Ab-negative group (0.05 (median, same applies below) vs. 1.0, p < 0.01). There was also a statistically significant difference in the number of recurrences in the year after first onset between the AQP4Ab-positive with and without maintenance therapy groups (1 vs. 0, p < 0.01).
Conclusion
This study demonstrates that patients with AQP4Ab-positive optic neuritis without maintenance therapy had the poorest visual acuity and the most recurrences one year after first onset. These results indicate that reducing the number of recurrences with maintenance therapy could improve the visual outcomes in patients with AQP4Ab-positive optic neuritis.
TAR DNA-binding protein 43 (TDP-43) is a causative factor of amyotrophic lateral sclerosis (ALS). Cytoplasmic TDP-43 aggregates in neurons are a hallmark pathology of ALS. Under various stress ...conditions, TDP-43 localizes sequentially to two cytoplasmic protein aggregates, namely, stress granules (SGs) first and then aggresomes. Accumulating evidence suggests that delayed clearance of TDP-43-positive SGs is associated with pathological TDP-43 aggregates in ALS. We found that ubiquitin-specific protease 10 (USP10) promotes the clearance of TDP-43-positive SGs in cells treated with proteasome inhibitor, thereby promoting the formation of TDP-43-positive aggresomes, and the depletion of USP10 increases the amount of insoluble TDP-35, a cleaved product of TDP-43, in the cytoplasm. TDP-35 interacted with USP10 in an RNA-binding-dependent manner; however, impaired RNA binding of TDP-35 reduced the localization in SGs and aggresomes and induced USP10-negative TDP-35 aggregates. Immunohistochemistry showed that most of the cytoplasmic TDP-43/TDP-35 aggregates in the neurons of ALS patients were USP10 negative. Our findings suggest that USP10 inhibits aberrant aggregation of TDP-43/TDP-35 in the cytoplasm of neuronal cells by promoting the clearance of TDP-43/TDP-35-positive SGs and facilitating the formation of TDP-43/TDP-35-positive aggresomes.
Reperfusion therapies by tissue plasminogen activator (tPA) and mechanical thrombectomy (MT) have ushered in a new era in the treatment of acute ischemic stroke (AIS). However, reperfusion ...therapy-related HT remains an enigma.
To provide a comprehensive review focused on emerging concepts of stroke and therapeutic strategies, including the use of protective agents to prevent HT after reperfusion therapies for AIS.
A literature review was performed using PubMed and the ClinicalTrials.gov database.
Risk of HT increases with delayed initiation of tPA treatment, higher baseline glucose level, age, stroke severity, episode of transient ischemic attack within 7 days of stroke onset, and hypertension. At a molecular level, HT that develops after thrombolysis is thought to be caused by reactive oxygen species, inflammation, remodeling factor-mediated effects, and tPA toxicity. Modulation of these pathophysiological mechanisms could be a therapeutic strategy to prevent HT after tPA treatment. Clinical mechanisms underlying HT after MT are thought to involve smoking, a low Alberta Stroke Program Early CT Score, use of general anesthesia, unfavorable collaterals, and thromboembolic migration. However, the molecular mechanisms are yet to be fully investigated. Clinical trials with MT and protective agents have also been planned and good outcomes are expected.
To fully utilize the easily accessible drug—tPA—and the high recanalization rate of MT, it is important to reduce bleeding complications after recanalization. A future study direction could be to investigate the recovery of neurological function by combining reperfusion therapies with cell therapies and/or use of pleiotropic protective agents.
•Reperfusion therapy-related hemorrhage remains an enigma.•We review the therapeutic strategies to prevent hemorrhage after reperfusion for AIS.•Effects of combination therapy with pleiotropic agents and tPA have been investigated.•Hemorrhagic risk in thrombectomy may be lower than that with tPA treatment alone.•Combined reperfusion therapies with cell therapies and/or pleiotropic protective agents might be useful.
Cell-therapies that invoke pleiotropic mechanisms may facilitate functional recovery in stroke patients. We hypothesized that a cell therapy using microglia preconditioned by optimal oxygen-glucose ...deprivation (OGD) is a therapeutic strategy for ischemic stroke because optimal ischemia induces anti-inflammatory M2 microglia. We first delineated changes in angiogenesis and axonal outgrowth in the ischemic cortex using rats. We found that slight angiogenesis without axonal outgrowth were activated at the border area within the ischemic core from 7 to 14 days after ischemia. Next, we demonstrated that administration of primary microglia preconditioned by 18 hours of OGD at 7 days prompted functional recovery at 28 days after focal cerebral ischemia compared to control therapies by marked secretion of remodelling factors such as vascular endothelial growth factor, matrix metalloproteinase-9, and transforming growth factor-β polarized to M2 microglia in vitro/vivo. In conclusion, intravascular administration of M2 microglia preconditioned by optimal OGD may be a novel therapeutic strategy against ischemic stroke.
Abnormal expansions of GGGGCC repeat sequence in the noncoding region of the
gene is the most common cause of familial amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). The ...expanded repeat sequence is translated into dipeptide repeat proteins (DPRs) by noncanonical repeat-associated non-AUG (RAN) translation. Since DPRs play central roles in the pathogenesis of C9-ALS/FTD, we here investigate the regulatory mechanisms of RAN translation, focusing on the effects of RNA-binding proteins (RBPs) targeting GGGGCC repeat RNAs. Using C9-ALS/FTD model flies, we demonstrated that the ALS/FTD-linked RBP FUS suppresses RAN translation and neurodegeneration in an RNA-binding activity-dependent manner. Moreover, we found that FUS directly binds to and modulates the G-quadruplex structure of GGGGCC repeat RNA as an RNA chaperone, resulting in the suppression of RAN translation in vitro. These results reveal a previously unrecognized regulatory mechanism of RAN translation by G-quadruplex-targeting RBPs, providing therapeutic insights for C9-ALS/FTD and other repeat expansion diseases.
Abstract
Background
Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by sudden onset thunderclap headache and multiple segmental reversible cerebral vasoconstrictions that ...improve within 3 months. The postpartum period is a well-known precipitating factor for the onset of RCVS. Cerebral venous thrombosis (CVT) causes thunderclap headaches in the postpartum period. While headache in CVT is sometimes exacerbated in the supine position, the severity of the headache in RCVS is usually independent of body position. In this study, we report a case of RCVS with thunderclap headache exacerbated in the supine position, and headache attacks that resolved quickly in the standing position during the postpartum period.
Case presentation
A 33-year-old woman presented with a sudden increase in blood pressure and thunderclap headache on the fifth postpartum day (day 1: the first sick day). The headache was severe and pulsatile, with onset in the supine position in bed, and peaked at approximately 10 s. It was accompanied by nausea and chills but there were no scintillating scotomas or ophthalmic symptoms. The headache resolved in the standing or sitting position but was exacerbated and became unbearable within a few seconds when the patient was in the supine position. Therefore, she was unable to lie supine at night. Computed tomography angiography (CTA) of the head on day 2 and magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) on day 3 showed no abnormalities. However, considering the possibility of RCVS, verapamil was initiated on day 3. The headache resolved the following day. MRA of the head on day 10 revealed diffuse and segmental stenoses in the bilateral middle and posterior cerebral arteries and basilar artery. Therefore, the patient was diagnosed with RCVS. The headache gradually resolved and disappeared completely on day 42. Cerebral vasoconstriction was also improved on MRA on day 43.
Conclusions
This postpartum RCVS case was notable for the exacerbation of headaches in the supine position. For the diagnosis of thunderclap headache in the postpartum period, RCVS should be considered in addition to CVT when the patient presents with a headache that is exacerbated in the supine position.
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder. Accumulating evidence has shown that 43kDa TAR‐DNA–binding protein (TDP‐43) is the disease protein in ALS and frontotemporal ...lobar degeneration. We previously reported a familial ALS with Bumina bodies and TDP‐43‐positive skein‐like inclusions in the lower motor neurons; these findings are indistinguishable from those of sporadic ALS. In three affected individuals in two generations of one family, we found a single base‐pair change from A to G at position 1028 in TDP‐43, which resulted in a Gln‐to‐Arg substitution at position 343. Our findings provide a new insight into the molecular pathogenesis of ALS. Ann Neurol 2008;63:538–542
Stroke remains a major cause of serious disability because the brain has a limited capacity to regenerate. In the last two decades, therapies for stroke have dramatically changed. However, half of ...the patients cannot achieve functional independence after treatment. Presently, cell-based therapies are being investigated to improve functional outcomes. This review aims to describe conventional cell therapies under clinical trial and outline the novel concept of polarized cell therapies based on protective cell phenotypes, which are currently in pre-clinical studies, to facilitate functional recovery after post-reperfusion treatment in patients with ischemic stroke. In particular, non-neuronal stem cells, such as bone marrow-derived mesenchymal stem/stromal cells and mononuclear cells, confer no risk of tumorigenesis and are safe because they do not induce rejection and allergy; they also pose no ethical issues. Therefore, recent studies have focused on them as a cell source for cell therapies. Some clinical trials have shown beneficial therapeutic effects of bone marrow-derived cells in this regard, whereas others have shown no such effects. Therefore, more clinical trials must be performed to reach a conclusion. Polarized microglia or peripheral blood mononuclear cells might provide promising therapeutic strategies after stroke because they have pleiotropic effects. In traumatic injuries and neurodegenerative diseases, astrocytes, neutrophils, and T cells were polarized to the protective phenotype in pre-clinical studies. As such, they might be useful therapeutic targets. Polarized cell therapies are gaining attention in the treatment of stroke and neurological diseases.
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