Evaluating protein cross-linking as a therapeutic strategy to stabilize SOD1 variants in a mouse model of familial ALS.

Mutations in the gene encoding Cu-Zn superoxide dismutase 1 (SOD1) cause a subset of familial amyotrophic lateral sclerosis (fALS) cases. A shared effect of these mutations is that SOD1, which is normally a stable dimer, dissociates into toxic monomers that seed toxic aggregates. Considerable research effort has been devoted to developing compounds that stabilize the dimer of fALS SOD1 variants, but unfortunately, this has not yet resulted in a treatment. We hypothesized that cyclic thiosulfinate cross-linkers, which selectively target a rare, 2 cysteine-containing motif, can stabilize fALS-causing SOD1 variants in vivo. We created a library of chemically diverse cyclic thiosulfinates and determined structure-cross-linking-activity relationships. A pre-lead compound, "S-XL6," was selected based upon its cross-linking rate and drug-like properties. Co-crystallographic structure clearly establishes the binding of S-XL6 at Cys 111 bridging the monomers and stabilizing the SOD1 dimer. Biophysical studies reveal that the degree of stabilization afforded by S-XL6 (up to 24°C) is unprecedented for fALS, and to our knowledge, for any protein target of any kinetic stabilizer. Gene silencing and protein degrading therapeutic approaches require careful dose titration to balance the benefit of diminished fALS SOD1 expression with the toxic loss-of-enzymatic function. We show that S-XL6 does not share this liability because it rescues the activity of fALS SOD1 variants. No pharmacological agent has been proven to bind to SOD1 in vivo. Here, using a fALS mouse model, we demonstrate oral bioavailability; rapid engagement of SOD1G93A by S-XL6 that increases SOD1G93A's in vivo half-life; and that S-XL6 crosses the blood-brain barrier. S-XL6 demonstrated a degree of selectivity by avoiding off-target binding to plasma proteins. Taken together, our results indicate that cyclic thiosulfinate-mediated SOD1 stabilization should receive further attention as a potential therapeutic approach for fALS.

Quantifying and Mitigating Motor Phenotypes Induced by Antisense Oligonucleotides in the Central Nervous System.

Antisense oligonucleotides (ASOs) are emerging as a promising class of therapeutics for neurological diseases. When injected directly into cerebrospinal fluid, ASOs distribute broadly across brain regions and exert long-lasting therapeutic effects. However, many phosphorothioate (PS)-modified gapmer ASOs show transient motor phenotypes when injected into the cerebrospinal fluid, ranging from reduced motor activity to ataxia or acute seizure-like phenotypes. Using a behavioral scoring assay customized to reflect the timing and nature of these effects, we show that both sugar and phosphate modifications influence acute motor phenotypes. Among sugar analogues, DNA induces the strongest motor phenotypes while 2'-substituted RNA modifications improve the tolerability of PS-ASOs. Reducing the PS content of gapmer ASOs, which contain a stretch of PS-DNA, improves their toxicity profile, but in some cases also reduces efficacy or duration of effect. We show that this acute toxicity is not mediated by major nucleic acid sensing immune pathways. Formulating ASOs with divalent ions before injection and avoiding phosphate-based buffers modestly improved tolerability through mechanisms at least partially distinct from reduced PS content. Overall, our work identifies and quantifies an understudied aspect of oligonucleotide toxicology in the CNS, explores its mechanism, and presents platform-level medicinal chemistry and formulation approaches that improve tolerability of this class of compounds.

Artificial microRNA suppresses C9ORF72 variants and decreases toxic dipeptide repeat proteins in vivo.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects motor neurons, causing progressive muscle weakness and respiratory failure. The presence of an expanded hexanucleotide repeat in chromosome 9 open reading frame 72 (C9ORF72) is the most frequent mutation causing familial ALS and frontotemporal dementia (FTD). To determine if suppressing expression of C9ORF72 gene products can reduce toxicity, we designed a set of artificial microRNAs (amiRNA) targeting the human C9ORF72 gene. Here we report that an AAV9-mediated amiRNA significantly suppresses expression of the C9ORF72 mRNA, protein, and toxic dipeptide repeat proteins generated by the expanded repeat in the brain and spinal cord of C9ORF72 transgenic mice.

Incidence, Prevalence, and Racial and Ethnic Distribution of Inflammatory Bowel Disease in the United States.

BACKGROUND & AIMS: We sought to estimate the incidence, prevalence, and racial-ethnic distribution of physician-diagnosed inflammatory bowel disease (IBD) in the United States. METHODS: The study used 4 administrative claims data sets: a 20% random sample of national fee-for-service Medicare data (2007 to 2017); Medicaid data from Florida, New York, Pennsylvania, Ohio, and California (1999 to 2012); and commercial health insurance data from Anthem beneficiaries (2006 to 2018) and Optum's deidentified Clinformatics Data Mart (2000 to 2017). We used validated combinations of medical diagnoses, diagnostic procedures, and prescription medications to identify incident and prevalent diagnoses. We computed pooled age-, sex-, and race/ethnicity-specific insurance-weighted estimates and pooled estimates standardized to 2018 United States Census estimates with 95% confidence intervals (CIs). RESULTS: The age- and sex-standardized incidence of IBD per 100,000 person-years was 10.9 (95% CI, 10.6-11.2). The incidence of IBD peaked in the third decade of life, decreased to a relatively stable level across the fourth to eighth decades, and declined further. The age-, sex- and insurance-standardized prevalence of IBD was 721 per 100,000 population (95% CI, 717-726). Extrapolated to the 2020 United States Census, an estimated 2.39 million Americans are diagnosed with IBD. The prevalence of IBD per 100,000 population was 812 (95% CI, 802-823) in White, 504 (95% CI, 482-526) in Black, 403 (95% CI, 373-433) in Asian, and 458 (95% CI, 440-476) in Hispanic Americans. CONCLUSIONS: IBD is diagnosed in >0.7% of Americans. The incidence peaks in early adulthood and then plateaus at a lower rate. The disease is less commonly diagnosed in Black, Asian, and Hispanic Americans.

Finale: impact of the ORCHESTRA/ENCORE programmes on Southern Ocean heat and carbon understanding.

The 5-year Ocean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA) programme and its 1-year extension ENCORE (ENCORE is the National Capability ORCHESTRA Extension) was an approximately 11-million-pound programme involving seven UK research centres that finished in March 2022. The project sought to radically improve our ability to measure, understand and predict the exchange, storage and export of heat and carbon by the Southern Ocean. It achieved this through a series of milestone observational campaigns in combination with model development and analysis. Twelve cruises in the Weddell Sea and South Atlantic were undertaken, along with mooring, glider and profiler deployments and aircraft missions, all contributing to measurements of internal ocean and air-sea heat and carbon fluxes. Numerous forward and adjoint numerical experiments were developed and supported by the analysis of coupled climate models. The programme has resulted in over 100 peer-reviewed publications to date as well as significant impacts on climate assessments and policy and science coordination groups. Here, we summarize the research highlights of the programme and assess the progress achieved by ORCHESTRA/ENCORE and the questions it raises for the future. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.

Genetic diversity of axon degenerative mechanisms in models of Parkinson's disease.

Parkinson's disease (PD) is the most common form of neurodegenerative movement disorder, associated with profound loss of dopaminergic neurons from the basal ganglia. Though loss of dopaminergic neuron cell bodies from the substantia nigra pars compacta is a well-studied feature, atrophy and loss of their axons within the nigrostriatal tract is also emerging as an early event in disease progression. Genes that drive the Wallerian degeneration, like Sterile alpha and toll/interleukin-1 receptor motif containing (Sarm1), are excellent candidates for driving this axon degeneration, given similarities in the morphology of axon degeneration after axotomy and in PD. In the present study we assessed whether Sarm1 contributes to loss of dopaminergic projections in mouse models of PD. In Sarm1 deficient mice, we observed a significant delay in the degeneration of severed dopaminergic axons distal to a 6-OHDA lesion of the medial forebrain bundle (MFB) in the nigrostriatal tract, and an accompanying rescue of morphological, biochemical and behavioural phenotypes. However, we observed no difference compared to controls when striatal terminals were lesioned with 6-OHDA to induce a dying back form of neurodegeneration. Likewise, when PD phenotypes were induced using AAV-induced alpha-synuclein overexpression, we observed similar modest loss of dopaminergic terminals in Sarm1 knockouts and controls. Our data argues that axon degeneration after MFB lesion is Sarm1-dependent, but that other models for PD do not require Sarm1, or that Sarm1 acts with other redundant genetic pathways. This work adds to a growing body of evidence indicating Sarm1 contributes to some, but not all types of neurodegeneration, and supports the notion that while axon degeneration in many context appears morphologically similar, a diversity of axon degeneration programs exist.

Loss of Sarm1 does not suppress motor neuron degeneration in the SOD1G93A mouse model of amyotrophic lateral sclerosis.

Axon degeneration occurs in all neurodegenerative diseases, but the molecular pathways regulating axon destruction during neurodegeneration are poorly understood. Sterile Alpha and TIR Motif Containing 1 (Sarm1) is an essential component of the prodegenerative pathway driving axon degeneration after axotomy and represents an appealing target for therapeutic intervention in neurological conditions involving axon loss. Amyotrophic lateral sclerosis (ALS) is characterized by rapid, progressive motor neuron degeneration and muscle atrophy, causing paralysis and death. Patient tissue and animal models of ALS show destruction of upper and lower motor neuron cell bodies and loss of their associated axons. Here, we investigate whether loss of Sarm1 can mitigate motor neuron degeneration in the SOD1G93A mouse model of ALS. We found no change in survival, behavioral, electrophysiogical or histopathological outcomes in SOD1G93A mice null for Sarm1. Blocking Sarm1-mediated axon destruction alone is therefore not sufficient to suppress SOD1G93A-induced neurodegeneration. Our data suggest the molecular pathways driving axon loss in ALS may be Sarm1-independent or involve genetic pathways that act in a redundant fashion with Sarm1.

Meta-analysis of the Therapeutic Impact of Cannabinoids in Inflammatory Bowel Disease.

BACKGROUND: With the increasing legalization of medical and recreational cannabis, patients and providers have growing interest in the role of cannabinoids in treating inflammatory bowel disease. Prior meta-analysis has shown inconclusive evidence for efficacy of cannabinoids. We sought to produce an up-to-date meta-analysis that pools new data to evaluate the therapeutic effects of cannabinoids in both Crohn's disease (CD) and ulcerative colitis (UC). METHODS: PubMed, Embase, CENTRAL and CINAHL were queried for randomized-controlled trials evaluating the impact cannabinoids in CD or UC. Random effects modeling was used to compute pooled estimates of risk difference. Heterogeneity was assessed using I2. RESULTS: Eight studies, including 4 studies of CD, 3 studies of UC, and 1 study of both diseases met inclusion criteria. Among 5 studies of CD, a statistically significant decrease in clinical disease activity following intervention was observed (risk ratios [RR],  -0.91; 95% CI, CI:1.54 to CI:0.28, I2 = 71.9%). Clinical disease activity in UC was not significantly lower in the pooled analysis (RR, -2.13; 95% CI, -4.80 to 0.55; I2 = 90.3%). Improvement in quality of life (QoL) was observed in both CD and UC combined (RR, 1.79; 95% CI, 0.92-0.2.66; I2 = 82.8%), as well as individually. No differences were observed in the analysis on endoscopic disease activity and inflammatory markers. CONCLUSIONS: This meta-analysis of clinical trials suggests that cannabinoids are associated with improved quality of life in both CD and UC, as well as improved disease activity but not inflammation.

This updated systematic review and meta-analysis suggests that cannabis for inflammatory bowel disease may improve quality of life and disease activity but not inflammation.

Identification of selective and non-selective C9ORF72 targeting in vivo active siRNAs.

A hexanucleotide (G4C2) repeat expansion (HRE) within intron one of C9ORF72 is the leading genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). C9ORF72 haploinsufficiency, formation of RNA foci, and production of dipeptide repeat (DPR) proteins have been proposed as mechanisms of disease. Here, we report the first example of disease-modifying siRNAs for C9ORF72 driven ALS/FTD. Using a combination of reporter assay and primary cortical neurons derived from a C9-ALS/FTD mouse model, we screened a panel of more than 150 fully chemically stabilized siRNAs targeting different C9ORF72 transcriptional variants. We demonstrate the lack of correlation between siRNA efficacy in reporter assay versus native environment; repeat-containing C9ORF72 mRNA variants are found to preferentially localize to the nucleus, and thus C9ORF72 mRNA accessibility and intracellular localization have a dominant impact on functional RNAi. Using a C9-ALS/FTD mouse model, we demonstrate that divalent siRNAs targeting C9ORF72 mRNA variants specifically or non-selectively reduce the expression of C9ORF72 mRNA and significantly reduce DPR proteins. Interestingly, siRNA silencing all C9ORF72 mRNA transcripts was more effective in removing intranuclear mRNA aggregates than targeting only HRE-containing C9ORF72 mRNA transcripts. Combined, these data support RNAi-based degradation of C9ORF72 as a potential therapeutic paradigm.

RNAi-mediated silencing of SOD1 profoundly extends survival and functional outcomes in ALS mice.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative condition, with 20% of familial and 2-3% of sporadic cases linked to mutations in the cytosolic superoxide dismutase (SOD1) gene. Mutant SOD1 protein is toxic to motor neurons, making SOD1 gene lowering a promising approach, supported by preclinical data and the 2023 FDA approval of the GapmeR ASO targeting SOD1, tofersen. Despite the approval of an ASO and the optimism it brings to the field, the pharmacodynamics and pharmacokinetics of therapeutic SOD1 modulation can be improved. Here, we developed a chemically stabilized divalent siRNA scaffold (di-siRNA) that effectively suppresses SOD1 expression in vitro and in vivo. With optimized chemical modification, it achieves remarkable CNS tissue permeation and SOD1 silencing in vivo. Administered intraventricularly, di-siRNASOD1 extended survival in SOD1-G93A ALS mice, surpassing survival previously seen in these mice by ASO modalities, slowed disease progression, and prevented ALS neuropathology. These properties offer an improved therapeutic strategy for SOD1-mediated ALS and may extend to other dominantly inherited neurological disorders.

Mutant SOD1-expressing astrocytes release toxic factors that trigger motoneuron death by inducing hyperexcitability.

Amyotrophic lateral sclerosis (ALS) is a devastating paralytic disorder caused by dysfunction and degeneration of motoneurons starting in adulthood. Recent studies using cell or animal models document that astrocytes expressing disease-causing mutations of human superoxide dismutase 1 (hSOD1) contribute to the pathogenesis of ALS by releasing a neurotoxic factor(s). Neither the mechanism by which this neurotoxic factor induces motoneuron death nor its cellular site of action has been elucidated. Here we show that acute exposure of primary wild-type spinal cord cultures to conditioned medium derived from astrocytes expressing mutant SOD1 (ACM-hSOD1(G93A)) increases persistent sodium inward currents (PC(Na)), repetitive firing, and intracellular calcium transients, leading to specific motoneuron death days later. In contrast to TTX, which paradoxically increased twofold the amplitude of calcium transients and killed motoneurons, reduction of hyperexcitability by other specific (mexiletine) and nonspecific (spermidine and riluzole) blockers of voltage-sensitive sodium (Na(v)) channels restored basal calcium transients and prevented motoneuron death induced by ACM-hSOD1(G93A). These findings suggest that riluzole, the only FDA-approved drug with known benefits for ALS patients, acts by inhibiting hyperexcitability. Together, our data document that a critical element mediating the non-cell-autonomous toxicity of ACM-hSOD1(G93A) on motoneurons is increased excitability, an observation with direct implications for therapy of ALS.

Loss of TDP-43 function contributes to genomic instability in amyotrophic lateral sclerosis.

A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the cytoplasmic mislocalization and aggregation of the DNA/RNA-binding protein TDP-43, but how loss of nuclear TDP-43 function contributes to ALS and FTD pathogenesis remains largely unknown. Here, using large-scale RNAi screening, we identify TARDBP, which encodes TDP-43, as a gene whose loss-of-function results in elevated DNA mutation rate and genomic instability. Consistent with this finding, we observe increased DNA damage in induced pluripotent stem cells (iPSCs) and iPSC-derived post-mitotic neurons generated from ALS patients harboring TARDBP mutations. We find that the increase in DNA damage in ALS iPSC-derived neurons is due to defects in two major pathways for DNA double-strand break repair: non-homologous end joining and homologous recombination. Cells with defects in DNA repair are sensitive to DNA damaging agents and, accordingly, we find that ALS iPSC-derived neurons show a marked reduction in survival following treatment with a DNA damaging agent. Importantly, we find that increased DNA damage is also observed in neurons with nuclear TDP-43 depletion from ALS/FTD patient brain tissues. Collectively, our results demonstrate that ALS neurons with loss of nuclear TDP-43 function have elevated levels of DNA damage and contribute to the idea that genomic instability is a defining pathological feature of ALS/FTD patients with TDP-43 pathology.

Development and Validation of Claims-Based Definitions to Identify Incident and Prevalent Inflammatory Bowel Disease in Administrative Healthcare Databases.

BACKGROUND: To facilitate inflammatory bowel disease (IBD) research in the United States, we developed and validated claims-based definitions to identify incident and prevalent IBD diagnoses using administrative healthcare claims data among multiple payers. METHODS: We used data from Medicare, Medicaid, and the HealthCore Integrated Research Database (Anthem commercial and Medicare Advantage claims). The gold standard for validation was review of medical records. We evaluated 1 incidence and 4 prevalence algorithms based on a combination of International Classification of Diseases codes, National Drug Codes, and Current Procedural Terminology codes. The claims-based incident diagnosis date needed to be within ±90 days of that recorded in the medical record to be valid. RESULTS: We reviewed 111 charts of patients with a potentially incident diagnosis. The positive predictive value (PPV) of the claims algorithm was 91% (95% confidence interval [CI], 81%-97%). We reviewed 332 charts to validate prevalent case definition algorithms. The PPV was 94% (95% CI, 86%-98%) for ≥2 IBD diagnoses and presence of prescriptions for IBD medications, 92% (95% CI, 85%-97%) for ≥2 diagnoses without any medications, 78% (95% CI, 67%-87%) for a single diagnosis and presence of an IBD medication, and 35% (95% CI, 25%-46%) for 1 physician diagnosis and no IBD medications. CONCLUSIONS: Through a combination of diagnosis, procedural, and medication codes in insurance claims data, we were able to identify incident and prevalent IBD cases with high accuracy. These algorithms can be useful for the ascertainment of IBD cases in future studies.

Up-regulation of cholesterol synthesis pathways and limited neurodegeneration in a knock-in Sod1 mutant mouse model of ALS.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder affecting brain and spinal cord motor neurons. Mutations in the copper/zinc superoxide dismutase gene ( SOD1 ) are associated with ∼20% of inherited and 1-2% of sporadic ALS cases. Much has been learned from mice expressing transgenic copies of mutant SOD1, which typically involve high-level transgene expression, thereby differing from ALS patients expressing one mutant gene copy. To generate a model that more closely represents patient gene expression, we created a knock-in point mutation (G85R, a human ALS-causing mutation) in the endogenous mouse Sod1 gene, leading to mutant SOD1 G85R protein expression. Heterozygous Sod1 G85R mutant mice resemble wild type, whereas homozygous mutants have reduced body weight and lifespan, a mild neurodegenerative phenotype, and express very low mutant SOD1 protein levels with no detectable SOD1 activity. Homozygous mutants exhibit partial neuromuscular junction denervation at 3-4 months of age. Spinal cord motor neuron transcriptome analyses of homozygous Sod1 G85R mice revealed up-regulation of cholesterol synthesis pathway genes compared to wild type. Transcriptome and phenotypic features of these mice are similar to Sod1 knock-out mice, suggesting the Sod1 G85R phenotype is largely driven by loss of SOD1 function. By contrast, cholesterol synthesis genes are down-regulated in severely affected human TgSOD1 G93A transgenic mice at 4 months. Our analyses implicate dysregulation of cholesterol or related lipid pathway genes in ALS pathogenesis. The Sod1 G85R knock-in mouse is a useful ALS model to examine the importance of SOD1 activity in control of cholesterol homeostasis and motor neuron survival. SIGNIFICANCE STATEMENT: Amyotrophic lateral sclerosis is a devastating disease involving the progressive loss of motor neurons and motor function for which there is currently no cure. Understanding biological mechanisms leading to motor neuron death is critical for developing new treatments. Using a new knock-in mutant mouse model carrying a Sod1 mutation that causes ALS in patients, and in the mouse, causes a limited neurodegenerative phenotype similar to Sod1 loss-of-function, we show that cholesterol synthesis pathway genes are up-regulated in mutant motor neurons, whereas the same genes are down-regulated in transgenic SOD1 mice with a severe phenotype. Our data implicate dysregulation of cholesterol or other related lipid genes in ALS pathogenesis and provide new insights that could contribute to strategies for disease intervention.

Efficacy of Vedolizumab in a Nationwide Cohort of Elderly Inflammatory Bowel Disease Patients.

BACKGROUND: The elderly inflammatory bowel disease (IBD) population has historically been under-represented in clinical trials, and data on the efficacy of biologic medications in elderly IBD patients are generally lacking. Our study aims to evaluate the efficacy of vedolizumab (VDZ) among elderly IBD patients and compare it with younger IBD patients in a nationwide population-based cohort of IBD patients. METHODS: We conducted a retrospective cohort study of patients within the US national Veterans Affairs Healthcare System (VAHS). Patients were stratified into 2 groups based on age at the time of starting VDZ (60 years of age and older or younger than 60 years of age) with outcomes compared between the 2 groups. The primary outcome was steroid-free remission during the 6- to 12-month period after starting VDZ therapy among those patients who were on steroids when VDZ was started. RESULTS: There were 568 patients treated with VDZ, of whom 56.7% had Crohn's disease and 43.3% had ulcerative colitis. Among them, 316 patients were on steroids when VDZ was started. The percentage of patients who were on VDZ and off steroids during the 6- to 12-month period after VDZ initiation was 46.8% and 40.1% for the younger and elderly groups, respectively (P = 0.2374). Rates of hospitalization for an IBD-related reason within 1 year of VDZ start among the whole cohort were nearly identical in the younger and elderly groups (11.2% vs 11.3%, P = 0.9737). Rates of surgery for an IBD-related reason within 1 year of VDZ start were also similar between the young and elderly (3.9% vs 3.9%, P = 0.9851). CONCLUSIONS: In a nationwide real-world retrospective cohort study of elderly IBD patients, we found that the efficacy of VDZ was similar among younger and older IBD patients and comparable with the published data in clinical trials.

Suppression of mutant C9orf72 expression by a potent mixed backbone antisense oligonucleotide.

Expansions of a G4C2 repeat in the C9ORF72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two devastating adult-onset neurodegenerative disorders. Using C9-ALS/FTD patient-derived cells and C9ORF72 BAC transgenic mice, we generated and optimized antisense oligonucleotides (ASOs) that selectively blunt expression of G4C2 repeat-containing transcripts and effectively suppress tissue levels of poly(GP) dipeptides. ASOs with reduced phosphorothioate content showed improved tolerability without sacrificing efficacy. In a single patient harboring mutant C9ORF72 with the G4C2 repeat expansion, repeated dosing by intrathecal delivery of the optimal ASO was well tolerated, leading to significant reductions in levels of cerebrospinal fluid poly(GP). This report provides insight into the effect of nucleic acid chemistry on toxicity and, to our knowledge, for the first time demonstrates the feasibility of clinical suppression of the C9ORF72 gene. Additional clinical trials will be required to demonstrate safety and efficacy of this therapy in patients with C9ORF72 gene mutations.

Excessive release of inorganic polyphosphate by ALS/FTD astrocytes causes non-cell-autonomous toxicity to motoneurons.

Non-cell-autonomous mechanisms contribute to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), in which astrocytes release unidentified factors that are toxic to motoneurons (MNs). We report here that mouse and patient iPSC-derived astrocytes with diverse ALS/FTD-linked mutations (SOD1, TARDBP, and C9ORF72) display elevated levels of intracellular inorganic polyphosphate (polyP), a ubiquitous, negatively charged biopolymer. PolyP levels are also increased in astrocyte-conditioned media (ACM) from ALS/FTD astrocytes. ACM-mediated MN death is prevented by degrading or neutralizing polyP in ALS/FTD astrocytes or ACM. Studies further reveal that postmortem familial and sporadic ALS spinal cord sections display enriched polyP staining signals and that ALS cerebrospinal fluid (CSF) exhibits increased polyP concentrations. Our in vitro results establish excessive astrocyte-derived polyP as a critical factor in non-cell-autonomous MN degeneration and a potential therapeutic target for ALS/FTD. The CSF data indicate that polyP might serve as a new biomarker for ALS/FTD.

Estrogen attenuates left ventricular and cardiomyocyte hypertrophy by an estrogen receptor-dependent pathway that increases calcineurin degradation.

Left ventricular (LV) hypertrophy commonly develops in response to chronic hypertension and is a significant risk factor for heart failure and death. The serine-threonine phosphatase calcineurin (Cn)A plays a critical role in the development of pathological hypertrophy. Previous experimental studies in murine models show that estrogen limits pressure overload-induced hypertrophy; our purpose was to explore further the mechanisms underlying this estrogen effect. Wild-type, ovariectomized female mice were treated with placebo or 17beta-estradiol (E2), followed by transverse aortic constriction (TAC), to induce pressure overload. At 2 weeks, mice underwent physiological evaluation, immediate tissue harvest, or dispersion of cardiomyocytes. E2 replacement limited TAC-induced LV and cardiomyocyte hypertrophy while attenuating deterioration in LV systolic function and contractility. These E2 effects were associated with reduced abundance of CnA. The primary downstream targets of CnA are the nuclear factor of activated T-cell (NFAT) family of transcription factors. In transgenic mice expressing a NFAT-activated promoter/luciferase reporter gene, E2 limited TAC-induced activation of NFAT. Moreover, the inhibitory effects of E2 on LV hypertrophy were absent in CnA knockout mice, supporting the notion that CnA is an important target of E2-mediated inhibition. In cultured rat cardiac myocytes, E2 inhibited agonist-induced hypertrophy while also decreasing CnA abundance and NFAT activation. Agonist stimulation also reduced CnA ubiquitination and degradation that was prevented by E2; all in vitro effects of estrogen were reversed by an estrogen receptor (ER) antagonist. These data support that E2 reduces pressure overload induced hypertrophy by an ER-dependent mechanism that increases CnA degradation, unveiling a novel mechanism by which E2 and ERs regulate pathological LV and cardiomyocyte growth.