Premature delivery in the domestic sow in response to in utero delivery of AAV9 to fetal piglets.

Numerous pediatric neurogenetic diseases may be optimally treated by in utero gene therapy (IUGT); but advancing such treatments requires animal models that recapitulate developmental physiology relevant to humans. One disease that could benefit from IUGT is the autosomal recessive motor neuron disease spinal muscular atrophy (SMA). Current SMA gene-targeting therapeutics are more efficacious when delivered shortly after birth, however postnatal treatment is rarely curative in severely affected patients. IUGT may provide benefit for SMA patients. In previous studies, we developed a large animal porcine model of SMA using AAV9 to deliver a short hairpin RNA (shRNA) directed at porcine survival motor neuron gene (Smn) mRNA on postnatal day 5. Here, we aimed to model developmental features of SMA in fetal piglets and to demonstrate the feasibility of prenatal gene therapy by delivering AAV9-shSmn in utero. Saline (sham), AAV9-GFP, or AAV9-shSmn was injected under direct ultrasound guidance between gestational ages 77-110 days. We developed an ultrasound-guided technique to deliver virus under direct visualization to mimic the clinic setting. Saline injection was tolerated and resulted in viable, healthy piglets. Litter rejection occurred within seven days of AAV9 injection for all other rounds. Our real-world experience of in utero viral delivery followed by AAV9-related fetal rejection suggests that the domestic sow may not be a viable model system for preclinical in utero AAV9 gene therapy studies.

Tryptophan Metabolites Are Associated With Symptoms and Nigral Pathology in Parkinson's Disease.

BACKGROUND: The objective of this study was to determine whether neurotoxic kynurenine metabolites, induced by inflammation, in plasma and cerebrospinal fluid (CSF) are associated with symptom severity and nigral pathology in Parkinson's disease (PD). METHODS: Clinical and MRI data were obtained from 97 PD and 89 controls. We used ultra-performance liquid chromatography to quantify kynurenine metabolites and high-sensitivity multiplex assays to quantify inflammation in plasma and CSF. We evaluated group-wise differences as well as associations between the biomarkers, motor and nonmotor symptoms, and nigral R2* (MRI metric reflecting iron content). RESULTS: PD subjects had >100% higher 3-hydroxykynurenine and 14% lower 3-hydroxyanthranilic acid in plasma. The 3-HK in plasma was closely associated with both symptom severity and disease duration. PD subjects also had 23% lower kynurenic acid in the CSF. Higher CSF levels of the excitotoxin quinolinic acid were associated with more severe symptoms, whereas lower levels of the neuroprotective kynurenic acid were linked to olfactory deficits. An elevated quinolinic acid/picolinic acid ratio in the CSF correlated with higher R2* values in the substantia nigra in the entire cohort. Plasma C-reactive protein and serum amyloid alpha were associated with signs of increased kynurenine pathway activity in the CSF of PD patients, but not in controls. CONCLUSIONS: In PD, the kynurenine pathway metabolite levels are altered in both the periphery and the central nervous system, and these changes are associated with symptom severity. Replication studies are warranted in other cohorts, and these can also explore if kynurenine metabolites might be PD biomarkers and/or are involved in PD pathogenesis. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Inflammation and kynurenine pathway dysregulation in post-partum women with severe and suicidal depression.

Depression during pregnancy and the post-partum is common, with severe cases resulting in suicidal behavior. Despite the urgent and unmet medical need, the biological underpinnings of peri-partum depression remain unclear. It has been suggested that it is triggered by dynamic changes of the immune system during pregnancy and at delivery. Therefore, we investigated whether a pro-inflammatory status in plasma, together with changes in the kynurenine pathway activity, is associated with the development of severe depression and suicidal behavior in the post-partum. Our cross-sectional study targets a unique, understudied population in which the pronounced severity of symptoms required hospitalization. We analyzed plasma IL-1ß, IL-2, IL-6, IL-8, TNF-α, tryptophan, serotonin, kynurenine, nicotinamide, quinolinic- and kynurenic acids in post-partum women diagnosed with peripartum onset depression (PPD) and healthy controls (n = 165). We assessed depression severity using the Edinburgh Postnatal Depression Scale and suicidality using the Columbia-Suicide Severity Rating Scale. We found that increased plasma IL-6 and IL-8 and reductions of serotonin, IL-2 and quinolinic acid were associated with the severity of depressive symptoms and increased the risk for PPD. Moreover, women with lower serotonin levels were at an increased risk for suicidal behavior, even when adjusting for depression severity, psychosocial factors, age BMI, and medication. Our results indicate that severe depression in the post-partum involves dysregulation of the immune response and the kynurenine pathway, with a concomitant reduction in serotonin levels. We propose that inflammatory cytokines and the kynurenine pathway are potential treatment targets in PPD, opening up the possibility of novel therapeutic strategies targeting the peripartum.

Role of the kynurenine pathway and the endocannabinoid system as modulators of inflammation and personality traits.

BACKGROUND: Kynurenine pathway metabolites and endocannabinoids both exert potent regulatory effects on the immune system, but the relationship between these molecules is unknown. The role of these immunobiological mediators in emotionality and personality traits is not previously characterized. METHODS: Interleukin-6 (IL-6), 2-arachidonoylglycerol (2-AG) and picolinic acid (PIC) were measured in the plasma of physically healthy individuals who had history of mood, anxiety, and personality disorders (n = 96) or who had no history of any psychiatric disorder (n = 56) by DSM-5 Criteria. Dimensional assessments of personality were performed using the Eysenck Personality Questionnaire (EPQ) and the Tridimensional Personality Questionnaire (TPQ). RESULTS: Plasma IL-6 levels were significantly associated with plasma 2-AG levels and plasma PIC levels across all subjects. PIC levels were also negatively associated with 2-AG levels across all subjects, independent of IL-6 levels. In our analysis of the biological determinants of personality factors, we identified significant associations between IL-6 and novelty seeking assessment, and between PIC and neuroticism assessment. CONCLUSIONS: These data provide evidence of a biological link between metabolites of the kynurenine pathway, the endocannabinoid system and IL-6 and suggest that these factors may influence personality traits.

Altered Tryptophan Catabolism in Placentas From Women With Pre-eclampsia.

BACKGROUND: The kynurenine pathway enzymes, breaking down tryptophan, are abundant in placental tissue. These metabolites are involved in immunoregulatory mechanisms, although the role of this pathway in pre-eclampsia (PE) has only begun to be characterized. Here, we determined tryptophan and metabolite levels together with the expression of kynurenine pathway enzymes and inflammatory factors in placental tissue from women with and without PE. METHODS: Thirty-six placentas (18 PE and 18 controls) were analyzed for expression of kynurenine pathway enzymes indoleamine-2,3-dioxygenase (IDO1 and 2), tryptophan-2,3-dioxygenase (TDO), kynurenine-3-mono-oxygenase (KMO) and quinolinate phosphoribosyltransferase (QPRT) as well as interleukin (IL)-1ß, IL-6, and serum amyloid A (SAA). Tryptophan and kynurenine content were measured using high-pressure liquid chromatography and quinolinic acid was measured using gas chromatography-mass spectrometry. CONCLUSIONS: Tryptophan content was reduced in placentas from women with PE. There was an increased kynurenine/tryptophan ratio in placentas from women with PE but no significant change in downstream metabolites. We confirmed a reduction in IDO1 expression and found a compensatory increase in TDO expression in placentas from women with PE. SAA was reduced in PE placentas compared with controls. Our data show that tryptophan content and the inflammatory mediator SAA are both compromised in placentas from women with PE. Further studies on the role of tryptophan catabolism and mediators of inflammation in sustaining healthy immunobiological pathways in the placenta are warranted.

An inflammatory profile linked to increased suicide risk.

BACKGROUND: Suicide risk assessments are often challenging for clinicians, and therefore, biological markers are warranted as guiding tools in these assessments. Suicidal patients display increased cytokine levels in peripheral blood, although the composite inflammatory profile in the subjects is still unknown. It is also not yet established whether certain inflammatory changes are specific to suicidal subjects. To address this, we measured 45 immunobiological factors in peripheral blood and identified the biological profiles associated with cross-diagnostic suicide risk and depression, respectively. METHODS: Sixty-six women with mood and anxiety disorders underwent computerized adaptive testing for mental health, assessing depression and suicide risk. Weighted correlation network analysis was used to uncover system level associations between suicide risk, depression, and the immunobiological factors in plasma. Secondary regression models were used to establish the sensitivity of the results to potential confounders, including age, body mass index (BMI), treatment and symptoms of depression and anxiety. RESULTS: The biological profile of patients assessed to be at increased suicide risk differed from that associated with depression. At the system level, a biological cluster containing increased levels of interleukin-6, lymphocytes, monocytes, white blood cell count and polymorphonuclear leukocyte count significantly impacted suicide risk, with the latter two inferring the strongest influence. The cytokine interleukin-8 was independently and negatively associated with increased suicide risk. The results remained after adjusting for confounders. LIMITATIONS: This study is cross-sectional and not designed to prove causality. DISCUSSION: A unique immunobiological profile was linked to increased suicide risk. The profile was different from that observed in patients with depressive symptoms, and indicates that granulocyte mediated biological mechanisms could be activated in patients at risk for suicide.

Muscle contractility dysfunction precedes loss of motor unit connectivity in SOD1(G93A) mice.

INTRODUCTION: Electrophysiological measurements are used in longitudinal clinical studies to provide insight into the progression of amyotrophic lateral sclerosis (ALS) and the relationship between muscle weakness and motor unit (MU) degeneration. Here, we used a similar longitudinal approach in the Cu/Zn superoxide dismutase (SOD1[G93A]) mouse model of ALS. METHODS: In vivo muscle contractility and MU connectivity assays were assessed longitudinally in SOD1(G93A) and wild type mice from postnatal days 35 to 119. RESULTS: In SOD1(G93A) males, muscle contractility was reduced by day 35 and preceded MU loss. Muscle contractility and motor unit reduction were delayed in SOD1(G93A) females compared with males, but, just as with males, muscle contractility reduction preceded MU loss. DISCUSSION: The longitudinal contractility and connectivity paradigm employed here provides additional insight into the SOD1(G93A) mouse model and suggests that loss of muscle contractility is an early finding that may precede loss of MUs and motor neuron death. Muscle Nerve 59:254-262, 2019.

HSPB1 mutations causing hereditary neuropathy in humans disrupt non-cell autonomous protection of motor neurons.

Heat shock protein beta-1 (HSPB1), is a ubiquitously expressed, multifunctional protein chaperone. Mutations in HSPB1 result in the development of a late-onset, distal hereditary motor neuropathy type II (dHMN) and axonal Charcot-Marie Tooth disease with sensory involvement (CMT2F). The functional consequences of HSPB1 mutations associated with hereditary neuropathy are unknown. HSPB1 also displays neuroprotective properties in many neuronal disease models, including the motor neuron disease amyotrophic lateral sclerosis (ALS). HSPB1 is upregulated in SOD1-ALS animal models during disease progression, predominately in glial cells. Glial cells are known to contribute to motor neuron loss in ALS through a non-cell autonomous mechanism. In this study, we examined the non-cell autonomous role of wild type and mutant HSPB1 in an astrocyte-motor neuron co-culture model system of ALS. Astrocyte-specific overexpression of wild type HSPB1 was sufficient to attenuate SOD1(G93A) astrocyte-mediated toxicity in motor neurons, whereas, overexpression of mutHSPB1 failed to ameliorate motor neuron toxicity. Expression of a phosphomimetic HSPB1 mutant in SOD1(G93A) astrocytes also reduced toxicity to motor neurons, suggesting that phosphorylation may contribute to HSPB1 mediated-neuroprotection. These data provide evidence that astrocytic HSPB1 expression may play a central role in motor neuron health and maintenance.