CSF-Neurofilament Light Chain Levels in NMDAR and LGI1 Encephalitis: A National Cohort Study

Background and ObjectivesThe two most common autoimmune encephalitides (AE), N-methyl-D-Aspartate receptor (NMDAR) and Leucine-rich Glioma-Inactivated 1 (LGI1) encephalitis, have been known for more than a decade. Nevertheless, no well-established biomarkers to guide treatment or estimate prognosis exist. Neurofilament light chain (NfL) has become an unspecific screening marker of axonal damage in CNS diseases, and has proven useful as a diagnostic and disease activity marker in neuroinflammatory diseases. Only limited reports on NfL in AE exist. We investigated NfL levels at diagnosis and follow-up in NMDAR and LGI1-AE patients, and evaluated the utility of CSF-NfL as a biomarker in AE.MethodsPatients were included from the National Danish AE cohort (2009-present) and diagnosed based upon autoantibody positivity and diagnostic consensus criteria. CSF-NfL was analyzed by single molecule array technology. Clinical and diagnostic information was retrospectively evaluated and related to NfL levels at baseline and follow-up. NMDAR-AE patients were subdivided into: idiopathic/teratoma associated or secondary NMDAR-AE (post-viral or concomitant with malignancies/demyelinating disease).ResultsA total of 74 CSF samples from 53 AE patients (37 NMDAR and 16 LGI1 positive) were included in the study. Longitudinal CSF-NfL levels was measured in 21 patients. Median follow-up time was 23.8 and 43.9 months for NMDAR and LGI1-AE respectively. Major findings of this study are: i) CSF-NfL levels were higher in LGI1-AE than in idiopathic/teratoma associated NMDAR-AE at diagnosis; ii) CSF-NfL levels in NMDAR-AE patients distinguished idiopathic/teratoma cases from cases with other underlying etiologies (post-viral or malignancies/demyelinating diseases) and iii) Elevated CSF-NfL at diagnosis seems to be associated with worse long-term disease outcomes in both NMDAR and LGI1-AE.DiscussionCSF-NfL measurement may be beneficial as a prognostic biomarker in NMDAR and LGI1-AE, and high CSF-NfL could foster search for underlying etiologies in NMDAR-AE. Further studies on larger cohorts, using standardized methods, are warranted.

Squalene decreased malondialdehyde level of diabetic rats

Squalene, a precursor for the secondary metabolite synthesis, is synthesized in animals, bacteria, fungi and plants. It has been reported to have some biological activities, one of which is as an antioxidant. This study aimed to evaluate the effect of squalene on malondialdehyde (MDA) level, an antioxidant activity marker, in diabetic rats. Diabetes type II was induced by a high-fat diet with low dose streptozotocin (30 mg/kg) intraperitoneally. A total of 12 diabetic rats were divided into 3 groups and served once daily for 14 days as follows; Group I (Squalene (S) 160 mg/kg), Group II (Metformin (M) 45 mg/kg) and Group III Aquades (DC) 10 ml/kg). MDA level were measured using Elisa method. Data were analyzed using Kruskall Wallis and Mann-Whitney as post hoc test. The results showed that MDA level in both S- (8.50 ± 1.40 µmol/L) and M- (7.74 ± 1.63 µmol/L) were lower than DC-treated groups (12.82± 2.86 µmol/L). Statistically, significant different were found between S- and DC- as well as Sand M-treated groups (p< 0.05). This study suggested that squalene able to decrease MDA level in type II diabetic rats.

∆9-Tetrahydrocannabinol Self-Administration Induces Cell-Type Specific Adaptations and cFOS Expression in the Nucleus Accumbens Core

Given that 30% of chronic cannabis users develop cannabis use disorder (CUD), it is critical to identify neuroadaptations that contribute to this disease. The nucleus accumbens core (NAcore) is important for drug seeking and ~ 90% of all NAcore neurons are divided into D1- and D2-medium spiny neurons (MSNs) that serve opposing roles in drug seeking. Drugs of abuse induce D1- and D2-MSN specific adaptations but whether ∆9-tetrahydrocannabinol (THC) use initiates similar neuroadaptations is unknown. D1- and D2-Cre transgenic rats were transfected with Cre-dependent reporters and trained to self-administer THC + cannabidiol (THC + CBD). After extinction training dendritic spine morphology, glutamate transmission, CB1R function and cFOS expression were quantified. We found that extinction from THC + CBD induced a loss of large spine heads in D1- but not D2-MSNs and a commensurate reduction in glutamate synaptic transmission. Also, CB1R function was impaired on glutamatergic synapses onto D1-MSNs and this was paralleled by an augmented capacity to potentiate glutamate transmission in D1-MSNs. CB1R function and glutamate synaptic transmission on D2-MSN synapses were unaffected by THC + CBD use. Using cFOS expression as an activity marker, we found that D1-MSNs activity remained unchanged after extinction from THC + CBD but significantly increased after 60 minutes cue-induced drug seeking. Surprisingly, the percentage of D2-MSNs expressing cFOS decreased after extinction from THC + CBD and this decrease was restored by drug cues. Thus, glutamatergic adaptations in D1-MSNs partially predict activity changes and pose modulating CB1R function that is down-regulated selectively at D1-MSN synapses as a potential treatment strategy for CUD.

Green spotted puffer can detect an almost nontoxic TTX analog odor using crypt olfactory sensory neurons

Tetrodotoxin (TTX) is a well-known neurotoxin that functions as a defense substance for toxic puffers. Several behavioral studies reported that TTX attracts toxic puffers belonging to the genus Takifugu. Although our electrophysiological and behavioral studies showed that a TTX analog, 5,6,11-trideoxyTTX, acts as an olfactory chemoattractant for grass puffers (Takifugu alboplumbeus), it is unclear whether toxic puffers are commonly attracted to 5,6,11-trideoxyTTX, and which types of olfactory sensory neurons (OSNs) detect 5,6,11-trideoxyTTX. Here we investigated whether green spotted puffer (Dichotomyctere nigroviridis), a phylogenetically different species from the grass puffer, is attracted to 5,6,11-trideoxyTTX. Administration of 5,6,11-trideoxyTTX attracted green spotted puffers, but TTX or Vehicle did not. Furthermore, immunohistochemistry of the olfactory epithelium exposed to 5,6,11-trideoxyTTX with an antibody against phosphorylated ribosomal protein S6 (pS6), a neuronal activity marker, labeled oval cells with apical invagination. Such oval cells were also labeled by the antibody against S100, a specific marker of crypt OSNs. Thus, our results suggest that 5,6,11-trideoxyTTX acts as an olfactory chemoattractant that is detected by crypt-type OSNs in the olfactory epithelium of green spotted puffers. Toxic puffers may use 5,6,11-trideoxyTTX as an olfactory chemoattractant involved in reproduction and parental care or as an olfactory cue of TTX- bearing organisms for effective toxification.

The analysis of secondary AA-amyloidosis current etiology and its influence on the approaches for diagnosis and treatment

Aim. To investigate an influence of the currently changed etiologic structure of AA-amyloidosis on the diagnosis and treatment tactics. Materials and methods. In 110 patients with АА-amyloidosis followed during full disease duration (1 month 29 years) etiology, clinical manyfestations and approaches to diagnose and treatment of AA-amyloidosis were evaluated. With ELISA levels of amyloid precursor acute phase inflammation reactant SAA and neutrophil activity marker S100A12 were measured. Results. Among the most common causes of AA-amyloidosis at the present stage, in addition to RA (40.3%), a significant place is occupied by a group of diseases with a predominantly autoinflammatory mechanism (53.73%). To confirm the autoinflammatory mechanism of the predisposing disease it is recommended to study a highly sensitive parameter serum protein S100A12. An effective marker of the risk of AA-amyloidosis progression, especially in patients with subclinical activity of inflammatory disease, is a high level of production of amyloidogenic protein-a precursor of SAA.

Role of ventral subiculum neuronal ensembles in incubation of oxycodone craving after electric barrier-induced voluntary abstinence

We recently developed a rat model of incubation of oxycodone craving where opioid seeking progressively increases after voluntary suppression of drug self-administration by adverse consequences of drug seeking. Here, we studied the role of ventral subiculum (vSub) neuronal ensembles in this incubation, using the activity marker Fos, muscimol-baclofen (GABAergic agonists) inactivation, and Daun02 chemogenetic inactivation.We trained Sprague-Dawley or Fos-lacZ transgenic male and female rats to self-administer oxycodone (0.1 mg/kg/infusion, 6-h/d) for 14 days. The rats were then exposed for 14 days to an electric barrier of increasing intensity (0.1 to 0.4 mA) near the drug-paired lever that caused voluntary abstinence or were exposed to 14 days of forced abstinence. We tested Sprague-Dawley rats for relapse to oxycodone seeking without shock and drug on abstinence day 15 and extracted their brains for Fos-immunohistochemistry, or tested them after vSub vehicle or muscimol-baclofen injections on abstinence days 1 and 15. We performed Daun02 inactivation of relapse-activated vSub Fos neurons in Fos-lacZ transgenic rats on abstinence day 15 and then tested them for relapse on abstinence day 18.Relapse after electric barrier-induced abstinence increased Fos expression in vSub. Muscimol-baclofen inactivation or Daun02 selective inactivation of vSub Fos-expressing neuronal ensembles decreased “incubated” oxycodone seeking after voluntary abstinence. Muscimol-baclofen vSub inactivation had no effect on non-incubated opioid seeking on abstinence day 1 or incubation after forced abstinence.Our results demonstrate a selective role of vSub neuronal ensembles in incubation of opioid craving after cessation of drug self-administration by adverse consequences of drug seeking.Significance statementHigh relapse rate is a cardinal feature of opioid addiction and a major impediment for successful treatment. In humans, abstinence is often self-imposed, and relapse typically involves a conflict situation between the desire to experience the drug’s rewarding effects and negative consequences of drug seeking. To mimic this human condition, we recently introduced a rat model of incubation of oxycodone craving after electric barrier-induced voluntary abstinence. Here, we used the activity marker Fos, muscimol-baclofen (GABAergic agonists) inactivation, and Daun02 chemogenetic inactivation to demonstrate a selective role of vSub neuronal ensembles in incubation of oxycodone craving after electric barrier-induced voluntary abstinence, but not in incubation of opioid craving after forced abstinence or non-incubated opioid seeking during early abstinence.

Agomelatine Softens Depressive-Like Behavior through the Regulation of Autophagy and Apoptosis

Depression is a common and disabling mental disorder with high recurrence rate. Searching for more effective treatments for depression is a long-standing primary objective in neuroscience. Agomelatine (AGO) was reported as an antidepressant with unique pharmacological effects. However, its effects and the underlying mechanism are still unclear. In this study, we sought to evaluate the antidepressant effects of AGO on the chronic restraint stress (CRS) mouse model and preliminarily investigate its effects on the gut microbial metabolites. The CRS model mice were established in 28 days with AGO (60 mg/kg/day, by oral) or fluoxetine (15 mg/kg/day, by oral) administration. The number of behavioral tests was conducted to evaluate the effect of AGO on depression-like behavior alleviation. Meanwhile, the expression of the BDNF/TrkB/pERK signaling pathway, apoptosis, autophagy, and inflammatory protein markers were assessed using western blot and immunofluorescence. Our findings show that AGO can attenuate the depressive-like behavior that significantly appeared in both sucrose preference and forced swimming tests. Additionally, a noticeable upregulation of autophagy including Beclin1 and LC3II, microglial activity marker Iba-1, and BDNF/TrkB/pERK signaling pathways are indicated. An obvious decreased expression of NF-κB, iNOS, and nNOS as well as apoptosis including Bax is observed in AGO administration mice. On the other hand, we found that AGO impacted the rebalancing of short-chain fatty acids (SCFAs) in mouse feces. Altogether, these findings suggest that AGO can exert antidepressant effects in a different molecular mechanism.

Conversion of Rutin, a Prevalent Dietary Flavonol, by the Human Gut Microbiota

The gut microbiota plays a pivotal role in the conversion of dietary flavonoids, which can affect their bioavailability and bioactivity and thereby their health-promoting properties. The ability of flavonoids to metabolically-activate the microbiota has, however, not been systematically evaluated. In the present study, we used a fluorescence-based single-cell activity measure [biorthogonal non-canonical ammino acid-tagging (BONCAT)] combined with fluorescence activated cell sorting (FACS) to determine which microorganisms are metabolically-active after amendment of the flavonoid rutin. We performed anaerobic incubations of human fecal microbiota amended with rutin and in the presence of the cellular activity marker L-azidohomoalanine (AHA) to detect metabolically-active cells. We found that 7.3% of cells in the gut microbiota were active after a 6 h incubation and 26.9% after 24 h. We then sorted BONCAT-positive cells and observed an enrichment of Lachnospiraceae (Lachnoclostridium and Eisenbergiella), Enterobacteriaceae, Tannerellaceae, and Erysipelotrichaceae species in the rutin-responsive fraction of the microbiota. There was marked inter-individual variability in the appearance of rutin conversion products after incubation with rutin. Consistent with this, there was substantial variability in the abundance of rutin-responsive microbiota among different individuals. Specifically, we observed that Enterobacteriaceae were associated with conversion of rutin into quercetin-3-glucoside (Q-glc) and Lachnospiraceae were associated with quercetin (Q) production. This suggests that individual microbiotas differ in their ability to metabolize rutin and utilize different conversion pathways.

Kisspeptin-1 regulates forebrain dopaminergic neurons in the zebrafish

The habenula is a phylogenetically conserved epithalamic structure, which conveys negative information via inhibition of mesolimbic dopamine neurons. We have previously shown the expression of kisspeptin (Kiss1) in the habenula and its role in the modulation of fear responses in the zebrafish. In this study, to investigate whether habenular Kiss1 regulates fear responses via dopamine neurons in the zebrafish, Kiss1 peptides were intracranially administered close to the habenula, and the expression of dopamine-related genes (th1, th2 and dat) were examined in the brain using real-time PCR and dopamine levels using LC–MS/MS. th1 mRNA levels and dopamine levels were significantly increased in the telencephalon 24-h and 30-min after Kiss1 administration, respectively. In fish administered with Kiss1, expression of neural activity marker gene, npas4a and kiss1 gene were significantly decreased in the ventral habenula. Application of neural tracer into the median raphe, site of habenular Kiss1 neural terminal projections showed tracer-labelled projections in the medial forebrain bundle towards the telencephalon where dopamine neurons reside. These results suggest that Kiss1 negatively regulates its own neuronal activity in the ventral habenula via autocrine action. This, in turn affects neurons of the median raphe via interneurons, which project to the telencephalic dopaminergic neurons.