Faculty Bibliography

Unbiased high-throughput sequencing (HTS) has enabled new insights into the diversity of agents implicated in central nervous system (CNS) infections. The addition of positive selection capture methods to HTS has enhanced the sensitivity while reducing sequencing costs and the complexity of bioinformatic analysis. Here we report the use of virus capture-based sequencing for vertebrate viruses (VirCapSeq-VERT) and bacterial capture sequencing (BacCapSeq) in investigating CNS infections. Thirty-four samples were categorized: (1) patients with definitive CNS infection by routine testing; (2) patients meeting clinically the Brighton criteria (BC) for meningoencephalitis; (3) patients with presumptive infectious etiology highest on the differential. RNA extracts from cerebrospinal fluid (CSF) were used for VirCapSeq-VERT, and DNA extracts were used for BacCapSeq analysis. Among 8 samples from known CNS infections in group 1, VirCapSeq and BacCapSeq confirmed 3 expected diagnoses (42.8%), were negative in 2 (25%), yielded an alternative result in 1 (11.1%), and did not detect 2 expected negative pathogens. The confirmed cases identified HHV-6, HSV-2, and VZV while the negative samples included JCV and HSV-2. In groups 2 and 3, 11/26 samples (42%) were positive for at least one pathogen; however, 27% of the total samples (7/26) were positive for commensal organisms. No microbial nucleic acids were detected in negative control samples. HTS showed limited promise for pathogen identification in presumed CNS infectious diseases in our small sample. Before conducting larger-scale prospective studies to assess the clinical value of this novel technique, clinicians should understand the benefits and limitations of using this modality.

BACKGROUND/UNASSIGNED:Unbiased high-throughput sequencing (HTS) has enabled new insights into the diversity of agents implicated in central nervous system (CNS) infections. The addition of positive selection capture methods to HTS has enhanced the sensitivity while reducing sequencing costs and complexity of bioinformatic analysis. Here we report the use of virus capture based sequencing for vertebrate viruses (VirCapSeq-VERT) and bacterial capture sequencing (BacCapSeq) in investigating CNS infections. DESIGN/METHODS/UNASSIGNED:Thirty-four samples were categorized: (1) Patients with definitive CNS infection by routine testing; (2) Patients meeting clinically Brighton Criteria (BC) for meningoencephalitis (3) Patients with presumptive infectious etiology highest on the differential. RNA extracts from cerebrospinal fluid (CSF) were used for VirCapSeq-VERT and DNA extracts were used for BacCapSeq analysis. RESULTS/UNASSIGNED:Among 8 samples from known CNS infections in group 1, VirCapSeq and BacCapSeq confirmed 3 expected diagnoses (42.8%), were negative in 2 (25%), yielded an alternative result in 1 (11.1%), and did not detect 2 expected negative pathogens. The confirmed cases identified HHV-6, HSV-2, and VZV while the negative samples included JCV and HSV-2. In groups 2 and 3,11/26 samples (42%) were positive for at least one pathogen, however 27% of the total samples (7/26) were positive for commensal organisms. No microbial nucleic acids were detected in negative control samples. CONCLUSIONS/UNASSIGNED:HTS showed limited promise for pathogen identification in presumed CNS infectious diseases in our small sample. Before conducting larger-scale prospective studies to assess clinical value of this novel technique, clinicians should understand benefits and limitations of using this modality.

OBJECTIVES:Early presentation and workup for acute infectious (IE) and autoimmune encephalitis (AE) are similar. This study aims to identify routine laboratory markers at presentation that are associated with IE or AE. METHODS:This was a multi-center retrospective study at three tertiary care hospitals in New York City analyzing demographic and clinical data from patients diagnosed with definitive encephalitis based on a confirmed pathogen and/or autoantibody and established criteria for clinical syndromes. RESULTS:Three hundred and thirty-three individuals with confirmed acute meningoencephalitis were included. An infectious-nonbacterial (NB) pathogen was identified in 151/333 (45.40%), bacterial pathogen in 95/333 (28.50%), and autoantibody in 87/333 (26.10%). NB encephalitis was differentiated from AE by the presence of fever (NB 62.25%, AE 24.10%; p < 0.001), higher CSF white blood cell (WBC) (median 78 cells/μL, 8.00 cells/μL; p < 0.001), higher CSF protein (76.50 mg/dL, 40.90 mg/dL; p < 0.001), lower CSF glucose (58.00 mg/dL, 69.00 mg/dL; p < 0.001), lower serum WBC (7.80 cells/μL, 9.72 cells/μL; p < 0.050), higher erythrocyte sedimentation rate (19.50 mm/HR, 13.00 mm/HR; p < 0.05), higher C-reactive protein (6.40 mg/L, 1.25 mg/L; p = 0.005), and lack of antinuclear antibody titers (>1:40; NB 11.54%, AE 32.73%; p < 0.001). CSF-to-serum WBC ratio was significantly higher in NB compared to AE (NB 11.3, AE 0.99; p < 0.001). From these findings, the association of presenting with fever, CSF WBC ≥50 cells/μL, and CSF protein ≥75 mg/dL was explored in ruling-out AE. When all three criteria are present, an AE was found to be highly unlikely (sensitivity 92%, specificity 75%, negative predictive value 95%, and positive predictive value 64%). INTERPRETATIONS:Specific paraclinical data at initial presentation may risk stratify which patients have an IE versus AE.

Depression is a leading cause of disease burden, yet current therapies fully treat <50% of affected individuals. Increasing evidence implicates epigenetic mechanisms in depression and antidepressant action. Here we examined a possible role for the DNA dioxygenase, ten-eleven translocation protein 1 (TET1), in depression-related behavioral abnormalities. We applied chronic social defeat stress, an ethologically validated mouse model of depression-like behaviors, and examined Tet1 expression changes in nucleus accumbens (NAc), a key brain reward region. We show decreased Tet1 expression in NAc in stress-susceptible mice only. Surprisingly, selective knockout of Tet1 in NAc neurons of adult mice produced antidepressant-like effects in several behavioral assays. To identify Tet1 targets that mediate these actions, we performed RNAseq on NAc after conditional deletion of Tet1 and found that immune-related genes are the most highly dysregulated. Moreover, many of these genes are also upregulated in the NAc of resilient mice after chronic social defeat stress. These findings reveal a novel role for TET1, an enzyme important for DNA hydroxymethylation, in the brain's reward circuitry in modulating stress responses in mice. We also identify a subset of genes that are regulated by TET1 in this circuitry. These findings provide new insight into the pathophysiology of depression, which can aid in future antidepressant drug discovery efforts.

Decreased medial prefrontal cortex (mPFC) neuronal activity is associated with social defeat-induced depression- and anxiety-like behaviors in mice. However, the molecular mechanisms underlying the decreased mPFC activity and its prodepressant role remain unknown. We show here that induction of the transcription factor ΔFosB in mPFC, specifically in the prelimbic (PrL) area, mediates susceptibility to stress. ΔFosB induction in PrL occurred selectively in susceptible mice after chronic social defeat stress, and overexpression of ΔFosB in this region, but not in the nearby infralimbic (IL) area, enhanced stress susceptibility. ΔFosB produced these effects partly through induction of the cholecystokinin (CCK)-B receptor: CCKB blockade in mPFC induces a resilient phenotype, whereas CCK administration into mPFC mimics the anxiogenic- and depressant-like effects of social stress. We previously found that optogenetic stimulation of mPFC neurons in susceptible mice reverses several behavioral abnormalities seen after chronic social defeat stress. Therefore, we hypothesized that optogenetic stimulation of cortical projections would rescue the pathological effects of CCK in mPFC. After CCK infusion in mPFC, we optogenetically stimulated mPFC projections to basolateral amygdala or nucleus accumbens, two subcortical structures involved in mood regulation. Stimulation of corticoamygdala projections blocked the anxiogenic effect of CCK, although no effect was observed on other symptoms of social defeat. Conversely, stimulation of corticoaccumbens projections reversed CCK-induced social avoidance and sucrose preference deficits but not anxiogenic-like effects. Together, these results indicate that social stress-induced behavioral deficits are mediated partly by molecular adaptations in mPFC involving ΔFosB and CCK through cortical projections to distinct subcortical targets.