Transcriptomic organization of the human brain in post-traumatic stress disorder

Despite extensive study of the neurobiological correlates of post-traumatic stress disorder (PTSD), little is known about its molecular determinants. Here, differential gene expression and network analyses of four prefrontal cortex subregions from postmortem tissue of people with PTSD demonstrate extensive remodeling of the transcriptomic landscape. A highly connected downregulated set of interneuron transcripts is present in the most significant gene network associated with PTSD. Integration of this dataset with genotype data from the largest PTSD genome-wide association study identified the interneuron synaptic gene ELFN1 as conferring significant genetic liability for PTSD. We also identified marked transcriptomic sexual dimorphism that could contribute to higher rates of PTSD in women. Comparison with a matched major depressive disorder cohort revealed significant divergence between the molecular profiles of individuals with PTSD and major depressive disorder despite their high comorbidity. Our analysis provides convergent systems-level evidence of genomic networks within the prefrontal cortex that contribute to the pathophysiology of PTSD in humans.

Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry

IMPORTANCE

Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders.

OBJECTIVES

To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma.

DESIGN, SETTINGS, AND PARTICIPANTS

A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma.

EXPOSURES

Genetic variants associated with primary open-angle glaucoma.

MAIN OUTCOMES AND MEASURES

Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data.

RESULTS

A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry.

CONCLUSIONS AND RELEVANCE

In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies.

Frontal Lobe Circuitry in Posttraumatic Stress Disorder

Symptoms of posttraumatic stress disorder include hyperarousal, avoidance of trauma-related stimuli, re-experiencing of trauma, and mood changes. This review focuses on the frontal cortical areas that form crucial links in circuitry pertinent to posttraumatic stress disorder symptomatology: (1) the conditioned fear extinction circuit, (2) the salience circuit, and (3) the mood circuit. These frontal areas include the ventromedial prefrontal cortex (conditioned fear extinction), the dorsal anterior cingulate and insular cortices (salience), and the lateral orbitofrontal and subgenual cingulate cortices (mood). Frontal lobe structural abnormalities in posttraumatic stress disorder, including volumetric reductions in the cingulate cortices, impact all three circuits. Functional analyses of frontal cortices in posttraumatic stress disorder show abnormal activation in all three according to task demand and emotional valence. Network analyses reveal altered amygdalo-frontal connectivity and failure to suppress the default mode network during cognitive engagement. Spine shape alterations also have been detected in the medial orbito-frontal cortex in posttraumatic stress disorder postmortem brains, suggesting reduced synaptic plasticity. Importantly, frontal lobe abnormalities in posttraumatic stress disorder extend beyond emotion-related circuits to include the lateral prefrontal cortices that mediate executive functions. In conclusion, widespread frontal lobe dysfunction in posttraumatic stress disorder provides a neurobiologic basis for the core symptomatology of the disorder, as well as for executive function impairment.

Neurosteroid Levels in the Orbital Frontal Cortex of Subjects with PTSD and Controls: A Preliminary Report

Background

Neurosteroids mediate stress signaling and have been implicated in the pathogenesis of post-traumatic stress disorder (PTSD) in both preclinical and clinical studies. Compared to controls, subjects with PTSD exhibit altered neurosteroid levels in peripheral blood and cerebrospinal fluid as well as hypoactivity in the medial orbital frontal cortex (mOFC). Therefore, the aim of this study was to compare neurosteroid levels in the mOFC of subjects with PTSD (n = 18) and controls (n = 35).

Methods

Gray matter was dissected from fresh-frozen mOFC, and levels of the neurosteroids pregnenolone, allopregnanolone, pregnanolone, epiallopregnanolone, epipregnanolone, tetrahydrodeoxycorticosterone, and androsterone were determined by gas chromatography - tandem mass spectrometry (GC/MS/MS).

Results

Analyses of unadjusted levels revealed that males with PTSD had significantly decreased levels of allopregnanolone (p = 0.03) compared to control males and females with PTSD had significantly increased levels of pregnenolone (p = 0.03) relative to control females. After controlling for age, postmortem interval, and smoking status, results showed that males with PTSD had significantly decreased levels of androsterone (t46 = 2.37, p = 0.02) compared to control males and females with PTSD had significantly increased levels of pregnanolone (t46 = -2.25, p = 0.03) relative to control females.

Conclusions

To our knowledge, this is the first report of neurosteroid levels in postmortem brain tissue of subjects with PTSD. Although replication is required in other brain regions and in a larger cohort of subjects, the results suggest a dysregulation of allopregnanolone and androsterone in males with PTSD and pregnanolone in females with PTSD in the mOFC.

Comparative evaluation of a new magnetic bead-based DNA extraction method from fecal samples for downstream next-generation 16S rRNA gene sequencing

We are colonized by a vast population of genetically diverse microbes, the majority of which are unculturable bacteria that reside within the gastrointestinal tract. As affordable, advanced next-generation sequencing technologies become more widely available, important discoveries about the composition and function of these microbes become increasingly possible. In addition to rapid advancement in sequencing technologies, automated systems have been developed for nucleic acid extraction; however, these methods have yet to be widely used for the isolation of bacterial DNA from fecal samples. Here, we adapted Promega’s Maxwell^® RSC PureFood GMO and Authentication kit for use with fecal samples and compared it to the commonly used Qiagen QIAamp^® PowerFecal^® kit. Results showed that the two approaches yielded similar measures of DNA purity and successful next-generation sequencing amplification and produced comparable composition of microbial communities. However, DNA extraction with the Maxwell^® RSC kit produced higher concentrations with a lower fecal sample input weight and took a fraction of the time compared to the QIAamp^® PowerFecal^® protocol. The results of this study demonstrate that the Promega Maxwell^® RSC system can be used for medium-throughput DNA extraction in a time-efficient manner without compromising the quality of the downstream sequencing.

SNAP-25a/b Isoform Levels in Human Brain Dorsolateral Prefrontal Cortex and Anterior Cingulate Cortex

SNAP-25 is a neurotransmitter vesicular docking protein which has been associated with brain disorders such as attention deficit hyperactivity disorder, bipolar disorder and schizophrenia. In this project, we were interested if clinical factors are associated with differential SNAP-25 expression. We examined the SNAP-25 isoform mRNA and protein levels in postmortem cortex Brodmann's area 9 (BA9) and BA24 (n = 29). Subjects were divided by psychiatric diagnosis, clinical variables including mood state in the last week of life and lifetime impulsiveness. We found affected subjects with a diagnosis of alcohol use disorder (AUD) had a lower level of SNAP-25b BA24 protein compared to those without AUD. Hispanic subjects had lower levels of SNAP-25a, b and BA9 mRNA than Anglo-American subjects. Subjects who smoked had a total pan (total) SNAP-25 BA9/BA24 ratio. Subjects in the group with a low level of anxious-psychotic symptoms had higher SNAP-25a BA24 mRNA compared to normal controls, and both the high and low symptoms groups had higher pan (total) SNAP-25 BA9/BA24 ratios than normal controls. These data expand our understanding of clinical factors associated with SNAP-25. They suggest that SNAP-25 total and isoform levels may be useful biomarkers beyond limited neurological and psychiatric diagnostic categories.

BA11 FKBP5 expression levels correlate with dendritic spine density in postmortem PTSD and controls

Genetic variants of the immunophilin FKBP5 have been implicated in susceptibility to post-traumatic stress disorder (PTSD) and other stress-related disorders. We examined the relationship between mushroom, stubby, thin and filopodial spine densities measured with Golgi staining and FKBP5 gene expression in the medial orbitofrontal cortex (BA11) in individuals diagnosed with PTSD and normal controls (n = 8/8). ANCOVA revealed PTSD cases had a significantly elevated density of stubby spines (29%, P < 0.037) and a trend for a reduction in mushroom spine density (25%, p < 0.082). Levels of FKBP5 mRNA were marginally elevated in the PTSD cases (z = 1.94, p = 0.053) and levels correlated inversely with mushroom (Spearman's rho = −0.83, p < 0.001) and overall spine density (rho = −0.75, p < 0.002) and directly with stubby spine density (rho = 0.55, p < 0.027). These data suggest that FKBP5 may participate in a cellular pathway modulating neuronal spine density changes in the brain, and that this pathway may be dysregulated in PTSD.

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The present study is one of the first human post-mortem PTSD studies to date.

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Extreme stress has robust repercussions on glucocorticoids and dendritic spine morphology in animal models.

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FKBP5, involved in glucocorticoid signaling, was inversely associated with mushroom spine density in frontal cortex.

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These findings are consistent with alterations in glucocorticoid signaling in PTSD affecting synaptic plasticity.

The enzymatic activities of brain catechol-O-methyltransferase (COMT) and methionine sulphoxide reductase are correlated in a COMT Val/Met allele-dependent fashion

AIMS

The enzyme catechol-O-methyltransferase (COMT) plays a primary role in the metabolism of catecholamine neurotransmitters and is implicated in the modulation of cognitive and emotional responses. The best characterized single nucleotide polymorphism (SNP) of the COMT gene consists of a valine (Val)-to-methionine (Met) substitution at codon 108/158. The Met-containing variant confers a marked reduction in COMT catalytic activity. We recently showed that the activity of recombinant COMT is positively regulated by the enzyme Met sulphoxide reductase (MSR), which counters the oxidation of Met residues of proteins. The current study was designed to assess whether brain COMT activity may be correlated to MSR in an allele-dependent fashion.

METHODS

COMT and MSR activities were measured from post-mortem samples of prefrontal cortices, striata and cerebella of 32 subjects by using catechol and dabsyl-Met sulphoxide as substrates, respectively. Allelic discrimination of COMT Val(108/185) Met SNP was performed using the Taqman 5'nuclease assay.

RESULTS

Our studies revealed that, in homozygous carriers of Met, but not Val alleles, the activity of COMT and MSR was significantly correlated throughout all tested brain regions.

CONCLUSION

These results suggest that the reduced enzymatic activity of Met-containing COMT may be secondary to Met sulphoxidation and point to MSR as a key molecular determinant for the modulation of COMT activity.

Distribution of venlafaxine, O-desmethylvenlafaxine, and O-desmethylvenlafaxine to venlafaxine ratio in postmortem human brain tissue

Venlafaxine (VEN) and its metabolite O-desmethylvenlafaxine (ODV) inhibit reuptake of serotonin and norepinephrine. This study examines whether VEN is differentially distributed in postmortem brain and examines relationships between brain and femoral blood concentrations from donors prescribed VEN for treatment of depression. Using high-pressure liquid chromatography-ultraviolet detection, VEN and ODV concentrations were measured in temporal, occipital, and cerebellar cortex of six postmortem brains. The ODV/VEN ratio was calculated as a relative measure of drug metabolism within each region where higher ratios indicated a greater conversion of VEN to ODV. Compared to the other regions examined, the cerebellum showed decreased VEN (p = 0.056), ODV (p = 0.006), and ODV/VEN (p = 0.027) ratios. In parts per million, VEN was higher in temporal and occipital cortex, but not cerebellum, as compared to femoral blood concentration. These observations suggest that VEN and ODV are differentially distributed in the brain, and metabolism of VEN to ODV may vary across brain regions.

Serotonin receptor, SERT mRNA and correlations with symptoms in males with alcohol dependence and suicide

OBJECTIVE

This study tested the hypothesis that abnormalities in components of the serotonin (5HT) system in the prefrontal cortex are associated with suicide in alcohol-dependent subjects. Second, we assessed the relationship of lifetime impulsivity and mood symptoms with prefrontal cortex 5-HT measures.

METHOD

Tissue was obtained from Brodmann's areas (BA) 9 and 24 in postmortem samples of individuals who were alcohol dependent with suicide (n = 5), alcohol dependent without suicide (n = 9) and normal controls (n = 5). Serotonin receptor (5HT) and serotonin reuptake transporter (SERT) mRNA were measured. Interviews with next of kin estimated lifetime impulsivity and mood symptoms in the last week of life.

RESULTS

Serotonin receptor 1A (5HT1A) mRNA in BA 9 was elevated in the alcohol dependence without suicide group compared with controls. In the alcohol dependence with suicide group, anxiety symptoms were associated with decreased BA 24 SERT mRNA and depressive symptoms with BA 9 5HT1A mRNA expression. In the alcohol dependent only group impulsivity is correlated with increased BA 9, and BA 24 serotonin receptor 2A mRNA.

CONCLUSION

Our data suggest region-specific change, rather than global serotonin blunting is involved in alcohol dependence and suicide. It also suggests that symptoms are differentially influenced by prefrontal cortex serotonin receptor mRNA levels.

Selective alterations in postsynaptic markers of chandelier cell inputs to cortical pyramidal neurons in subjects with schizophrenia

Markers of GABA neurotransmission between chandelier neurons and their synaptic targets, the axon initial segment (AIS) of pyramidal neurons, are altered in the dorsolateral prefrontal cortex (dlPFC) of subjects with schizophrenia. For example, immunoreactivity for the GABA membrane transporter (GAT1) is decreased in presynaptic chandelier neuron axon terminals, whereas immunoreactivity for the GABA(A) receptor alpha2 subunit is increased in postsynaptic AIS. To understand the nature and functional significance of these alterations, we determined the density, laminar distribution, and length of AIS immunoreactive (IR) for ankryin-G and betaIV spectrin, two proteins involved in the regulation of synapse structure and ion channel clustering at AIS, in dlPFC area 46 from 14 matched triads of subjects with schizophrenia or major depressive disorder (MDD) and normal comparison participants. The density of ankyrin-G-IR AIS in the superficial, but not in the deep, cortical layers was significantly decreased by 15-19% in the subjects with schizophrenia relative to the other participant groups. In contrast, no group differences were present in the density of betaIV spectrin-IR AIS. The length of labeled AIS did not differ across participant groups for either ankyrin-G or betaIV spectrin. The density of ankyrin-G-IR AIS was not altered in the dlPFC of macaque monkeys chronically exposed to antipsychotic medications. Given the important role of ankyrin-G in the recruitment and stabilization of sodium channels and other integral membrane proteins to AIS, our findings suggest that these processes are selectively altered in superficial layer pyramidal neurons in subjects with schizophrenia.

Postnatal development of synaptic structure proteins in pyramidal neuron axon initial segments in monkey prefrontal cortex

In the primate prefrontal cortex (PFC), the functional maturation of the synaptic connections of certain classes of gamma-aminobutyric acid (GABA) neurons is very complex. For example, the levels of both pre- and postsynaptic proteins that regulate GABA neurotransmission from the chandelier class of cortical interneurons to the axon initial segment (AIS) of pyramidal neurons undergo marked changes during both the perinatal period and adolescence in the monkey PFC. In order to understand the potential molecular mechanisms associated with these developmental refinements, we quantified the relative densities, laminar distributions, and lengths of pyramidal neuron AIS immunoreactive for ankyrin-G, betaIV spectrin, or gephyrin, three proteins involved in regulating synapse structure and receptor localization, in the PFC of rhesus monkeys ranging in age from birth through adulthood. Ankyrin-G- and betaIV spectrin-labeled AIS declined in density and length during the first 6 postnatal months, but then remained stable through adolescence and into adulthood. In contrast, the density of gephyrin-labeled AIS was stable until approximately 15 months of age and then markedly declined during adolescence. Thus, molecular determinants of the structural features that define GABA inputs to pyramidal neuron AIS in monkey PFC undergo distinct developmental trajectories with different types of changes occurring during the perinatal period and adolescence. In concert with previous data, these findings reveal a two-phase developmental process of GABAergic synaptic stability and GABA neurotransmission at chandelier cell inputs to pyramidal neurons that likely contributes to the protracted maturation of behaviors mediated by primate PFC circuitry.

Serotonin1A receptors at the axon initial segment of prefrontal pyramidal neurons in schizophrenia

OBJECTIVE

Inhibition mediated by gamma-aminobutyric acid at the axon initial segment of pyramidal neurons appears to be altered in the prefrontal cortex in schizophrenia. This study examined the densities and laminar distribution of axon initial segments labeled with an antibody against the serotonin(1A) (5-HT(1A)) receptor, which also mediates inhibitory regulation of pyramidal neurons, in subjects with schizophrenia.

METHOD

The densities and laminar distribution of axon initial segments with 5-HT(1A)-like immunoreactivity were assessed in postmortem tissue from the prefrontal cortex (Brodmann's area 46) of 14 matched triads of subjects with schizophrenia, subjects with major depressive disorder, and comparison subjects with no psychiatric disorder.

RESULTS

The relative densities of the labeled axon initial segment in both the superficial and the deep cortical layers did not differ across the three subject groups.

CONCLUSIONS

The findings do not support a role for altered serotonin transmission by means of the 5-HT(1A) receptor in dysfunction of prefrontal cortex pyramidal neurons in schizophrenia.

Postnatal development of pre- and postsynaptic GABA markers at chandelier cell connections with pyramidal neurons in monkey prefrontal cortex

The protracted postnatal maturation of the primate prefrontal cortex (PFC) is associated with substantial changes in the number of excitatory synapses on pyramidal neurons, whereas the total number of inhibitory synapses appears to remain constant. In this study, we sought to determine whether the developmental changes in excitatory input to pyramidal cells are paralleled by changes in functional markers of inhibitory inputs to pyramidal neurons. The chandelier subclass of gamma-aminobutyric acid (GABA) neurons provides potent inhibitory control over pyramidal neurons by virtue of their axon terminals, which form distinct vertical structures (termed cartridges) that synapse at the axon initial segment (AIS) of pyramidal neurons. Thus, we examined the relative densities, laminar distributions, and lengths of presynaptic chandelier axon cartridges immunoreactive for the GABA membrane transporter 1 (GAT1) or the calcium-binding protein parvalbumin (PV) and of postsynaptic pyramidal neuron AIS immunoreactive for the GABA(A) receptor alpha(2) subunit (GABA(A) alpha(2)) in PFC area 46 of 38 rhesus monkeys (Macaca mulatta). From birth through 2 years of age, the relative densities and laminar distributions of these three markers exhibited different trajectories, suggesting developmental shifts in the weighting of at least some factors that determine inhibition at the AIS. In contrast, from 2 to 4 years of age, all three markers exhibited similar declines in density and length that paralleled the periadolescent pruning of excitatory synapses to pyramidal neurons. Across development, the predominant laminar location of PV-labeled cartridges and GABA(A) alpha(2)-immunoreactive AIS shifted from the middle to superficial layers, whereas the laminar distribution of GAT1-positive cartridges did not change. Together, these findings suggest that the maturation of inhibitory inputs to the AIS of PFC pyramidal neurons is a complex process that may differentially affect the firing patterns of subpopulations of pyramidal neurons at specific postnatal time points.

Lamina-specific deficits in parvalbumin-immunoreactive varicosities in the prefrontal cortex of subjects with schizophrenia: evidence for fewer projections from the thalamus

OBJECTIVE

Neuronal number in the mediodorsal thalamic nucleus, the principal source of thalamic projections to the prefrontal cortex, has been reported to be lower in subjects with schizophrenia. The authors tested the hypothesis that schizophrenia is associated with a selective deficit in a marker of thalamic axon terminals in the middle layers of the prefrontal cortex, the primary zone of termination of thalamic axons.

METHOD

The densities of parvalbumin-immunoreactive varicosities (putative axon terminals) were determined in the superficial and middle layers of prefrontal cortex area 9 from 20 matched pairs of subjects with schizophrenia and normal comparison subjects. In order to determine the specificity of these observations, similar studies were conducted in subjects with major depressive disorder and in monkeys after 9-12 months of haloperidol treatment.

RESULTS

The relative densities of parvalbumin-immunoreactive varicosities did not differ between schizophrenic and comparison subjects in the superficial layers. However, in the middle layers, mean varicosity density was significantly lower (24% difference) in the subjects with schizophrenia. In contrast, neither subjects with major depressive disorder nor haloperidol-treated monkeys exhibited a middle-layer density of parvalbumin-immunoreactive varicosities that was lower than that of their matched comparison groups.

CONCLUSIONS

Although not definitive, these findings are consistent with the hypothesis of fewer projections from the mediodorsal thalamic nucleus to the prefrontal cortex in schizophrenic subjects and thus converge with other lines of evidence demonstrating an abnormality in thalamo-prefrontal cortical circuitry in persons with schizophrenia.

Cystoid macular edema associated with latanoprost in aphakic and pseudophakic eyes

PURPOSE

To describe four patients who developed cystoid macular edema shortly after onset of treatment with latanoprost.

METHOD

Retrospective review of medical records of patients with open-angle glaucoma who developed cystoid macular edema shortly after starting latanoprost.

RESULTS

The use of topical latanoprost was temporally related to the development of cystoid macular edema in four patients (six eyes; two aphakic eyes and four pseudophakic eyes). Cystoid macular edema resolved in all patients after latanoprost was discontinued.

CONCLUSIONS

Cystoid macular edema is a potential complication of latanoprost therapy. Further observations are needed to determine if the risk of cystoid macular edema is limited to or greatest in patients who are pseudophakic or aphakic.

Meeting the challenges of critical care obstetrics in today's health care system: collaborative education and practice strategies

The transformation of health care in the United States necessitates developing creative strategies to provide quality and cost-effective care for the critically ill obstetric patient population. A discussion of the care of these patients is presented in a multidisciplinary framework, using a case study to illustrate the management process. The significance of contributions and collaboration of advanced practice nurses in perinatology and critical care in the care management of the critically ill obstetric patient is described. Such strategies as location of the patient and educational preparation for nurses caring for these complex patients are offered for consideration. Implications are described and recommendations are made for administrative and clinical practice.