Sulfotransferase 2B1b, Sterol Sulfonation, and Disease.

The primary function of human sulfotransferase 2B1b (SULT2B1b) is to sulfonate cholesterol and closely related sterols. SULT2B1b sterols perform a number of essential cellular functions. Many are signaling molecules whose activities are redefined by sulfonation-allosteric properties are switched "on" or "off," agonists are transformed into antagonists, and vice versa. Sterol sulfonation is tightly coupled to cholesterol homeostasis, and sulfonation imbalances are causally linked to cholesterol-related diseases including certain cancers, Alzheimer disease, and recessive X-linked ichthyosis-an orphan skin disease. Numerous studies link SULT2B1b activity to disease-relevant molecular processes. Here, these multifaceted processes are integrated into metabolic maps that highlight their interdependence and how their actions are regulated and coordinated by SULT2B1b oxysterol sulfonation. The maps help explain why SULT2B1b inhibition arrests the growth of certain cancers and make the novel prediction that SULT2B1b inhibition will suppress production of amyloid ß (Aß) plaques and tau fibrils while simultaneously stimulating Aß plaque phagocytosis. SULT2B1b harbors a sterol-selective allosteric site whose structure is discussed as a template for creating inhibitors to regulate SULT2B1b and its associated biology. SIGNIFICANCE STATEMENT: Human sulfotransferase 2B1b (SULT2B1b) produces sterol-sulfate signaling molecules that maintain the homeostasis of otherwise pro-disease processes in cancer, Alzheimer disease, and X-linked ichthyosis-an orphan skin disease. The functions of sterol sulfates in each disease are considered and codified into metabolic maps that explain the interdependencies of the sterol-regulated networks and their coordinate regulation by SULT2B1b. The structure of the SULT2B1b sterol-sensing allosteric site is discussed as a means of controlling sterol sulfate biology.

Sterol-activated amyloid beta fibril formation.

The metabolic processes that link Alzheimer's disease (AD) to elevated cholesterol levels in the brain are not fully defined. Amyloid beta (Aß) plaque accumulation is believed to begin decades prior to symptoms and to contribute significantly to the disease. Cholesterol and its metabolites accelerate plaque formation through as-yet-undefined mechanisms. Here, the mechanism of cholesterol (CH) and cholesterol 3-sulfate (CS) induced acceleration of Aß42 fibril formation is examined in quantitative ligand binding, Aß42 fibril polymerization, and molecular dynamics studies. Equilibrium and pre-steady-state binding studies reveal that monomeric Aß42•ligand complexes form and dissociate rapidly relative to oligomerization, that the ligand/peptide stoichiometry is 1-to-1, and that the peptide is likely saturated in vivo. Analysis of Aß42 polymerization progress curves demonstrates that ligands accelerate polymer synthesis by catalyzing the conversion of peptide monomers into dimers that nucleate the polymerization reaction. Nucleation is accelerated ∼49-fold by CH, and ∼13,000-fold by CS - a minor CH metabolite. Polymerization kinetic models predict that at presumed disease-relevant CS and CH concentrations, approximately half of the polymerization nuclei will contain CS, small oligomers of neurotoxic dimensions (∼12-mers) will contain substantial CS, and fibril-formation lag times will decrease 13-fold relative to unliganded Aß42. Molecular dynamics models, which quantitatively predict all experimental findings, indicate that the acceleration mechanism is rooted in ligand-induced stabilization of the peptide in non-helical conformations that readily form polymerization nuclei.

Comparison of open thoracoabdominal repair for chronic aortic dissections and aneurysms.

OBJECTIVE: Aortic dissection is common in patients undergoing open surgical repair of thoracoabdominal aortic aneurysms (TAAAs). Most often, dissection is chronic and is associated with progressive aortic dilatation. Because contemporary outcomes in chronic dissection are not clearly understood, we compared patient characteristics and outcomes after open TAAA repair between patients with chronic dissection and those with non-dissection aneurysm. METHODS: We retrospectively analyzed data from 3470 open TAAA repairs performed in a single practice. Operations were for non-dissection aneurysm in 2351 (67.8%) and chronic dissection in 1119 (32.2%). Outcomes included operative mortality and adverse events, a composite variable comprising operative death and persistent (present at discharge) stroke, paraplegia, paraparesis, and renal failure necessitating dialysis. Logistic regression identified predictors of operative mortality and adverse events. Time-to-event analyses examined survival, death, repair failure, subsequent progressive repair, and survival free of failure or subsequent repair. RESULTS: Compared with patients with non-dissection aneurysm, those with chronic dissection were younger, had fewer atherosclerotic risk factors, and were more likely to have heritable thoracic aortic disease and undergo extent II repair. The operative mortality rate was 8.5% (n = 296) overall and was higher in non-dissection aneurysm patients (n = 217; 9.2%) than in chronic dissection patients (n = 79; 7.1%; P = .03). Adverse events were less frequent (P = .01) in patients with chronic dissection (n = 145; 13.0%), 22 (2.0%) of whom had persistent paraplegia. Chronic dissection was not predictive of operative mortality (P = .5) or adverse events (P = .6). Operative mortality and adverse events, respectively, were independently predicted by emergency repair (odds ratio [OR], 3.46 and 2.87), chronic kidney disease (OR, 1.74 and 1.81), extent II TAAA repair (OR, 1.44 and 1.73), increasing age (OR, 1.04/year and 1.04/year), and increasing aortic cross-clamp time (OR, 1.02/minutes and 1.02/minutes). Patients with chronic dissection had lower 10-year unadjusted mortality (42% vs 69%) but more frequent repair failure (5% vs 3%) and subsequent repair for progressive aortic disease (11% vs 5%) than patients with non-dissection aneurysm (P < .001); these differences were no longer statistically significant after adjustment. CONCLUSIONS: Outcomes of open TAAA repair vary by aortic disease type. Emergency repairs and atherosclerotic diseases most commonly occur in patients with non-dissection aneurysm and independently predict operative mortality. Repair of chronic dissection is associated with low rates of adverse events, including operative mortality and persistent paraplegia, along with reasonable late survival and good durability. However, patients with chronic dissection tend to more commonly undergo subsequent repair to treat progressive aortic disease, which emphasizes the need for robust long-term imaging surveillance protocols.

A Review of WIfI Clinical Staging to Predict Outcomes in Patients With Threatened Limbs.

The Society for Vascular Surgery Wound, Ischemia, and foot Infection's (WIfI's) threatened limb classification system serves to comprehensively assess the severity of disease in patients with chronic limb-threatening ischemia by identifying and grading the main factors that place the threatened limb at greatest risk: wound severity, ischemic burden, and presence of infection. Each of these 3 factors is graded and the limb placed into a clinical stage, with increasing stage associated with severity of limb threat and predicted risk of major limb amputation at 1 year. Globally, there is a growing body of evidence reported from multiple institutions that has assessed amputation rates and wound-healing outcomes following revascularization in patients with WIfI clinical staging. Risk of major amputation at 1 year is low in clinical stage 1, moderate in stages 2 and 3, and high in stage 4. Higher clinical stages are associated with prolonged time to wound healing, while 1-year wound healing rates consistently decrease with increasing clinical stage. Additional avenues of investigation utilizing WIfI as an objective clinical staging tool have yielded new insights into which patients benefit from revascularization, complexity of care, hospital length of stay, quality of life, ethnic and socioeconomic disparities, as well as spurred interest in other modalities of assessing limb perfusion and their possible clinical utility. Ongoing study and refinement of WIfI grading and clinical staging will continue to improve its prognostic utility.

Functional Analysis of RE1 Silencing Transcription Factor as a Putative Tumor Suppressor in Human Endometrial Cancer.

Uterine cancer is the most common gynecologic malignancy in the United States, with endometrioid endometrial adenocarcinoma (EC) being the most common histologic sub-type. Considering the molecular classifications of EC, efforts have been made to identify additional biomarkers that can assist in diagnosis, prognosis, and individualized therapy. We sought to explore the relationship of Repressor Element 1 (RE1) silencing transcription factor (REST), which downregulates neuronal genes in non-neuronal tissue, along with matrix metalloproteinase-24 (MMP24) and EC. We analyzed the expression of REST and MMP24 in 31 cases of endometrial cancer and 16 controls. We then explored the baseline expression of REST and MMP24 in two EC cell lines (Ishikawa and HEC-1-A) compared to a benign cell line (t-HESC) and subsequently evaluated proliferation, migration, and invasion in the setting of loss of REST gene expression. REST and MMP24 expression were significantly lower in human EC samples compared to control samples. REST was highly expressed in EC cell lines, but decreasing REST gene expression increased proliferation (FC: 1.13X, p < 0.0001), migration (1.72X, p < 0.0001), and invasion (FC: 7.77X, p < 0.05) in Ishikawa cells, which are hallmarks of cancer progression and metastasis. These findings elicit a potential role for REST as a putative tumor suppressor in EC.

Contemporary Medical Management of Peripheral Arterial Disease.

PURPOSE: Peripheral arterial disease (PAD) is characterized by atherosclerotic arterial occlusive disease of the lower extremities and is associated with an increased risk of major adverse cardiovascular events (MACE) in addition to disabling clinical sequelae, including intermittent claudication and chronic limb-threatening ischemia (CLTI). Given the growing burden of disease, knowledge of modern practices to prevent MACE and major adverse limb events (MALE) is essential. This review article examines evidence for medical management of PAD and its associated risk factors, as well as wound prevention and care. METHODS: A thorough review of the literature was performed, with attention to evidence for the management of modifiable atherosclerotic risk factors, claudication symptoms, wound prevention, and wound care. RESULTS: Contemporary management of PAD requires a multi-faceted approach to care, with medical optimization of smoking, hypertension, hyperlipidemia, and diabetes mellitus. The use of supervised exercise therapy for intermittent claudication is highlighted. The anatomic disease patterns of smoking and diabetes mellitus are discussed further, and best practices for diabetic foot ulcer prevention, including offloading footwear, are described. Quality wound care is essential in this patient population and involves strategic use of debridement, wound-healing adjuncts, and skin substitutes, when appropriate. CONCLUSION: The objective of medical management of PAD is to reduce the risk of MACE and MALE. Atherosclerotic risk factor optimization, appropriate wound care, and management of diabetic foot ulcers, foot infections, gangrene, and chronic, non-healing wounds are critical components of PAD care. Interdisciplinary care is essential to coordinate care, leverage expertise, and improve outcomes.

Cost-Conscious Colposcopy: A Single-Institution Review of Biopsy Submission Practices and Outcomes.

OBJECTIVE: Distribution of cervical dysplasia may influence approach for excisional procedures. Separating colposcopy biopsies into multiple specimen cups for pathologic evaluation incurs additional costs. The authors aimed to determine whether the practice of separating biopsy specimens impacts patient outcomes. METHODS: A retrospective review of all colposcopy cases from a single institution was performed. A total of 1,331 cases were reviewed from January 1, 2017, to December 31, 2019. Multibiopsy cohorts were separated by number of specimen cups received by pathology (single or multiple). Cohorts were compared for histology, need for excisional procedure, and final excisional pathology results. Specimen processing fees were acquired from the Department of Pathology ($70/specimen). Statistical analysis performed on MINITAB using Pearson chi-square and Fisher exact tests. RESULTS: Excisional procedures were required by 30.4% (86/283) of multiple specimen submissions compared with 28.2% (154/547) of single specimen cup submissions ( p = .50). There was a higher, although not statistically significant, rate of additional procedures in the multiple specimen cup cohort (8.8 vs 2.9% [ p = .08]). Malignancy diagnosis was equivalent in each cohort. Cost analysis revealed adopting a single specimen cup model would reduce costs up to approximately $30,000/year. CONCLUSIONS: Patient outcomes were not improved by the practice of submitting multiple specimen cups. Given the additional cost associated with separating specimens, the authors recommend during routine colposcopy that all cervical biopsies be sent for evaluation as a single pathology specimen unless a lesion of concern is identified in an area not normally excised during traditional excisional procedures.

The N-Terminus of Human Sulfotransferase 2B1b─a Sterol-Sensing Allosteric Site.

Among human cytosolic sulfotransferases, SULT2B1b is highly specific for oxysterols─oxidized cholesterol derivatives, including nuclear-receptor ligands causally linked to skin and neurodegerative diseases, cancer and atherosclerosis. Sulfonation of signaling oxysterols redirects their receptor-binding functions, and controlling these functions is expected to prove valuable in disease prevention and treatment. SULT2B1b is distinct among the human SULT2 isoforms by virtue of its atypically long N-terminus, which extends 15 residues beyond the next longest N-terminus in the family. Here, in silico studies are used to predict that the N-terminal extension forms an allosteric pocket and to identify potential allosteres. One such allostere, quercetin, is used to confirm the existence of the pocket and to demonstrate that allostere binding inhibits turnover. The structure of the pocket is obtained by positioning quercetin on the enzyme, using spin-label-triangulation NMR, followed by NMR distance-constrained molecular dynamics docking. The model is confirmed using a combination of site-directed mutagenesis and initial-rate studies. Stopped-flow ligand-binding studies demonstrate that inhibition is achieved by stabilizing the closed form of the enzyme active-site cap, which encapsulates the nucleotide, slowing its release. Finally, endogenous oxysterols are shown to bind to the site in a highly selective fashion─one of the two immediate biosynthetic precursors of cholesterol (7-dehydrocholesterol) is an inhibitor, while the other (24-dehydrocholesterol) is not. These findings provide insights into the allosteric dialogue in which SULT2B1b participates in in vivo and establishes a template against which to develop isoform-specific inhibitors to control SULT2B1b biology.

The molecular basis of OH-PCB estrogen receptor activation.

Polychlorinated bisphenols (PCBs) continue to contaminate food chains globally where they concentrate in tissues and disrupt the endocrine systems of species throughout the ecosphere. Hydroxylated PCBs (OH-PCBs) are major PCB metabolites and high-affinity inhibitors of human estrogen sulfotransferase (SULT1E1), which sulfonates estrogens and thus prevents them from binding to and activating their receptors. OH-PCB inhibition of SULT1E1 is believed to contribute significantly to PCB-based endocrine disruption. Here, for the first time, the molecular basis of OH-PCB inhibition of SULT1E1 is revealed in a structure of SULT1E1 in complex with OH-PCB1 (4'-OH-2,6-dichlorobiphenol) and its substrates, estradiol (E2), and PAP (3'-phosphoadenosine-5-phosphosulfate). OH-PCB1 prevents catalysis by intercalating between E2 and catalytic residues and establishes a new E2-binding site whose E2 affinity and positioning are greater than and competitive with those of the reactive-binding pocket. Such complexes have not been observed previously and offer a novel template for the design of high-affinity inhibitors. Mutating residues in direct contact with OH-PCB weaken its affinity without compromising the enzyme's catalytic parameters. These OH-PCB resistant mutants were used in stable transfectant studies to demonstrate that OH-PCBs regulate estrogen receptors in cultured human cell lines by binding the OH-PCB binding pocket of SULT1E1.

Small-molecule control of neurotransmitter sulfonation.

Controlling unmodified serotonin levels in brain synapses is a primary objective when treating major depressive disorder-a disease that afflicts ∼20% of the world's population. Roughly 60% of patients respond poorly to first-line treatments and thus new therapeutic strategies are sought. To this end, we have constructed isoform-specific inhibitors of the human cytosolic sulfotransferase 1A3 (SULT1A3)-the isoform responsible for sulfonating ∼80% of the serotonin in the extracellular brain fluid. The inhibitor design includes a core ring structure, which anchors the inhibitor into a SULT1A3-specific binding pocket located outside the active site, and a side chain crafted to act as a latch to inhibit turnover by fastening down the SULT1A3 active-site cap. The inhibitors are allosteric, they bind with nanomolar affinity and are highly specific for the 1A3 isoform. The cap-stabilizing effects of the latch can be accurately calculated and are predicted to extend throughout the cap and into the surrounding protein. A free-energy correlation demonstrates that the percent inhibition at saturating inhibitor varies linearly with cap stabilization - the correlation is linear because the rate-limiting step of the catalytic cycle, nucleotide release, scales linearly with the fraction of enzyme in the cap-open form. Inhibitor efficacy in cultured cells was studied using a human mammary epithelial cell line that expresses SULT1A3 at levels comparable with those found in neurons. The inhibitors perform similarly in ex vivo and in vitro studies; consequently, SULT1A3 turnover can now be potently suppressed in an isoform-specific manner in human cells.

Clinical utility of cricopharyngeal distensibility measurements during endoscopic myotomy for Zenker's diverticulum.

BACKGROUND AND AIMS: Flexible endoscopic cricopharyngeal myotomy (FECM) allows minimally invasive treatment of patients with Zenker's diverticulum (ZD); however, retreatment rates are substantial. We hypothesized that the functional lumen imaging probe (FLIP) may provide insight into ZD pathophysiology and serve as an intraprocedural guide to adequacy of myotomy. METHODS: We prospectively evaluated 11 ZD patients undergoing FECM and compared the baseline cricopharyngeal (CP) distensibility with 16 control subjects. Intraprocedural CP distensibility was measured immediately pre- and postmyotomy. The CP distensibility index (CP-DI) was defined as a ratio of the narrowest cross-sectional area (nCSA) and the corresponding intrabag pressure at 40 mL distension. Same-procedure myotomy extension was undertaken in a subgroup if threshold distensibility changes were not met. RESULTS: ZD patients had reduced baseline nCSA and CP-DI compared with control subjects, (169.6 vs 227.5 mm2 [P < .001] and 3.8 vs 7.6 mm2/mm Hg [P < .001], respectively). After CP myotomy, both nCSA and CP-DI increased significantly by an average of 74.2 mm2 (95% confidence interval [CI], 35.1-113.3; P = .002) and 2.2 mm2/mm Hg (95% CI, .6-3.8; P = .01), respectively. In the subgroup with no significant change in CP distensibility after initial myotomy (n = 6), myotomy extension resulted in significant increases in both mean nCSA and CP-DI of 66.6 mm2 (95% CI, 16.4-116.8; P = .03) and 1.9 mm2/mm Hg (95% CI, .4-3.3; P = .015), respectively. There were no adverse events. CONCLUSIONS: CP distensibility is reduced in ZD patients and is partially reversible by FECM. An intraprocedural FLIP CP distensibility measurement is safe and sensitive in detecting myotomy-induced changes. These findings support using FLIP to optimize FECM outcome. Further studies are required to derive precise metrics predictive of clinical response.

Allosteres to regulate neurotransmitter sulfonation.

Catecholamine neurotransmitter levels in the synapses of the brain shape human disposition-cognitive flexibility, aggression, depression, and reward seeking-and manipulating these levels is a major objective of the pharmaceutical industry. Certain neurotransmitters are extensively sulfonated and inactivated by human sulfotransferase 1A3 (SULT1A3). To our knowledge, sulfonation as a therapeutic means of regulating transmitter activity has not been explored. Here, we describe the discovery of a SULT1A3 allosteric site that can be used to inhibit the enzyme. The structure of the new site is determined using spin-label-triangulation NMR. The site forms a cleft at the edge of a conserved ∼30-residue active-site cap that must open and close during the catalytic cycle. Allosteres anchor into the site via π-stacking interactions with two residues that sandwich the planar core of the allostere and inhibit the enzyme through cap-stabilizing interactions with substituents attached to the core. Changes in cap free energy were calculated ab initio as a function of core substituents and used to design and synthesize a series of inhibitors intended to progressively stabilize the cap and slow turnover. The inhibitors bound tightly (34 nm to 7.4 µm) and exhibited progressive inhibition. The cap-stabilizing effects of the inhibitors were experimentally determined and agreed remarkably well with the theoretical predictions. These studies establish a reliable heuristic for the design of SULT1A3 allosteric inhibitors and demonstrate that the free-energy changes of a small, dynamic loop that is critical for SULT substrate selection and turnover can be calculated accurately.

The Human UGT2B7 Nanodisc.

The 20 uridine diphosphate glycosyl-transferases (UGTs) encoded in the human genome form an essential homeostatic network of overlapping catalytic functions that surveil and regulate the activity and clearance of scores of small molecule metabolites. Biochemical and biophysical UGT studies have been hampered by the inability to purify these membrane-bound proteins. Here, using cell-free expression and nanodisc technology, we assemble and purify to homogeneity the first UGT nanodisc-the human UGT2B7•nanodisc. The complex is readily isolated in milligram quantities. It is stable and its initial-rate parameters are identical within error to those associated with UGT2B7 in microsomal preparations (i.e., Supersomes). The high purity of the nanodisc preparation simplifies UGT assays, which allows complexities traditionally associated with microsomal assays (latency and the albumin effect) to be circumvented. Each nanodisc is shown to harbor a single UGT2B7 monomer. The methods described herein should be widely applicable to UGTs, and these findings are expected to set the stage for experimentalists to more freely explore the structure, function, and biology of this important area of phase II metabolism. SIGNIFICANCE STATEMENT: Lack of access to pure, catalytically competent human uridine diphosphate glucuronosyl-transferases (UGTs) has long been an impediment to biochemical and biophysical studies of this disease-relevant enzyme family. Here, we demonstrate this barrier can be removed using nanodisc technology-a human UGT2B7•nanodisc is assembled, purified to homogeneity, and shown to have activity comparable to microsomal UGT2B7.

Changes in Functional Connectivity Predict Outcome of Repetitive Transcranial Magnetic Stimulation Treatment of Major Depressive Disorder.

Repetitive transcranial magnetic stimulation (rTMS) treatment of major depressive disorder (MDD) is associated with changes in brain functional connectivity (FC). These changes may be related to the mechanism of action of rTMS and explain the variability in clinical outcome. We examined changes in electroencephalographic FC during the first rTMS treatment in 109 subjects treated with 10 Hz stimulation to left dorsolateral prefrontal cortex. All subjects subsequently received 30 treatments and clinical response was defined as ≥40% improvement in the inventory of depressive symptomatology-30 SR score at treatment 30. Connectivity change was assessed with coherence, envelope correlation, and a novel measure, alpha spectral correlation (αSC). Machine learning was used to develop predictive models of outcome for each connectivity measure, which were compared with prediction based upon early clinical improvement. Significant connectivity changes were associated with clinical outcome (P < 0.001). Machine learning models based on αSC yielded the most accurate prediction (area under the curve, AUC = 0.83), and performance improved when combined with early clinical improvement measures (AUC = 0.91). The initial rTMS treatment session produced robust changes in FC, which were significant predictors of clinical outcome of a full course of treatment for MDD.

Tetrahydrobiopterin regulates monoamine neurotransmitter sulfonation.

Monoamine neurotransmitters are among the hundreds of signaling small molecules whose target interactions are switched "on" and "off" via transfer of the sulfuryl-moiety (-SO3) from PAPS (3'-phosphoadenosine 5'-phosphosulfate) to the hydroxyls and amines of their scaffolds. These transfer reactions are catalyzed by a small family of broad-specificity enzymes-the human cytosolic sulfotransferases (SULTs). The first structure of a SULT allosteric-binding site (that of SULT1A1) has recently come to light. The site is conserved among SULT1 family members and is promiscuous-it binds catechins, a naturally occurring family of flavanols. Here, the catechin-binding site of SULT1A3, which sulfonates monoamine neurotransmitters, is modeled on that of 1A1 and used to screen in silico for endogenous metabolite 1A3 allosteres. Screening predicted a single high-affinity allostere, tetrahydrobiopterin (THB), an essential cofactor in monoamine neurotransmitter biosynthesis. THB is shown to bind and inhibit SULT1A3 with high affinity, 23 (±2) nM, and to bind weakly, if at all, to the four other major SULTs found in brain and liver. The structure of the THB-bound binding site is determined and confirms that THB binds the catechin site. A structural comparison of SULT1A3 with SULT1A1 (its immediate evolutionary progenitor) reveals how SULT1A3 acquired high affinity for THB and that the majority of residue changes needed to transform 1A1 into 1A3 are clustered at the allosteric and active sites. Finally, sequence records reveal that the coevolution of these sites played an essential role in the evolution of simian neurotransmitter metabolism.

Dorsolateral prefrontal γ-aminobutyric acid in patients with treatment-resistant depression after transcranial magnetic stimulation measured with magnetic resonance spectroscopy

Background: The therapeutic mechanism of repetitive transcranial magnetic stimulation (rTMS) for treatment-resistant depression (TRD) may involve modulation of γ-aminobutyric acid (GABA) levels. We used proton magnetic resonance spectroscopy (MRS) to assess changes in GABA levels at the site of rTMS in the left dorsolateral prefrontal cortex (DLPFC). Methods: In 26 adults with TRD, we used Mescher­Garwood point-resolved spectroscopy (MEGA-PRESS) spectral-editing MRS to measure GABA in the left DLPFC before and after standard clinical treatment with rTMS. All participants but 1 were medicated, including 12 patients on GABA agonist agents. Results: Mean GABA in the DLPFC increased 10.0% (p = 0.017) post-rTMS in the overall sample. As well, GABA increased significantly in rTMS responders (n = 12; 23.6%, p = 0.015) but not in nonresponders (n = 14; 4.1%, p = not significant). Changes in GABA were not significantly affected by GABAergic agonists, but clinical response was less frequent (p = 0.005) and weaker (p = 0.035) in the 12 participants who were receiving GABA agonists concomitant with rTMS treatment. Limitations: This study had an open-label design in a population receiving naturalistic treatment. Conclusion: Treatment using rTMS was associated with increases in GABA levels at the stimulation site in the left DLPFC, and the degree of GABA change was related to clinical improvement. Participants receiving concomitant treatment with a GABA agonist were less likely to respond to rTMS. These findings were consistent with earlier studies showing the effects of rTMS on GABA levels and support a GABAergic model of depression.

Predictors of response to synchronized transcranial magnetic stimulation for major depressive disorder.

BACKGROUND: Synchronized transcranial magnetic stimulation (sTMS) is a new modality to reduce symptoms of major depressive disorder (MDD). sTMS uses rotating neodymium magnets to deliver low-field stimulation matched to the individual alpha frequency (IAF). A previous multisite study showed that sTMS significantly reduced MDD symptoms in the per-protocol sample. To this end, we evaluated clinical features associated with optimal sTMS outcomes. METHODS: Using the per-protocol sample (n = 120) from the parent sham-controlled trial, we performed univariate and stepwise linear regression to identify predictors of response after 6 weeks of sTMS. A subsample (n = 83) that entered a 4-week open/active continuation phase also was examined. Candidate variables included age, sex, comorbid anxiety, number of failed antidepressants in the current depressive episode, MDD severity (17-item Hamilton Depression Rating Scale; HAMD17), anxiety symptom severity (HAMD17 anxiety/somatization factor), and IAF. RESULTS: We found that greater baseline depressive (p < 0.001) and anxiety (p < 0.001) symptom severity were associated with better response to active sTMS, whereas fewer failed antidepressant trials predicted superior response to sham (p < 0.001). MDD severity and antidepressant resistance predicted outcomes in open/active phase sTMS; lower IAF predicted poorer response in participants who received 10 weeks of active sTMS (p = 0.001). CONCLUSIONS: Participants with greater severity of depression and higher anxiety had superior responses to active sTMS, whereas treatment naïve individuals exhibited a greater response to sham. These results lend support to the primary efficacy findings, and support further investigation of sTMS as a therapeutic noninvasive brain stimulation modality.

The structure of the catechin-binding site of human sulfotransferase 1A1.

We are just beginning to understand the allosteric regulation of the human cytosolic sulfotransferase (SULTs) family-13 disease-relevant enzymes that regulate the activities of hundreds, if not thousands, of signaling small molecules. SULT1A1, the predominant isoform in adult liver, harbors two noninteracting allosteric sites, each of which binds a different molecular family: the catechins (naturally occurring flavonols) and nonsteroidal antiinflammatory drugs (NSAIDs). Here, we present the structure of an SULT allosteric binding site-the catechin-binding site of SULT1A1 bound to epigallocatechin gallate (EGCG). The allosteric pocket resides in a dynamic region of the protein that enables EGCG to control opening and closure of the enzyme's active-site cap. Furthermore, the structure offers a molecular explanation for the isozyme specificity of EGCG, which is corroborated experimentally. The binding-site structure was obtained without X-ray crystallography or multidimensional NMR. Instead, a SULT1A1 apoprotein structure was used to guide positioning of a small number of spin-labeled single-Cys mutants that coat the entire enzyme surface with a paramagnetic field of sufficient strength to determine its contribution to the bound ligand's transverse (T2) relaxation from its 1D solution spectrum. EGCG protons were mapped to the protein surface by triangulation using the T2 values to calculate their distances to a trio of spin-labeled Cys mutants. The final structure was obtained using distance-constrained molecular dynamics docking. This approach, which is readily extensible to other systems, is applicable over a wide range of ligand affinities, requires little protein, avoids the need for isotopically labeled protein, and has no protein molecular weight limitations.

Benefits and Harms of Cranial Electrical Stimulation for Chronic Painful Conditions, Depression, Anxiety, and Insomnia: A Systematic Review.

Background: Cranial electrical stimulation (CES) is increasingly popular as a treatment, yet its clinical benefit is unclear. Purpose: To review evidence about the benefits and harms of CES for adult patients with chronic painful conditions, depression, anxiety, and insomnia. Data Sources: Several databases from inception to 10 October 2017 without language restrictions and references from experts, prior reviews, and manufacturers. Study Selection: Randomized controlled trials of CES versus usual care or sham CES that reported pain, depression, anxiety, or sleep outcomes in any language. Data Extraction: Single-reviewer extraction checked by another; dual independent quality assessment; strength-of-evidence grading by the first author with subsequent group discussion. Data Synthesis: Twenty-eight articles from 26 randomized trials met eligibility criteria. The 2 trials that compared CES with usual care were small, and neither reported a statistically significant benefit in pain or anxiety outcomes for patients with fibromyalgia or anxiety, respectively. Fourteen trials with sham or placebo controls involving patients with painful conditions, such as headache, neuromuscular pain, or musculoskeletal pain, had conflicting results. Four trials done more than 40 years ago and 1 from 2014 provided low-strength evidence of a possible modest benefit compared with sham treatments in patients with anxiety and depression. Trials in patients with insomnia (n = 2), insomnia and anxiety (n = 1), or depression (n = 3) had inconclusive or conflicting results. Low-strength evidence suggested that CES does not cause serious side effects. Limitation: Most trials had small sample sizes and short durations; all had high risk of bias due to inadequate blinding. Conclusion: Evidence is insufficient that CES has clinically important effects on fibromyalgia, headache, neuromusculoskeletal pain, degenerative joint pain, depression, or insomnia; low-strength evidence suggests modest benefit in patients with anxiety and depression. Primary Funding Source: Veterans Affairs Quality Enhancement Research Initiative. (PROSPERO: CRD42016023951).

Brain Activity and Clinical Outcomes in Adults With Depression Treated With Synchronized Transcranial Magnetic Stimulation: An Exploratory Study.

BACKGROUND: Synchronized transcranial magnetic stimulation (sTMS) imparts low-amplitude magnetic stimulation matched to each patient's individual alpha frequency. It may act through entrainment of brain oscillations. OBJECTIVES: To explore sTMS effects on neurophysiology with electroencephalography (EEG) in adults with major depressive disorder. METHODS: As an ancillary study to a clinical trial of sTMS, EEGs were recorded at baseline and at one and six weeks of treatment. Associations between EEG measures and clinical symptoms were examined. RESULTS: Absolute and relative power measures did not differ significantly between active and sham groups and did not change significantly over time. Changes occurring over six weeks in alpha current source density at anterior and central midline voxels were significantly correlated with changes in symptoms in subjects treated with active but not sham sTMS. CONCLUSION: Neurophysiologic measures suggest that active but not sham sTMS engages brain targets, and that target engagement is related to treatment outcome.