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Pain is the most common reason for physician consultations and the number one reason for missed work or school days is musculoskeletal pain. Pain management is utilized for easing the suffering and improving the Quality of Life of those living with chronic pain. Over the past several decades, physicians have become increasingly willing to prescribe opioids to manage pain. However, the opioid use can cause side effects as poor coordination, sedation, mood swings, depression, and anxiety combined with a dependence on the drugs. In the rehabilitation setting, patients benefit most when their health providers utilize a multimodal approach combining different types of therapies and when patients take on a significant role in optimal management of their own pain. The use of light as a therapeutic alternative form of medicine to manage pain and inflammation has been proposed to fill this void. Photobiomodulation therapy applied in the form of low-intensity Light Amplification by Stimulated Emission of Radiation (LASER) and light-emitting diode (LED) has been shown to reduce inflammation and swelling, promote healing, and reduce pain for an array of musculoskeletal conditions. There is evidence that photobiomodulation therapy reduces pain intensity in non-specific knee pain, osteoarthritis, pain post-total hip arthroplasty, fibromyalgia, temporomandibular diseases, neck pain, and low back pain. Therefore, the purpose of this paper was to present the up-to-dated evidence about the effects of low-intensity LASER and LED (photobiomodulation therapy) on pain control of the most common musculoskeletal conditions. We observed that the photobiomodulation therapy offers a non-invasive, safe, drug-free, and side-effect-free method for pain relief of both acute and chronic musculoskeletal conditions as well as fibromyalgia.

Older patients comprise the fastest growing population initiating dialysis. Many have coexisting conditions that affect their experience and survival. These patients spend their last days undergoing intensive therapies at a higher rate than with other life-limiting conditions. The majority of

Conformationally strained trans-cyclooctenes (TCOs) engage in bioorthogonal reactions with tetrazines with second order rate constants that can exceed 106 M-1s-1. The goal of this study was to provide insight into the stability of TCO reagents and to develop methods for stabilizing TCO reagents for long-term storage. The radical inhibitor Trolox suppresses TCO isomerization under high thiol concentrations and TCO shelf-life can be greatly extended by protecting them as stable Ag(I) metal complexes. 1H NMR studies show that Ag-complexation is thermodynamically favorable but the kinetics of dissociation are very rapid, and TCO•AgNO3 complexes are immediately dissociated upon addition of NaCl which is present in high concentration in cell media. The AgNO3 complex of a highly reactive s-TCO-TAMRA conjugate was shown to label a protein-tetrazine conjugate in live cells with faster kinetics and similar labeling yield relative to a 'traditional' TCO-TAMRA conjugate.

PF-06651600 was developed as an irreversible inhibitor of JAK3 with selectivity over the other three JAK isoforms. A high level of selectivity toward JAK3 is achieved by the covalent interaction of PF-06651600 with a unique cysteine residue (Cys-909) in the catalytic domain of JAK3, which is replaced by a serine residue in the other JAK isoforms. Importantly, 10 other kinases in the kinome have a cysteine at the equivalent position of Cys-909 in JAK3. Five of those kinases belong to the TEC kinase family including BTK, BMX, ITK, RLK, and TEC and are also inhibited by PF-06651600. Preclinical data demonstrate that inhibition of the cytolytic function of CD8+ T cells and NK cells by PF-06651600 is driven by the inhibition of TEC kinases. On the basis of the underlying pathophysiology of inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease, alopecia areata, and vitiligo, the dual activity of PF-06651600 toward JAK3 and the TEC kinase family may provide a beneficial inhibitory profile for therapeutic intervention.

Conformationally strained trans-cyclooctenes (TCOs) engage in bioorthogonal reactions with tetrazines with second order rate constants that can exceed 10(6) M(−1)s(−1). The goal of this study was to provide insight into the stability of TCO reagents and to develop methods for stabilizing TCO reagents for long-term storage. The radical inhibitor Trolox suppresses TCO isomerization under high thiol concentrations and TCO shelf-life can be greatly extended by protecting them as stable Ag(I) metal complexes. (1)H NMR studies show that Ag-complexation is thermodynamically favorable but the kinetics of dissociation are very rapid, and TCO•AgNO(3) complexes are immediately dissociated upon addition of NaCl which is present in high concentration in cell media. The AgNO(3) complex of a highly reactive s-TCO-TAMRA conjugate was shown to label a protein-tetrazine conjugate in live cells with faster kinetics and similar labeling yield relative to a ‘traditional’ TCO-TAMRA conjugate.

Clinical investigation of the fatty acid amide hydrolase (FAAH) inhibitor BIA 10–2474 resulted in serious adverse neurological events. Structurally unrelated FAAH inhibitors tested in humans have not presented safety concerns, suggesting that BIA 10–2474 has off-target activities. A recent activity-based protein profiling (ABPP) study revealed that BIA 10–2474 and one of its major metabolites inhibit multiple members of the serine hydrolase class to which FAAH belongs. Here, we extend these studies by performing a proteome-wide analysis of covalent targets of BIA 10–2474 metabolites. Using alkynylated probes for click chemistry-ABPP of human cells, we show that des-methylated metabolites of BIA 10–2474 covalently modify the conserved catalytic cysteine in aldehyde dehydrogenases, including ALDH2, which has been implicated in protecting the brain from oxidative stress-related damage. These findings indicate that BIA 10–2474 and its metabolites have the potential to inhibit multiple mechanistically distinct enzyme classes involved in nervous system function.

Novel chemical biology probes linking a serine hydrolase-directed fluorophosphonate warhead and cereblon-binding pomalidomide were assessed for the degradation of serine hydrolases. A quantitative proteomics approach to detect degraded proteins revealed that, despite the engagement of ∼40 serine hydrolases, degradation was achieved for only a single serine hydrolase, lysophospholipase II (LYPLA2).

The leaders of 20th century kidney failure treatment took chances; 21st century leaders of integrated kidney care must do the same. Some risks are clinical, some are organizational, and some are financial. Decent and constructive leadership entails humility. A working practitioner is a better leader. Effective leaders empower their employees and collaborators to lead and encourage them to work together. Integrated kidney care leadership supports exchange of ideas within and among organizations, uninhibited by competitive considerations. ESRD Seamless Care Organizations lead us toward the kidney care of the future; they will be strengthened by expansion to include patients who have advanced kidney disease not yet requiring renal replacement therapy and patients treated by transplant. Adjustment of reimbursement policy to realign incentives will be essential to the long-term success of care coordination. Population health management, with downside risk for participating organizations, is the future of integrated kidney care. Critical goals for integrated kidney care are to delay or avoid dialysis; increase use of home dialysis, transplantation, nondialytic care, and hospice; and to improve end of life care. It's about the patients, stupid.

A photochemical synthesis of AgNO3 complexes of trans-cycloheptene (TCH) and trans-1-sila-4-cycloheptene (Si-TCH) derivatives is described. A low temperature flow photoreactor was designed to enable the synthesis of carbocyclic TCH derivatives due to their thermal sensitivity in the absence of metal coordination. Unlike the free carbocycles, TCH·AgNO3 complexes can be handled at rt and stored for weeks in the freezer (−18 °C). Si-TCH·AgNO3 complexes are especially robust, and are bench stable for days at rt, and for months in the freezer. X-ray crystallography was used to characterize a Si-TCH·AgNO3 complex for the first time. With decomplexation of AgNO3in situ, metal-free TCO and Si-TCH derivatives can engage in a range of cycloaddition reactions as well as dihydroxylation reactions. Computation was used to predict that Si-TCH would engage in bioorthogonal reactions that are more rapid than the most reactive trans-cyclooctenes. Metal-free Si-TCH derivatives were shown to display good stability in solution, and to engage in the fastest bioorthogonal reaction reported to date (k2 1.14 × 107 M−1 s−1 in 9 : 1 H2O : MeOH). Utility in bioorthogonal protein labeling in live cells is described, including labeling of GFP with an unnatural tetrazine-containing amino acid. The reactivity and specificity of the Si-TCH reagents with tetrazines in live mammalian cells was also evaluated using the HaloTag platform. The cell labeling experiments show that Si-TCH derivatives are best suited as probe molecules in the cellular environment.

Patient care in advanced CKD and ESKD is fragmented; it misses many opportunities to improve patient experience of care and population health as well as to reduce cost. Integrated care should treat patients with CKD as individuals with important current clinical needs, not just as people who may

Innate immunity is associated with Alzheimer’s disease1, but the influence of immune activation on the production of amyloid-β is unknown2,3. Here we identify interferon-induced transmembrane protein 3 (IFITM3) as a γ-secretase modulatory protein, and establish a mechanism by which inflammation affects the generation of amyloid-β. Inflammatory cytokines induce the expression of IFITM3 in neurons and astrocytes, which binds to γ-secretase and upregulates its activity, thereby increasing the production of amyloid-β. The expression of IFITM3 is increased with ageing and in mouse models that express familial Alzheimer’s disease genes. Furthermore, knockout of IFITM3 reduces γ-secretase activity and the formation of amyloid plaques in a transgenic mouse model (5xFAD) of early amyloid deposition. IFITM3 protein is upregulated in tissue samples from a subset of patients with late-onset Alzheimer’s disease that exhibit higher γ-secretase activity. The amount of IFITM3 in the γ-secretase complex has a strong and positive correlation with γ-secretase activity in samples from patients with late-onset Alzheimer’s disease. These findings reveal a mechanism in which γ-secretase is modulated by neuroinflammation via IFITM3 and the risk of Alzheimer’s disease is thereby increased. The IFITM3 innate immunity protein directly binds presenilin near the active site and upregulates γ-secretase activity and the production of amyloid-β, and IFITM3 is upregulated in patients with late-onset Alzheimer’s disease.

Rationale & objective During the COVID-19 pandemic, patients receiving maintenance dialysis are a highly vulnerable population due to their comorbidities and circumstances that limit physical distancing during treatment. This study sought to characterize the risk factors for and outcomes following COVID-19 infection in this population. Study design Retrospective cohort study. Setting & participants Maintenance dialysis patients in clinics with at least one patient with a positive test for SARS-CoV-2 from February to June 2020, treated by a mid-size national dialysis provider. Predictors Demographics, dialysis characteristics, residence in a congregate setting, comorbid conditions, measures of frailty, and use of selected medications. Outcomes COVID-19 defined as having a positive SARS-CoV-2 test and all-cause mortality among those with COVID-19. Analytical approach Logistic regression analyses to identify clinical characteristics associated with COVID-19and risk factors associated with mortality among patients following COVID-19. Results 438/7948 (5.5%) maintenance dialysis patients developed COVID-19. Male sex, Black race, in-center dialysis (vs. home dialysis), treatment at an urban clinic, residence in a congregate setting, and greater comorbidity were associated with contracting COVID-19. Odds of COVID-19 was 17-fold higher for those residing in a congregate setting [OR = 17.10 (95% CI 13.51, 21.54)]. Of the 438 maintenance dialysis patients with COVID-19, 109 (24.9%) died. Older age, heart disease, and markers of frailty were associated with mortality. Limitations No distinction between symptomatic and asymptomatic SARS-CoV-2 positivity, with asymptomatic screening limited by testing capacity during this initial COVID-19 surge period. Conclusions COVID-19 is common among patients receiving maintenance dialysis, particularly those residing in congregate settings. Among maintenance dialysis patients with COVID-19, mortality is high, exceeding 20%.

Summary Utilizing a phenotypic screen, we identified chemical matter that increased astrocytic apoE secretion in vitro. We designed a clickable photoaffinity probe based on a pyrrolidine lead compound and carried out probe-based quantitative chemical proteomics in human astrocytoma CCF-STTG1 cells to identify liver x receptor β (LXRβ) as the target. Binding of the small molecule ligand stabilized LXRβ, as shown by cellular thermal shift assay (CETSA). In addition, we identified a probe-modified peptide by mass spectrometry and proposed a model where the photoaffinity probe is bound in the ligand-binding pocket of LXRβ. Taken together, our findings demonstrated that the lead chemical matter bound directly to LXRβ, and our results highlight the power of chemical proteomic approaches to identify the target of a phenotypic screening hit. Additionally, the LXR photoaffinity probe and lead compound described herein may serve as valuable tools to further evaluate the LXR pathway.

Monoacylglycerol lipase (MAGL) inhibition provides a potential treatment approach to neuroinflammation through modulation of both the endocannabinoid pathway and arachidonoyl signaling in the central nervous system (CNS). Herein we report the discovery of compound 15 (PF-06795071), a potent and selective covalent MAGL inhibitor, featuring a novel trifluoromethyl glycol leaving group that confers significant physicochemical property improvements as compared with earlier inhibitor series with more lipophilic leaving groups. The design strategy focused on identifying an optimized leaving group that delivers MAGL potency, serine hydrolase selectivity, and CNS exposure while simultaneously reducing log D, improving solubility, and minimizing chemical lability. Compound 15 achieves excellent CNS exposure, extended 2-AG elevation effect in vivo, and decreased brain inflammatory markers in response to an inflammatory challenge.

Purpose of review The role of nutrition and nutritional supplementation in dialysis recently has been reinvigorated, with small clinical trials exploring surrogate outcomes and larger epidemiologic studies generating treatment hypotheses requiring further study. The present review focuses on major aspects of nutrition and outcomes in hemodialysis patients: protein and calorie intake and nutritional vitamin D supplementation. Recent findings Building on data from small studies, two large, quasi-experimental cohort studies showed significant mortality benefits associated with oral nutritional supplements provided during dialysis, suggesting potential options for ameliorating the protein-energy wasting that is common in dialysis patients and associated with poor outcomes. Multiple cohort studies suggest, both in the general population and in dialysis, that higher 25(OH) vitamin D levels are associated with improved outcomes; however, no major mortality trials exist in dialysis, and the smaller, surrogate studies conducted to date have been disappointing, showing no consistent benefits in surrogate outcomes including inflammation and anemia, despite appropriate responses of vitamin D levels to repletion. Summary Nutritional interventions are attractive options for improving outcomes in dialysis patients. Nutritional protein supplements have considerable promise, but require further study, preferably in a large, generalizable pragmatic trial. Small nutritional vitamin D supplementation trials in dialysis have had disappointing results. In the absence of new data, there appears to be no role for routine assessment or repletion of 25(OH) vitamin D deficiency or insufficiency in dialysis.

Bioorthogonal reactions, including the strain-promoted azide-alkyne cycloaddition (SPAAC) and inverse electron demand Diels-Alder (iEDDA) reactions, have become increasingly popular for live-cell imaging applications. However, the stability and reactivity of reagents has never been systematically explored in the context of a living cell. Here we report a universal, organelle-targetable system based on HaloTag protein technology for directly comparing bioorthogonal reagent reactivity, specificity, and stability using clickable HaloTag ligands in various subcellular compartments. This system enabled a detailed comparison of the bioorthogonal reactions in live cells and informed the selection of optimal reagents and conditions for live-cell imaging studies. We found that the reaction of sTCO with monosubstituted tetrazines is the fastest reaction in cells; however, both reagents have stability issues. To address this, we introduced a new variant of sTCO, Ag-sTCO, which has much improved stability and can be used directly in cells for rapid bioorthogonal reactions with tetrazines. Utilization of Ag complexes of conformationally strained trans-cyclooctenes should greatly expand their usefulness especially when paired with less reactive, more stable tetrazines.

Infections continue to be a major cause of disease and contributor to death in patients on dialysis. Despite our knowledge and acceptance that hemodialysis catheters should be avoided and eliminated, most patients who begin dialysis initiate treatment through a central vein hemodialysis catheter. Dialysis Medical Directors must be the instrument through which our industry changes. We must lead the charge to educate our dialysis staff and our dialysis patients. We must also educate ourselves so that we not only know that our facility policies are consistent with the best evidence available, but we must also know where local and federal regulations differ. When these differences impact on patient care, we must speak out and have these regulations changed. But it is not enough to know the rules and write them. We must lead by example and show our patients, our nephrology colleagues and our dialysis staff that we always follow these same policies. We need to practice what we preach and be willing and available to redirect those individuals who have difficulty following the rules. In order to effectively change process meaningful data must be collected, analyzed and acted upon. Dialysis Medical Directors must direct and lead the quality improvement process. We hope this review provides Dialysis Medical Directors with the necessary tools to effectively drive this process and improve care.

Herein we describe the design and synthesis of a series of pyridopyrazine-1,6-dione γ-secretase modulators (GSMs) for Alzheimer's disease (AD) that achieve good alignment of potency, metabolic stability, and low MDR efflux ratios, while also maintaining favorable physicochemical properties. Specifically, incorporation of fluorine enabled design of metabolically less liable lipophilic alkyl substituents to increase potency without compromising the sp(3)-character. The lead compound 21 (PF-06442609) displayed a favorable rodent pharmacokinetic profile, and robust reductions of brain Aβ42 and Aβ40 were observed in a guinea pig time-course experiment.

Many natural products that show therapeutic activities are oftentimes difficult to synthesize or isolate and have unknown targets, hindering their development as drugs. Identifying druggable hotspots targeted by covalently-acting anti-cancer natural products can enable pharmacological interrogation of these sites with more synthetically tractable compounds. Here, we used chemoproteomic platforms to discover that the anti-cancer natural product withaferin A targets C377 on the regulatory subunit PPP2R1A of the tumor suppressor protein phosphatase 2A (PP2A) complex leading to activation of PP2A activity, inactivation of AKT, and impaired breast cancer cell proliferation. We developed a more synthetically tractable cysteine-reactive covalent ligand, JNS 1–40, that selectively targets C377 of PPP2R1A to impair breast cancer signaling, proliferation, and in vivo tumor growth. Our study highlights the utility of using chemoproteomics to map druggable hotspots targeted by complex natural products and subsequently interrogating these sites with more synthetically tractable covalent ligands for cancer therapy.

Monoacylglycerol lipase (MAGL) is the main enzyme responsible for degradation of the endocannabinoid 2-arachidonoylglycerol (2-AG) in the CNS. MAGL catalyzes the conversion of 2-AG to arachidonic acid (AA), a precursor to the proinflammatory eicosannoids such as prostaglandins. Herein we describe highly efficient MAGL inhibitors, identified through a parallel medicinal chemistry approach that highlighted the improved efficiency of azetidine and piperidine-derived carbamates. The discovery and optimization of 3-substituted azetidine carbamate irreversible inhibitors of MAGL were aided by the generation of inhibitor-bound MAGL crystal structures. Compound 6, a highly efficient and selective MAGL inhibitor against recombinant enzyme and in a cellular context, was tested in vivo and shown to elevate central 2-AG levels at a 10 mg/kg dose.

Synthesis and transformations of AgNO3 complexes of trans-cycloheptene (TCH) and trans-1-sila-4-cycloheptene (Si-TCH) derivatives are described., A photochemical synthesis of AgNO3 complexes of trans-cycloheptene (TCH) and trans-1-sila-4-cycloheptene (Si-TCH) derivatives is described. A low temperature flow photoreactor was designed to enable the synthesis of carbocyclic TCH derivatives due to their thermal sensitivity in the absence of metal coordination. Unlike the free carbocycles, TCH·AgNO3 complexes can be handled at rt and stored for weeks in the freezer (–18 °C). Si-TCH·AgNO3 complexes are especially robust, and are bench stable for days at rt, and for months in the freezer. X-ray crystallography was used to characterize a Si-TCH·AgNO3 complex for the first time. With decomplexation of AgNO3in situ, metal-free TCO and Si-TCH derivatives can engage in a range of cycloaddition reactions as well as dihydroxylation reactions. Computation was used to predict that Si-TCH would engage in bioorthogonal reactions that are more rapid than the most reactive trans-cyclooctenes. Metal-free Si-TCH derivatives were shown to display good stability in solution, and to engage in the fastest bioorthogonal reaction reported to date (k2 1.14 × 107 M–1 s–1 in 9 : 1 H2O : MeOH). Utility in bioorthogonal protein labeling in live cells is described, including labeling of GFP with an unnatural tetrazine-containing amino acid. The reactivity and specificity of the Si-TCH reagents with tetrazines in live mammalian cells was also evaluated using the HaloTag platform. The cell labeling experiments show that Si-TCH derivatives are best suited as probe molecules in the cellular environment.

Addressing fluid intake and volume control requires alignment and coordination of patients, providers, dialysis facilities, and payers, potentially necessitating a "Volume First" approach. This article reports the consensus opinions achieved at the March 2013 symposium of the Chief Medical Officers of 14 of the largest dialysis providers in the United States. These opinions are based on broad experience among participants, but often reinforced by only observational and frequently retrospective studies, highlighting the lack of high-quality clinical trials in nephrology. Given the high morbidity and mortality rates among dialysis patients and the absence of sufficient trial data to guide most aspects of hemodialysis therapy, participants believed that immediate attempts to improve care based on quality improvement initiatives, physiologic principles, and clinical experiences are warranted until such time as rigorous clinical trial data become available. The following overarching consensus opinions emerged. (1) Extracellular fluid status should be a component of sufficient dialysis, such that approaching normalization of extracellular fluid volume should be a primary goal of dialysis care. (2) Fluid removal should be gradual and dialysis treatment duration should not routinely be less than 4 hours without justification based on individual patient factors. (3) Intradialytic sodium loading should be avoided by incorporating dialysate sodium concentrations set routinely in the range of 134-138 mEq/L, avoidance of routine use of sodium modeling, and avoidance of hypertonic saline solution. (4) Dietary counseling should emphasize sodium avoidance.

Phosphodiesterases (PDEs) regulate the levels of the second messengers cAMP and cGMP and are important drug targets. PDE10A is highly enriched in medium spiny neurons of the striatum and is an attractive drug target for the treatment of basal ganglia diseases like schizophrenia, Parkinson's disease, or Huntington's disease. Here we describe the design, synthesis, and application of a variety of chemical biology probes, based on the first clinically tested PDE10A inhibitor MP-10, which were used to characterize the chemoproteomic profile of the clinical candidate in its native environment. A clickable photoaffinity probe was used to measure target engagement of MP-10 and revealed differences between whole cell and membrane preparations. Moreover, our results illustrate the importance of the linker design in the creation of functional probes. Biotinylated affinity probes allowed identification of drug-interaction partners in rodent and human tissue and quantitative mass spectrometry analysis revealed highly specific binding of MP-10 to PDE10A with virtually no off-target binding. The profiling of PDE10A chemical biology probes described herein illustrates a strategy by which high affinity inhibitors can be converted into probes for determining selectivity and target engagement of drug candidates in complex biological matrices from native sources.

Past advances in research and modern medicine have helped to produce cures for diseases that used to plague populations, and as a result, life expectancies have increased substantially throughout the years. For example, in East Asia, the average life expectancy has nearly doubled within the last sixty-four years (from 45 years old in 1950 to over 74 years old today). Such statistics often give promise and meaning to the medicinal opportunities offered through scientific research; however, the successes also present new challenges. Neurodegenerative diseases, often developed in the later stages of life, have become increasingly more prevalent, no doubt a direct result of increased longevity, as well as a serious medical and economical challenge to today’s society. For example, The World Health Organization projects that neurodegenerative diseases will surpass cancer to become the second leading cause of death by 2040. Therefore, the urgency to understand the fundamentals of neurodegenerative diseases as well as develop diagnostic and therapeutic agents is apparent. In this themed issue of Chemical Society Reviews on molecular medicine and neurodegenerative diseases, several areas within the neurodegenerative field are explored, including mechanistic/ structural studies of neurodegenerative processes, pathologically relevant biological pathways/factors, as well as the development of chemical tools, diagnostic/ imaging agents, and potential therapeutic agents. By no means is this themed issue comprehensive on neurodegenerative diseases, but researchers new to the field, as well as others actively engaged in this field, will find broad insights into the multifactorial components of Alzheimer’s disease (AD). Our hope is that the highlighted works from prominent scientists would stimulate scientists to target their current and future research toward answering some of the critical questions within the field that will be essential to uncovering the pathology of the disease so that possible treatments or therapeutics can be developed. Neurodegenerative diseases are inherently complex and the disease etiology is not completely understood. Hallmarks of diseases have been identified, such as aggregated misfolded proteins (e.g., amyloid-b, Ab; tau) in AD, yet the roles of these pathological features in disease onset and progression are still unclear. To develop an effective therapeutic, the fundamentals of the disease, such as the correlation of misfolded peptides to neuropathogenesis, need to first be fully revealed. In the review of ‘‘Disordered amyloidogenic peptides may insert into the membrane and assemble into common cyclic structural motifs’’, Jang, Arce, Ramachandran, Kaga, Lal, and Nussinov (DOI: 10.1039/c3cs60459d) provide an overview of the interaction of Ab with cell membranes contributing to cellular dysfunction. From this review, the readers will gain insights into aspects of the disease, such as a proposed mechanism of Ab toxicity, through various conformational structures, particularly oligomers, of the Ab peptide that could form amyloid channels within the membrane, ultimately leading to the loss of ionic homeostasis within the cell that directs cell death. Moreover, Kotler, Walsh, Brender, and Ramamoorthy (DOI: 10.1039/ c3cs60431d) offer an additional view on the interrelationship between Ab peptides and cellular membranes as a potential underlying cause of toxicity. More interestingly, the authors present further perspective on the influence of gangliosides, molecules composed of a glycosphingolipid with one or more sialic a Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA. E-mail: chrischang@berkeley.edu b Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA c Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720, USA d Department of Chemical Physiology, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA. E-mail: cravatt@scripps.edu e Pfizer Worldwide Research and Development, Cambridge, MA 02139, USA. E-mail: Doug.Johnson@pfizer.com f Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea. E-mail: mhlim@unist.ac.kr g Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA DOI: 10.1039/c4cs90065k

The Centers for Medicare and Medicaid Services oversees the ESRD Quality Incentive Program to ensure that the highest quality of health care is provided by outpatient dialysis facilities that treat patients with ESRD. To that end, Centers for Medicare and Medicaid Services uses clinical performance measures to evaluate quality of care under a pay-for-performance or value-based purchasing model. Now more than ever, the ESRD therapeutic area serves as the vanguard of health care delivery. By translating medical evidence into clinical performance measures, the ESRD Prospective Payment System became the first disease-specific sector using the pay-for-performance model. A major challenge for the creation and implementation of clinical performance measures is the adjustments that are necessary to transition from taking care of individual patients to managing the care of patient populations. The National Quality Forum and others have developed effective and appropriate population-based clinical performance measures quality metrics that can be aggregated at the physician, hospital, dialysis facility, nursing home, or surgery center level. Clinical performance measures considered for endorsement by the National Quality Forum are evaluated using five key criteria: evidence, performance gap, and priority (impact); reliability; validity; feasibility; and usability and use. We have developed a checklist of special considerations for clinical performance measure development according to these National Quality Forum criteria. Although the checklist is focused on ESRD, it could also have broad application to chronic disease states, where health care delivery organizations seek to enhance quality, safety, and efficiency of their services. Clinical performance measures are likely to become the norm for tracking performance for health care insurers. Thus, it is critical that the methodologies used to develop such metrics serve the payer and the provider and most importantly, reflect what represents the best care to improve patient outcomes.

Background Hemodialysis patients have high mortality rates, potentially reflecting underlying comorbid conditions and ongoing catabolism. Intradialytic oral nutritional supplements may reduce this risk. Study Design Retrospective propensity-matched cohort. Setting & Participants Maintenance hemodialysis patients treated at Dialysis Clinic Inc facilities who were initiated on a nutritional supplement protocol in September to October 2010 were matched using a propensity score to patients at facilities at which the protocol was not used. Predictors Prescription of the protocol, whereby hemodialysis patients with serum albumin levels ≤3.5g/dL would initiate oral protein supplementation during the dialysis procedure. Sensitivity analyses matched on actual supplement intake during the first 3 study months. Covariates included patient and facility characteristics, which were used to develop the propensity scores and adjust multivariable models. Outcomes All-cause mortality, ascertained though March 2012. Results Of 6,453 eligible patients in 101 eligible hemodialysis facilities, the protocol was prescribed to 2,700, and 1,278 of these were propensity matched to controls. Mean age was 61 ± 15 (SD) years and median dialysis vintage was 34 months. There were 258 deaths among protocol assignees versus 310 among matched controls during a mean follow-up of 14 months. In matched analyses, protocol prescription was associated with a 29% reduction in the hazard of all-cause mortality (HR, 0.71; 95% CI, 0.58-0.86); adjustment had minimal impact on models. In time-dependent models incorporating change in albumin level, protocol status remained significant but was attenuated in models incorporating a 30-day lag. Similar results were seen in sensitivity analyses of 439 patients receiving supplements who were propensity-matched to controls, with 116 deaths among supplement users versus 140 among controls (HR, 0.79; 95% CI, 0.60-1.05), achieving statistical significance in adjusted models. Limitations Observational design, potential residual confounding. Conclusions Prescription of an oral nutritional supplement protocol and use of oral protein nutritional supplements during hemodialysis are associated with reduced mortality among in-center maintenance hemodialysis patients, an effect likely not mediated by change in serum albumin levels.

Glyoxalase I (GLO-1) plays a critical role in the detoxification of 2-oxoaldehydes and is highly expressed in cancer cells. Through photo-affinity labelling and affinity pull-down approaches, a series of 2,4-diaminopyrimidine compounds were discovered to selectively bind to GLO-1 in cells. These compounds show potent inhibition of GLO-1 enzyme activity and prevent proliferation of cancer cells. The cell permeable and “clickable” photoaffinity probe L1-Bpyne presented here could be a valuable tool for profiling GLO-1 in live cells.

γ-Secretase undergoes endoproteolysis of its catalytic subunit, presenilin (PS), to form PS N-terminal and C-terminal fragments (PS1-NTF/CTF), which generate the active site. PS endoproteolysis, catalyzed by presenilinase (PSase), remains poorly understood and requires novel chemical approaches for its mechanistic study. CBAP is a dual inhibitor that suppresses both γ-secretase and PSase activities. To probe γ-secretase and PSase activity in cells, we have synthesized the clickable photoaffinity probe CBAP-BPyne. We found that CBAP-BPyne specifically labels PS1-NTF and signal peptide peptidase (SPP). CBAP-BPyne is a valuable tool to directly study the mechanism of endoproteolysis.

We have developed a suite of clickable γ-secretase active site-directed dual-photoaffinity probes possessing photoactivatable benzophenones that are located within the inhibitor scaffold as well as spaced away from the core by a linker. Through photoactivation of these dual photoprobes and subsequent click chemistry mediated conjugation of a reporter group, we have been able to specifically label PS1-N-terminal fragment (PS1-NTF), PS1-C-terminal fragment (PS1-CTF) and nicastrin and form a pseudo-full length PS1 through crosslinks between PS1-NTF and PS1-CTF. Probe-mediated protein–protein crosslinks were confirmed by in-gel fluorescence, western blotting and LC-MS/MS detection of tryptic peptides of the electrophoretically separated proteins.

γ-Secretase is the enzyme responsible for the final step of amyloid precursor protein proteolysis to generate Aβ peptides including Aβ42 which is believed to be a toxic species involved in Alzheimer's disease (AD) progression. γ-Secretase modulators (GSMs) have been shown to selectively lower Aβ42 production without affecting total Aβ levels or the formation of γ-secretase substrate intracellular domains such as APP intracellular domain and Notch intracellular domain. Therefore, GSMs have emerged as an important therapeutic strategy for the treatment of AD.The literature covering novel GSMs will be reviewed focusing on patents from 2010 to 2012.During the last review period (2008 - 2010) considerable progress was made developing GSMs with improved potency for lowering Aβ42 levels, but most of the compounds resided in unfavorable central nervous system (CNS) drug space. In this review period (2010 - 2012), there is a higher percentage of potent GSM chemical matter that resides in favorable CNS drug space. It is anticipated that clinical candidates will emerge out of this cohort that will be able to test the GSM mechanism of action in the clinic.

Putting a number on it: Cleavable linkers are widely utilized in proteomics applications. In particular, the azobenzene-based linker cleaves under mild conditions that are mass-spectrometry-compatible. Here, we adapt this linker for quantitative proteomic applications by incorporating an isotopic label. These light- and heavy-tagged linkers enable the identification and quantitation of labeled peptides from multiple proteomes.

γ-Secretase is an aspartyl intramembranal protease composed of presenilin, Nicastrin, Aph1, and Pen2 with 19 transmembrane domains. γ-Secretase cleaves the amyloid precursor proteins (APP) to release Aβ peptides that likely play a causative role in the pathogenesis of Alzheimer's disease (AD). In addition, γ-secretase cleaves Notch and other type I membrane proteins. γ-Secretase inhibitors (GSIs) have been developed and used for clinical studies. However, clinical trials have shown adverse effects of GSIs that are potentially linked with nondiscriminatory inhibition of Notch signaling, overall APP processing, and other substrate cleavages. Therefore, these findings call for the development of disease-modifying agents that target γ-secretase activity to lower levels of Aβ42 production without blocking the overall processing of γ-secretase substrates. γ-Secretase modulators (GSMs) originally derived from nonsteroidal anti-inflammatory drugs (NSAIDs) display such characteristics and are the focus of this review. However, first-generation GSMs have limited potential because of the low potency and undesired neuropharmacokinetic properties. This generation of GSMs has been suggested to interact with the APP substrate, γ-secretase, or both. To improve the potency and brain availability, second-generation GSMs, including NSAID-derived carboxylic acid and non-NSAID-derived heterocyclic chemotypes, as well as natural product-derived GSMs have been developed. Animal studies of this generation of GSMs have shown encouraging preclinical profiles. Moreover, using potent GSM photoaffinity probes, multiple studies unambiguously have showed that both carboxylic acid and heterocyclic GSMs specifically target presenilin, the catalytic subunit of γ-secretase. In addition, two types of GSMs have distinct binding sites within the γ-secretase complex and exhibit different Aβ profiles. GSMs induce a conformational change of γ-secretase to achieve modulation. Various models are proposed and discussed. Despite the progress of GSM research, many outstanding issues remain to be investigated to achieve the ultimate goal of developing GSMs as effective AD therapies.

γ-Secretase is an intramembrane aspartyl protease that cleaves the amyloid precursor protein to produce neurotoxic β-amyloid peptides (i.e. Aβ42) that have been implicated in the pathogenesis of Alzheimer disease. Small molecule γ-secretase modulators (GSMs) have emerged as potential disease-modifying treatments for Alzheimer disease because they reduce the formation of Aβ42 while not blocking the processing of γ-secretase substrates. We developed clickable GSM photoaffinity probes with the goal of identifying the target of various classes of GSMs and to better understand their mechanism of action. Here, we demonstrate that the photoaffinity probe E2012-BPyne specifically labels the N-terminal fragment of presenilin-1 (PS1-NTF) in cell membranes as well as in live cells and primary neuronal cultures. The labeling is competed in the presence of the parent imidazole GSM E2012, but not with acid GSM-1, allosteric GSI BMS-708163, or substrate docking site peptide inhibitor pep11, providing evidence that these compounds have distinct binding sites. Surprisingly, we found that the cross-linking of E2012-BPyne to PS1-NTF is significantly enhanced in the presence of the active site-directed GSI L-685,458 (L458). In contrast, L458 does not affect the labeling of the acid GSM photoprobe GSM-5. We also observed that E2012-BPyne specifically labels PS1-NTF (active γ-secretase) but not full-length PS1 (inactive γ-secretase) in ANP.24 cells. Taken together, our results support the hypothesis that multiple binding sites within the γ-secretase complex exist, each of which may contribute to different modes of modulatory action. Furthermore, the enhancement of PS1-NTF labeling by E2012-BPyne in the presence of L458 suggests a degree of cooperativity between the active site of γ-secretase and the modulatory binding site of certain GSMs.

γ-Secretase, a four-subunit transmembrane aspartic proteinase, is a highly valued drug target in Alzheimer's disease and cancer. Despite significant progress in structural studies, the respective molecular mechanisms and binding modes of γ-secretase inhibitors (GSIs) and modulators (GSMs) remain uncertain. Here, we developed biotinylated cleavable-linker photoprobes based on the BMS-708163 GSI to study its interaction with γ-secretase. Comparison of four cleavable linkers indicated that the hydrazine-labile N-1-(4,4-dimethyl-2,6-dioxocyclohexylidene)ethyl (Dde) linker was cleaved most efficiently to release photolabeled and affinity-captured presenilin-1 (PS1), the catalytic subunit of γ-secretase. Peptide mapping showed that the BMS-708163-based probe photoinserted at L282 of PS1. This insertion site was consistent with the results of molecular dynamics simulations of the γ-secretase complex with inhibitor. Taken together, this work reveals the binding site of a GSI and offers insights into the mechanism of action of this class of inhibitors.

γ-Secretase is an intramembrane aspartyl protease comprised of four essential subunits including presenilin, nicastrin (NCT), anterior pharynx defective 1 (Aph-1), and presenilin enhancer 2 (Pen-2). The amyloid precursor protein (APP) is cleaved sequentially by β-secretase and γ-secretase to generate Aβ peptides including neurotoxic Aβ42 monomers and oligomers that are believed to be key pathological species in AD. Familial Alzheimer’s disease (FAD) mutations in presenilin and APP increase the relative proportion of Aβ42. γ-Secretase modulators (GSMs) have been discovered that bind to presenilin and selectively modulate γ-secretase proteolytic activity. Importantly, GSMs have the opposite effect on the Aβ cleavage profile as compared to FAD mutations, namely they decrease the relative proportion of Aβ42. This review will discuss the initial discovery of GSMs and the recent progress leading to the development of GSMs with improved drug-likeness. These efforts have culminated in GSMs that are currently undergoing proof-of-mechanism studies in the clinic, which is a significant step forward toward testing the amyloid hypothesis.

Herein we describe the discovery of a novel series of cyclopropyl chromane-derived pyridopyrazine-1,6-dione γ-secretase modulators for the treatment of Alzheimer's disease (AD). Using ligand-based design tactics such as conformational analysis and molecular modeling, a cyclopropyl chromane unit was identified as a suitable heterocyclic replacement for a naphthyl moiety that was present in the preliminary lead 4. The optimized lead molecule 44 achieved good central exposure resulting in robust and sustained reduction of brain amyloid-β42 (Aβ42) when dosed orally at 10 mg kg−1 in a rat time-course study. Application of the unpaced isolated heart Langendorff model enabled efficient differentiation of compounds with respect to cardiovascular safety, highlighting how minor structural changes can greatly impact the safety profile within a series of compounds.

Fatty acid amide hydrolase (FAAH) is responsible for the enzymatic degradation of the fatty acid amide family of signaling lipids, including the endogenous cannabinoid (endocannabinoid) anandamide. The involvement of the endocannabinoid system in pain and other nervous system disorders has made FAAH an attractive target for drug development. Companion molecular imaging probes are needed, however, to assess FAAH inhibition in the nervous system in vivo. We report here the synthesis and in vivo evaluation of [(18)F]PF-9811, a novel PET ligand for non-invasive imaging of FAAH in the brain.The potency and selectivity of unlabeled PF-9811 were determined by activity-based protein profiling (ABPP) both in vitro and in vivo. [(18)F]PF-9811 was synthesized in a 3-step, one-pot reaction sequence, followed by HPLC purification. Biological evaluation was performed by biodistribution and dynamic PET imaging studies in male rats. The specificity of [(18)F]PF-9811 uptake was evaluated by pre-administration of PF-04457845, a potent and selective FAAH inhibitor, 1h prior to radiotracer injection.Biodistribution studies show good uptake (SUV~0.8 at 90 min) of [(18)F]PF-9811 in rat brain, with significant reduction of the radiotracer in all brain regions (37%-73% at 90 min) in blocking experiments. Dynamic PET imaging experiments in rat confirmed the heterogeneous uptake of [(18)F]PF-9811 in brain regions with high FAAH enzymatic activity, as well as statistically significant reductions in signal following pre-administration of the blocking compound PF-04457845.[(18)F]PF-9811 is a promising PET imaging agent for FAAH. Biodistribution and PET imaging experiments show that the tracer has good uptake in brain, regional heterogeneity, and specific binding as determined by blocking experiments with the highly potent and selective FAAH inhibitor, PF-04457845.

We report the discovery and optimization of a novel series of dihydrobenzofuran amides as γ-secretase modulators (GSMs). Strategies for aligning in vitro potency with drug-like physicochemical properties and good microsomal stability while avoiding P-gp mediated efflux are discussed. Lead compounds such as 35 and 43 have moderate to good in vitro potency and excellent selectivity against Notch. Good oral bioavailability was achieved as well as robust brain Aβ42 lowering activity at 100 mg/kg po dose.

γ-Secretase is involved in the final processing of the amyloid precursor protein into a heterogeneous pool of β-amyloid (Aβ) peptides. Current Alzheimer’s disease drug discovery efforts include targeting γ-secretase activity in brain to attenuate production of the neurotoxic Aβ species. The resulting pharmacology may be affected by species-specific differences in the γ-secretase core complex or its associated proteins. Therefore, we utilized partially purified γ-secretase membranes derived from the brains of different species, including human cortex, to quantitatively assess the de novo production of both Aβ42 and Aβ40 following treatment with known γ-secretase inhibitors and modulators. We determined that the inhibitory activity of a Notch-1 sparing γ-secretase inhibitor and the modulatory activity of two classes of γ-secretase modulators were equipotent at affecting the production of Aβ across rodent and human brain membrane preparations. Additionally, the observed modulator-specific Aβ profile in isolated brain membranes across species was similar to that observed in HeLa cell membranes, and the brain and CSF of guinea pigs following oral administration. By utilizing rapidly purified γ-secretase, we were able to probe and compare the complex pharmacology of γ-secretase in the brain across common rodent species and human cortex.

The pharmaceutical industry is facing numerous, well-documented challenges – from the effects of patent expirations to high attrition rates in the drug-development pipeline. Future Medicinal Chemistry has invited a group of leaders from academia and industry to express their views on where the industry is heading and speculate as to what role medicinal chemists will play in the future.

The two major endocannabinoid transmitters, anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are degraded by distinct enzymes in the nervous system, fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL), respectively. FAAH and MAGL inhibitors cause elevations in brain AEA and 2-AG levels, respectively, and reduce pain, anxiety, and depression in rodents without causing the full spectrum of psychotropic behavioral effects observed with direct cannabinoid receptor-1 (CB1) agonists. These findings have inspired the development of several classes of endocannabinoid hydrolase inhibitors, most of which have been optimized to show specificity for either FAAH or MAGL or, in certain cases, equipotent activity for both enzymes. Here, we investigate an unusual class of O-hydroxyacetamide carbamate inhibitors and find that individual compounds from this class can serve as selective FAAH or dual FAAH/MAGL inhibitors in vivo across a dose range (0.125-12.5 mg kg(-1)) suitable for behavioral studies. Competitive and click chemistry activity-based protein profiling confirmed that the O-hydroxyacetamide carbamate SA-57 is remarkably selective for FAAH and MAGL in vivo, targeting only one other enzyme in brain, the additional 2-AG hydrolase ABHD6. These data designate O-hydroxyacetamide carbamates as a versatile chemotype for creating endocannabinoid hydrolase inhibitors that display excellent in vivo activity and tunable selectivity for FAAH-anandamide versus MAGL (and ABHD6)-2-AG pathways.