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Unfolded protein response (UPR) is a stress response that is specific to the endoplasmic reticulum (ER). UPR is activated upon accumulation of unfolded (or misfolded) proteins in the ER's lumen to restore protein folding capacity by increasing the synthesis of chaperones. In addition, UPR also enhances degradation of unfolded proteins and reduces global protein synthesis to alleviate additional accumulation of unfolded proteins in the ER. Herein, we describe a cell-based ultra-high throughput screening (uHTS) campaign that identifies a small molecule that can modulate UPR and ER stress in cellular and in vivo disease models. Using asialoglycoprotein receptor 1 (ASGR) fused with Cypridina luciferase (CLuc) as reporter assay for folding capacity, we have screened a million small molecule library and identified APC655 as a potent activator of protein folding, that appears to act by promoting chaperone expression. Furthermore, APC655 improved pancreatic β cell viability and insulin secretion under ER stress conditions induced by thapsigargin or cytokines. APC655 was also effective in preserving β cell function and decreasing lipid accumulation in the liver of the leptin-deficient (ob/ob) mouse model. These results demonstrate a successful uHTS campaign that identified a modulator of UPR, which can provide a novel candidate for potential therapeutic development for a host of metabolic diseases., Graphical abstract A cell-based high throughput screening identified a small molecule that improves pancreatic beta cell viability and function through increased UPR chaperones and ER folding capacity.Image 1

[Image: see text] Anorexigenic peptides offer promise as potential therapies targeting the escalating global obesity epidemic. Prolactin-releasing peptide (PrRP), a novel member of the RFamide family secreted by the hypothalamus, shows therapeutic potential by decreasing food intake and body weight in rodent models via GPR10 activation. Here we describe the design of a long-acting PrRP using our recently developed novel multiple ethylene glycol-fatty acid (MEG-FA) stapling platform. By incorporating serum albumin binding fatty acids onto a covalent side chain staple, we have generated a series of MEG-FA stapled PrRP analogs with enhanced serum stability and in vivo half-life. Our lead compound 18-S4 exhibits good in vitro potency and selectivity against GPR10, improved serum stability, and extended in vivo half-life (7.8 h) in mouse. Furthermore, 18-S4 demonstrates a potent body weight reduction effect in a diet-induced obesity (DIO) mouse model, representing a promising long-acting PrRP analog for further evaluation in the chronic obesity setting.

Background and purpose Beta cell apoptosis is a major feature of type 1 diabetes, and pro-inflammatory cytokines are key drivers of the deterioration of beta cell mass through induction of apoptosis. Mitochondrial stress plays a critical role in mediating apoptosis by releasing cytochrome C into the cytoplasm, directly activating caspase-9 and its downstream signalling cascade. We aimed to identify new compounds that protect beta cells from cytokine-induced activation of the intrinsic (mitochondrial) pathway of apoptosis. Experimental approach Diabetogenic media, composed of IL-1β, IFN-γ and high glucose, were used to induce mitochondrial stress in rat insulin-producing INS1E cells, and a high-content image-based screen of small molecule modulators of Casp9 pathway was performed. Key results A novel small molecule, ATV399, was identified from a high-content image-based screen for compounds that inhibit cleaved caspase-9 activation and subsequent beta cell apoptosis induced by a combination of IL-1β, IFN-γ and high glucose, which together mimic the pathogenic diabetic milieu. Through medicinal chemistry optimization, potency was markedly improved (6-30 fold), with reduced inhibitory effects on CYP3A4. Improved analogues, such as CAT639, improved beta cell viability and insulin secretion in cytokine-treated rat insulin-producing INS1E cells and primary dispersed islet cells. Mechanistically, CAT639 reduced the production of NO by allosterically inhibiting dimerization of inducible NOS (iNOS) without affecting its mRNA levels. Conclusion and implications Taken together, these studies demonstrate a successful phenotypic screening campaign resulting in identification of an inhibitor of iNOS dimerization that protects beta cell viability and function through modulation of mitochondrial stress induced by cytokines.

Isoxazolines are oral insecticidal drugs currently licensed for ectoparasite control in companion animals. Here we propose their use in humans for the reduction of vector-borne disease incidence. Fluralaner and afoxolaner rapidly killed Anopheles, Aedes, and Culex mosquitoes and Phlebotomus sand flies after feeding on a drug-supplemented blood meal, with IC50 values ranging from 33 to 575 nM, and were fully active against strains with preexisting resistance to common insecticides. Based on allometric scaling of preclinical pharmacokinetics data, we predict that a single human median dose of 260 mg (IQR, 177-407 mg) for afoxolaner, or 410 mg (IQR, 278-648 mg) for fluralaner, could provide an insecticidal effect lasting 50-90 days against mosquitoes and Phlebotomus sand flies. Computational modeling showed that seasonal mass drug administration of such a single dose to a fraction of a regional population would dramatically reduce clinical cases of Zika and malaria in endemic settings. Isoxazolines therefore represent a promising new component of drug-based vector control.

Nonalcoholic fatty liver disease (NAFLD) is the result of the ectopic accumulation of lipids in hepatic cells and is the early stage of liver diseases including fibrosis, cirrhosis, and hepatocellular carcinoma. While some mechanisms of aberrant lipid storage are understood, unbiased phenotypic drug screening holds the potential to identify new therapeutic small molecule mechanisms that reverse lipid accumulation in hepatic cells and prevent disease progression. Immortalized hepatocyte cell lines are often used as in vitro models of hepatocyte function, including in the study of lipid accumulation. However, mechanisms and therapeutic agents studied in these systems suffer from poor translation to primary cells and animal models of disease. Herein, we report an ex vivo high-throughput screening platform using primary mouse hepatocytes with a physiologically relevant lipid-laden phenotype isolated from mice that are administered a choline-methionine deficient diet. This screening platform using primary diseased hepatocytes may help to overcome a major hurdle in liver disease drug discovery and could lead to the development of new therapeutics for hepatosteatosis.

The isolation and structure elucidation of six new bacterial metabolites [spoxazomicin D (2), oxachelins B and C (4, 5), and carboxamides 6–8] and 11 previously reported bacterial metabolites (1, 3, 9–12a, and 14–18) from Streptomyces sp. RM-14-6 is reported. Structures were elucidated on the basis of comprehensive 1D and 2D NMR and mass spectrometry data analysis, along with direct comparison to synthetic standards for 2, 11, and 12a,b. Complete 2D NMR assignments for the known metabolites lenoremycin (9) and lenoremycin sodium salt (10) were also provided for the first time. Comparative analysis also provided the basis for structural revision of several previously reported putative aziridine-containing compounds [exemplified by madurastatins A1, B1, C1 (also known as MBJ-0034), and MBJ-0035] as phenol-dihydrooxazoles. Bioactivity analysis [including antibacterial, antifungal, cancer cell line cytotoxicity, unfolded protein response (UPR) modulation, and EtOH damage neuroprotection] revealed 2 and 5 as potent neuroprotectives and lenoremycin (9) and its sodium salt (10) as potent UPR modulators, highlighting new functions for phenol-oxazolines/salicylates and polyether pharmacophores.

Phosphodiesterase 4 (PDE4) inhibitors are approved for the treatment of some moderate to severe inflammatory conditions. However, dose-limiting side effects in the central nervous system and gastrointestinal tract, including nausea, emesis, headache, and diarrhea, have impeded the broader therapeutic application of PDE4 inhibitors. We sought to exploit the wealth of validation surrounding PDE4 inhibition by improving the therapeutic index through generation of an antibody-drug conjugate (ADC) that selectively targets immune cells through the CD11a antigen. The resulting ADC consisted of a human αCD11a antibody (based on efalizumab clone hu1124) conjugated to an analog of the highly potent PDE4 inhibitor GSK256066. Both the human αCD11a ADC and a mouse surrogate αCD11a ADC (based on the M17 clone) rapidly internalized into immune cells and suppressed lipololysaccharide (LPS)-induced TNFα secretion in primary human monocytes and mouse peritoneal cells, respectively. In a carrageenan-induced air pouch inflammation mouse model, treatment with the ADC significantly reduced inflammatory cytokine production in the air pouch exudate. Overall, these results provide compelling evidence for the feasibility of delivering drugs with anti-inflammatory activity selectively to the immune compartment via CD11a and the development of tissue-targeted PDE4 inhibitors as a promising therapeutic modality for treating inflammatory diseases.

Liver X receptor (LXR), a nuclear hormone receptor, is an essential regulator of immune responses. Activation of LXR-mediated transcription by synthetic agonists, such as T0901317 and GW3965, attenuates progression of inflammatory disease in animal models. However, the adverse effects of these conventional LXR agonists in elevating liver lipids have impeded exploitation of this intriguing mechanism for chronic therapy. Here, we explore the ability of a series of sterol-based LXR agonists to alleviate inflammatory conditions in mice without hepatotoxicity. We show that oral treatment with sterol-based LXR agonists in mice significantly reduces dextran sulfate sodium colitis-induced body weight loss, which is accompanied by reduced expression of inflammatory markers in the large intestine. The anti-inflammatory property of these agonists is recapitulated in vitro in mouse lamina propria mononuclear cells, human colonic epithelial cells, and human peripheral blood mononuclear cells. In addition, treatment with LXR agonists dramatically suppresses inflammatory cytokine expression in a model of traumatic brain injury. Importantly, in both disease models, the sterol-based agonists do not affect the liver, and the conventional agonist T0901317 results in significant liver lipid accumulation and injury. Overall, these results provide evidence for the development of sterol-based LXR agonists as novel therapeutics for chronic inflammatory diseases.—Yu, S., Li, S., Henke, A., Muse, E. D., Cheng, B., Welzel, G., Chatterjee, A. K., Wang, D., Roland, J., Glass, C. K., Tremblay, M. Dissociated sterol-based liver X receptor agonists as therapeutics for chronic inflammatory diseases.

Significance The beneficial effects of LXR-pathway activation have long been appreciated, but clinical application of synthetic LXR ligands has been limited by coactivation of SREBP1c and consequent hypertriglyceridemia. Natural LXR ligands such as desmosterol do not promote hypertriglyceridemia because of coordinate down-regulation of the SREBP pathway. Here we demonstrate that synthetic desmosterol mimetics activate LXR in macrophages both in vitro and in vivo while suppressing SREBP target genes. Unexpectedly, desmosterol and synthetic desmosterol mimetics have almost no effect on LXR activity in hepatocytes in comparison with conventional synthetic LXR ligands. These findings reveal cell-specific differences in LXR responses to natural and synthetic ligands in macrophages and liver cells that provide a conceptually new basis for future drug development., Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of sterol regulatory element-binding protein (SREBP)1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c-induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytes in vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophages in vitro and in vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in the liver that lead to hypertriglyceridemia.

Activation of liver X receptors (LXRs) with synthetic agonists promotes reverse cholesterol transport and protects against atherosclerosis in mouse models. Most synthetic LXR agonists also cause marked hypertriglyceridemia by inducing the expression of SREBP1c and downstream genes that drive fatty acid biosynthesis. Recent studies demonstrated that desmosterol, an intermediate in the cholesterol biosynthetic pathway that suppresses SREBP processing by binding to SCAP, also binds and activates LXRs and is the most abundant LXR ligand in macrophage foam cells. Here, we explore the potential of increasing endogenous desmosterol production or mimicking its activity as a means of inducing LXR activity while simultaneously suppressing SREBP1c induced hypertriglyceridemia. Unexpectedly, while desmosterol strongly activated LXR target genes and suppressed SREBP pathways in mouse and human macrophages, it had almost no activity in mouse or human hepatocytesin vitro. We further demonstrate that sterol-based selective modulators of LXRs have biochemical and transcriptional properties predicted of desmosterol mimetics and selectively regulate LXR function in macrophagesin vitroandin vivo. These studies thereby reveal cell-specific discrimination of endogenous and synthetic regulators of LXRs and SREBPs, providing a molecular basis for dissociation of LXR functions in macrophages from those in liver that lead to hypertriglyceridemia.SIGNIFICANCE STATEMENTThe beneficial effects of LXR pathway activation in the prevention of atherosclerotic heart disease have long been appreciated. However, efforts to translate those effects in humans with synthetic LXR ligands has been met with the unintended consequence of hypertriglyceridemia, a product of co-activation of SREBP1c. Natural LXR ligands such as desmosterol do not promote hypertriglyceridemia because of coordinate down-regulation of the SREBP pathway. Here, we demonstrate that synthetic desmosterol mimetics activate LXR pathways macrophages both in vitro and in vivo without co-stimulation of SREBP1c. Unexpectedly, desmosterol and synthetic desmosterol mimetics almost no effect on LXR activity in hepatocytes in comparison to conventional synthetic LXR ligands. These findings reveal cell-specific differences in LXR responses to natural and synthetic ligands in macrophages and liver cells that provide a conceptually new basis for future drug development.

Most ADCs developed thus far have been explored for oncology indications. Emerging ADC technologies present many opportunities to apply the modality beyond oncology. The key variables for oncology ADCs in terms of the targeted cell type, targeting strategy, and payload are often clearer while the corresponding elements for non-oncology indications are more complex. Challenges in designing such non-oncology ADCs include selecting the targeting cell type(s) from among potentially several contributing to the disease, a distinct surface marker expressed on the targeting cells, which often overlaps healthy cells, and a potent, non-cytotoxic payload drug. So far, only a few ADCs were designed for non-oncology indications, with none yet successfully progressing through clinical trials. Here, we summarize those that have been reported. In addition, we discuss some considerations to be taken into account for designing ADCs for non-oncology indications, including payload and antibody selection. With the evolution of ADC platform and technology, more ADCs for non-oncology indications are yet to be developed.

We have developed a novel antibody drug-conjugate (ADC) which can selectively deliver the Lck inhibitor dasatinib to human T lymphocytes. This ADC is based on a humanized antibody which selectively binds with high affinity to CXCR4, an antigen that is selectively expressed on hematopoietic cells. The resulting dasatinib-antibody conjugate suppresses T-cell-receptor (TCR)-mediated T cell activation and cytokine expression with low nM EC50 and has minimal effects on cell viability. This ADC may lead to a new class of selective immunosuppressive drugs with improved safety, and extends the antibody-drug conjugate strategy to the targeted delivery of kinase inhibitors for indications beyond oncology.

BACKGROUND AND PURPOSE: Beta cell apoptosis is a major feature of type 1 diabetes, and pro‐inflammatory cytokines are key drivers of the deterioration of beta cell mass through induction of apoptosis. Mitochondrial stress plays a critical role in mediating apoptosis by releasing cytochrome C into the cytoplasm, directly activating caspase‐9 and its downstream signalling cascade. We aimed to identify new compounds that protect beta cells from cytokine‐induced activation of the intrinsic (mitochondrial) pathway of apoptosis. EXPERIMENTAL APPROACH: Diabetogenic media, composed of IL‐1β, IFN‐γ and high glucose, were used to induce mitochondrial stress in rat insulin‐producing INS1E cells, and a high‐content image‐based screen of small molecule modulators of Casp9 pathway was performed. KEY RESULTS: A novel small molecule, ATV399, was identified from a high‐content image‐based screen for compounds that inhibit cleaved caspase‐9 activation and subsequent beta cell apoptosis induced by a combination of IL‐1β, IFN‐γ and high glucose, which together mimic the pathogenic diabetic milieu. Through medicinal chemistry optimization, potency was markedly improved (6–30 fold), with reduced inhibitory effects on CYP3A4. Improved analogues, such as CAT639, improved beta cell viability and insulin secretion in cytokine‐treated rat insulin‐producing INS1E cells and primary dispersed islet cells. Mechanistically, CAT639 reduced the production of NO by allosterically inhibiting dimerization of inducible NOS (iNOS) without affecting its mRNA levels. CONCLUSION AND IMPLICATIONS: Taken together, these studies demonstrate a successful phenotypic screening campaign resulting in identification of an inhibitor of iNOS dimerization that protects beta cell viability and function through modulation of mitochondrial stress induced by cytokines.

Retinal pigment epithelial (RPE) cells form a monolayer adjacent to the retina and play a critical role in the visual light cycle. Degeneration of RPE cells results in retinal disorders such as age-related macular degeneration. Cell transplant strategies have potential therapeutic value for such disorders; however, risks associated with and an inadequate supply of donor cells limit their therapeutic success. The identification of factors that proliferate RPE cells ex vivo could provide a renewable source of cells for transplantation. Here we report that a small molecule (WS3) can reversibly proliferate primary RPE cells isolated from fetal and adult human donors. Following withdrawal of WS3, RPE cells differentiate into a functional monolayer, as exhibited by their expression of mature RPE genes and phagocytosis of photoreceptor outer segments. Furthermore, chemically expanded RPE cells preserve vision when transplanted into dystrophic Royal College of Surgeons (RCS) rats, a well-established model of retinal degeneration.

The identification of factors that promote β cell proliferation could ultimately move type 1 diabetes treatment away from insulin injection therapy and toward a cure. We have performed high-throughput, cell-based screens using rodent β cell lines to identify molecules that induce proliferation of β cells. Herein we report the discovery and characterization of WS6, a novel small molecule that promotes β cell proliferation in rodent and human primary islets. In the RIP-DTA mouse model of β cell ablation, WS6 normalized blood glucose and induced concomitant increases in β cell proliferation and β cell number. Affinity pulldown and kinase profiling studies implicate Erb3 binding protein-1 and the IκB kinase pathway in the mechanism of action of WS6.

Osteoarthritis and Kartogenin Osteoarthritis is characterized by progressive breakdown of articular cartilage and affects over 25 million people in the United States. Mesenchymal stem cells (MSCs), which reside in healthy and diseased joints, are multipotent adult stem cells that are able to differentiate into a variety of cell types. Johnson et al. (p. 717 , published online 5 April) identified a small molecule, kartogenin, which was able to induce MSCs to differentiate into chondrocytes in vitro. When administered locally, kartogenin was efficacious in two animal models of osteoarthritis.

Efficient intermolecular energy transfer from carbostyril 124-sensitized Tb(3+) to Eu(3+) in aqueous aggregates is reported. This energy transfer was also recapitulated on the cell surface of a human kidney cell line (HEK-293T) and imaged by fluorescence microscopy as an example for the applicability of this energy transfer probe for imaging in biological systems.

Liver X receptor (LXR) agonists have been explored as potential treatments for atherosclerosis and other diseases based on their ability to induce reverse cholesterol transport and suppress inflammation. However, this therapeutic potential has been hindered by on-target adverse effects in the liver mediated by excessive lipogenesis. Herein, we report a novel site-specific antibody-drug conjugate (ADC) that selectively delivers a LXR agonist to monocytes/macrophages while sparing hepatocytes. The unnatural amino acid para-acetylphenylalanine (pAcF) was site-specifically incorporated into anti-CD11a IgG, which binds the α-chain component of the lymphocyte function-associated antigen 1 (LFA-1) expressed on nearly all monocytes and macrophages. An aminooxy-modified LXR agonist was conjugated to anti-CD11a IgG through a stable, cathepsin B cleavable oxime linkage to afford a chemically-defined ADC. The anti-CD11a IgG-LXR agonist ADC induced LXR activation specifically in human THP-1 monocyte/macrophage cells in vitro (EC50 ~ 27 nM), but had no significant effect in hepatocytes, indicating that payload delivery is CD11a-mediated. Moreover, the ADC exhibited higher fold activation compared to a conventional synthetic LXR agonist T0901317 (Tularik) (~3 fold). This novel ADC represents a fundamentally different strategy that uses tissue targeting to overcome the limitations of LXR agonists for potential use in treating atherosclerosis.

[reaction: see text] A luminogenic probe for peptide dephosphorylation has been developed. It consists of a serine-/tyrosine-containing peptide modified on the N-terminus with a tryptophan residue and a DTPA chelate capable of binding Tb(3+). We propose a mechanistic model for the luminescence enhancement based on the interconversion of monomeric and dimeric lanthanide species, which is affected by the phosphorylation state of the serine or tyrosine residue. The optical switch reports effectively on phosphatase-catalyzed dephosphorylation in vitro.

[reaction: see text] A new fluorogenic transformation based on a quinone reduction/lactonization sequence has been developed and evaluated as a tool for probing redox phenomena in a biochemical context. The probe presented herein is an irreversible redox probe and is reduced selectively by biologically relevant quinols such as ubiquinol but is inert to reduced nicotinamides (e.g., NADH). The ensuing cyclization is fast and quantitative and provides a measurable optical response.

To identify small molecules that can induce beta-cell replication, a large chemical library was screened for proliferation of growth-arrested, reversibly immortalized mouse beta cells by using an automated high-throughput screening platform. A number of structurally diverse, active compounds were identified, including phorbol esters, which likely act through protein kinase C, and a group of thiophene-pyrimidines that stimulate beta-cell proliferation by activating the Wnt signaling pathway. A group of dihydropyridine (DHP) derivatives was also shown to reversibly induce beta-cell replication in vitro by activating L-type calcium channels (LTCCs). Our data suggest that the LTCC agonist 2a affects the expression of genes involved in cell cycle progression and cellular proliferation. Furthermore, treatment of beta cells with both LTCC agonist 2a and the Glp-1 receptor agonist Exendin-4 showed an additive effect on beta-cell replication. The identification of small molecules that induce beta-cell proliferation suggests that it may be possible to reversibly expand other quiescent cells to overcome deficits associated with degenerative and/or autoimmune diseases.

This study reports the development of a Nd(III)-based near-IR luminescent probe for monitoring aldo-ketoreductase (AKR) enzyme activity. We have adapted a coumarin-based reporter substrate for the AKR1C2 to a near-IR emitting format by tethering the former to a macrocyclic Nd(III) moiety via an alkyl linker. Enzymatic reduction of the ketone functionality on the coumarin alters the energy transfer efficiency from the fluorophore to the emitting lanthanide species, resulting in emission at ∼1060 nm from the alcohol product. The efficiency of sensitization is not significantly affected by extending the alkyl tether from two to three carbons, and even a six-carbon linker still supports viable sensitized luminescence. In addition, the suitability of these complexes to act as enzyme substrates improves with longer linker length. We have thus developed long wavelength luminogenic reporter substrates for a redox enzyme and also a general platform for transposing molecular fluorescence into the more desirable nea...

Fluorescent and luminescent reporters that signal molecular events of interest by modulating the ratio of peaks in their emission profile have advantages over reporters that simply modulate their emission intensity, since ratiometric measurement is concentration-independent and allows them to be effective in complex contexts, such as living cells or sensor microarrays. We herein describe a general platform for the design of ratiometric probes based on a heterometallic Tb(3+)/Eu(3+) bis-lanthanide ensemble, consisting of a mixture, or "cocktail", of otherwise identical heterometalated chelates. The chelate contains an organic photon antenna that sensitizes the Tb(3+)/Eu(3+) luminescence. The contributions of the two metals to the composite luminescence spectrum can be tuned to the same relative scale by adjusting the stoichiometry of the cocktail, allowing subtle changes in their ratio to be accurately measured. Importantly, the ratio responds to chemical and environmental changes experienced by the photon antenna, making the system an ideal platform for the design of chemical and enzymatic probes. As proofs of concept, we describe a ratiometric probe for esterase activity and a polarity-responsive ratiometric sensor.

Iodotrimethylsilane (TMSI), routinely used for the dealkylation of ethers and esters, has been found to efficiently convert allyl and benzyl phosphotriesters into the corresponding iodides under mild, Bronsted-neutral conditions. In contrast, alkyl and aryl phosphotriesters were dealkylated to the corresponding phosphates under identical conditions.

A modular synthetic method for the differential incorporation of two lanthanide ions into a single molecular scaffold is reported; the mixed bimetallic Tb/Eu complex displays an interesting solvent polarity-dependent ratiometric luminescence.

Page 1672. Eric C. Peters was mistakenly listed in the Acknowledgment of the published Communication rather than in the author list. Eric C. Peters should be included in the author list between Jonathan G. Swoboda and Charles Y. Cho, along with indication (‡) of his affiliation with The Genomics Institute of the Novartis Research Foundation. The first sentence of the Acknowledgment should now read as follows: The authors acknowledge the efforts of John Walker for experimental support.