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Deletion of pregnancy-associated plasma protein-A (PAPP-A), a protease that cleaves some but not all IGF1 binding proteins, postpones late-life diseases and extends lifespan in mice, but the mechanism of this effect is unknown. Here we show that PAPP-A knockout (PKO) mice display a set of changes, in multiple tissues, that are characteristic of other varieties of slow-aging mice with alterations in GH production or GH responsiveness, including Ames dwarf, Snell dwarf, and GHRKO mice. PKO mice have elevated UCP1 in brown and white adipose tissues (WAT), and a change in fat-associated macrophage subsets that leads to diminished production of inflammatory cytokines. PKO mice also show increased levels of muscle FNDC5 and its cleavage product, the myokine irisin, thought to cause changes in fat cell differentiation. PKO mice have elevated production of hepatic GPLD1 and plasma GPLD1, consistent with their elevation of hippocampal BDNF and DCX, used as indices of neurogenesis. In contrast, disruption of PAPP-A limited to muscle (“muPKO” mice) produces an unexpectedly complex set of changes, in most cases opposite in direction from those seen in PKO mice. These include declines in WAT UCP1, increases in inflammatory macrophages and cytokines in WAT, and a decline in muscle FNDC5 and plasma irisin. muPKO mice do, however, resemble global PKO mice in their elevation of hippocampal BDNF and DCX. The data for the PKO mice support the idea that these changes in fat, macrophages, liver, muscle, plasma, and brain are consistent and biologically significant features of the slow-aging phenotype in mice. The results on the muPKO mice provide a foundation for further investigation of the complex, local, and global circuits by which PAPP-A modulates signals ordinarily controlled by GH and/or IGF1. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11357-022-00692-3.

The key protein implicated in Parkinson's disease and other synucleinopathies is α-synuclein, and a post-translationally modified form of the protein, phosphorylated at serine 129 (pS129), is a principal component in Lewy bodies, a pathological hallmark of PD. While altered proteostasis has been implicated in the etiology of Parkinson's disease, we still have a limited understanding of how α-synuclein is regulated in the nervous system. The protein quality control protein Ubiquilin-2 (UBQLN2) is known to accumulate in synucleinopathies, but whether it directly regulates α-synuclein is unknown. Using cellular and mouse models, we find that UBQLN2 decreases levels of α-synuclein, including the pS129 phosphorylated isoform. Pharmacological inhibition of the proteasome revealed that, while α-synuclein may be cleared by parallel and redundant quality control pathways, UBQLN2 preferentially targets pS129 for proteasomal degradation. Moreover, in brain tissue from human PD and transgenic mice expressing pathogenic α-synuclein (A53T), native UBQLN2 becomes more insoluble. Collectively, our studies support a role for UBQLN2 in directly regulating pathological forms of α-synuclein and indicate that UBQLN2 dysregulation in disease may contribute to α-synuclein-mediated toxicity.

Heart failure (HF) is defined as an inability of the heart to pump blood sufficiently to meet the metabolic demands of the body. HF with systolic dysfunction is caused by a progressive decline in contractile function and chronic hemodynamic overload, and characterized by ventricular hypertrophy and remodeling, neurohormonal compensation mechanisms, and myocardial damage. Transverse aortic constriction (TAC) is a well-established model for inducing hypertrophy and HF in rodents. Mice globally deficient in sirtuin 5 (SIRT5), a NAD + -dependent deacylase, are hypersensitive to cardiac stress and display increased mortality after TAC. Prior studies assessing SIRT5 functions in the heart have all employed loss-of-function approaches. In this study, we generated SIRT5 overexpressing (SIRT5OE) mice, and evaluated their response to chronic pressure overload using TAC. Compared to littermate controls, elevated SIRT5 levels promoted maintenance of cardiac contractile function after 4 weeks of pressure overload, at which point control mice had developed systolic dysfunction, characterized by decreased EF, coupled with ventricular dilation, remodeling and fibrosis. Transcriptomic analysis revealed that SIRT5 suppresses key HF sequelae, including metabolic switch from fatty acid oxidation to glycolysis and immune activation ( i.e., TGFβ, IL6, Renin-Angiotensin, and NFAT, and fibrotic signaling pathways). We conclude that SIRT5 is a limiting factor in the preservation of cardiac function in response to experimental pressure overload.

The diabetes drug canagliflozin extends life span in male mice. Since malignant neoplasms are the major cause of death in most mouse strains, this observation suggests that canagliflozin might exert anti-neoplastic effects in male mice. Here, we treated a mouse neoplasia model, the adenoma-prone ApcMin/+ strain, with canagliflozin, to test the effects of this drug on intestinal tumor burden. Surprisingly, canagliflozin increased the total area of intestine involved by adenomas, an effect most marked in the distal intestine and in female mice. Immunohistochemical analysis suggested that canagliflozin may not influence adenoma growth via direct SGLT1/2 inhibition in neoplastic cells. Our results are most consistent with a model where canagliflozin aggravates adenoma development by altering the anatomic distribution of intestinal glucose absorption, as evidenced by increases in postprandial GLP-1 levels driven by delayed glucose absorption. We hypothesize that canagliflozin exacerbates adenomatosis in the ApcMin/+ model via complex, cell-non-autonomous mechanisms, and that sex differences in GLP-1 responses may in part underlie sexually dimorphic effects of this drug on life span.

Heart failure (HF) is defined as an inability of the heart to pump blood adequately to meet the body’s metabolic demands. HF with reduced systolic function is characterized by cardiac hypertrophy, ventricular fibrosis and remodeling, and decreased cardiac contractility, leading to cardiac functional impairment and death. Transverse aortic constriction (TAC) is a well-established model for inducing hypertrophy and HF in rodents. Mice globally deficient in sirtuin 5 (SIRT5), a NAD+-dependent deacylase, are hypersensitive to cardiac stress and display increased mortality after TAC. Prior studies assessing SIRT5 functions in the heart have all employed loss-of-function approaches. In this study, we generated SIRT5 overexpressing (SIRT5OE) mice, and evaluated their response to chronic pressure overload induced by TAC. Compared to littermate controls, SIRT5OE mice were protected from left ventricular dilation and impaired ejection fraction, adverse functional consequences of TAC. Transcriptomic analyses revealed that SIRT5 suppresses key HF sequelae, including the metabolic switch from fatty acid oxidation to glycolysis, immune activation, and increased fibrotic signaling. We conclude that SIRT5 is a limiting factor in the preservation of cardiac function in response to experimental pressure overload.

Cutaneous melanoma remains the most lethal skin cancer, and ranks third among all malignancies in terms of years of life lost. Despite the advent of immune checkpoint and targeted therapies, only roughly half of patients with advanced melanoma achieve a durable remission. Sirtuin 5 (SIRT5) is a member of the sirtuin family of protein deacylases that regulates metabolism and other biological processes. Germline Sirt5 deficiency is associated with mild phenotypes in mice. Here we showed that SIRT5 was required for proliferation and survival across all cutaneous melanoma genotypes tested, as well as uveal melanoma, a genetically distinct melanoma subtype that arises in the eye and is incurable once metastatic. Likewise, SIRT5 was required for efficient tumor formation by melanoma xenografts and in an autochthonous mouse Braf Pten–driven melanoma model. Via metabolite and transcriptomic analyses, we found that SIRT5 was required to maintain histone acetylation and methylation levels in melanoma cells, thereby promoting proper gene expression. SIRT5-dependent genes notably included MITF, a key lineage-specific survival oncogene in melanoma, and the c-MYC proto-oncogene. SIRT5 may represent a druggable genotype-independent addiction in melanoma.

Cutaneous melanoma remains the most lethal skin cancer, and ranks third among all malignancies in terms of years of life lost. Despite the advent of immune checkpoint and targeted therapies, only roughly half of patients with advanced melanoma achieves a durable remission. SIRT5 is a member of the sirtuin family of protein deacylases that regulate metabolism and other biological processes. Germline Sirt5 deficiency is associated with mild phenotypes in mice. Here we show that SIRT5 is required for proliferation and survival across all cutaneous melanoma genotypes tested, as well as uveal melanoma, a genetically distinct melanoma subtype that arises in the eye and is incurable once metastatic. Likewise, SIRT5 is required for efficient tumor formation by melanoma xenografts and in an autochthonous mouse Braf;Pten-driven melanoma model. Via metabolite and transcriptomic analyses, we find that SIRT5 is required to maintain histone acetylation and methylation levels in melanoma cells, thereby promoting proper gene expression. SIRT5-dependent genes notably include MITF, a key lineage-specific survival oncogene in melanoma, and the c-MYC proto-oncogene. SIRT5 may represent a novel, druggable genotype-independent addiction in melanoma.

Control of inflammation is critical for the treatment of non-healing wounds, but a delicate balance exists between early inflammation that is essential for normal tissue repair and the pathologic inflammation that can occur later in the repair process. This necessitates the development of novel therapies that can target inflammation at the appropriate time during repair. Here, we found that SIRT3 is essential for normal healing and regulates inflammation in wound macrophages post-injury. Under ‘pre-diabetic’ conditions, SIRT3 was decreased in wound macrophages and resulted in dysregulated inflammation. Further, we found that FABP4 regulates SIRT3 in human blood monocytes and inhibiting FABP4 in wound macrophages decreases inflammatory cytokine expression making FABP4 a viable target for the regulation of excess inflammation and wound repair in diabetes. Using a series of ex vivo and in vivo studies with genetically engineered mouse models, as well as diabetic human monocytes, we demonstrate that FABP4 expression is epigenetically upregulated in diabetic wound macrophages and, in turn, diminishes SIRT3 expression thereby promoting inflammation. These findings have significant implications for controlling inflammation and promoting tissue repair in diabetic wounds.

Protein function is regulated by diverse posttranslational modifications. The mitochondrial sirtuin SIRT5 removes malonyl and succinyl moieties from target lysines. The spectrum of protein substrates subject to these modifications is unknown. We report systematic profiling of the mammalian succinylome, identifying 2,565 succinylation sites on 779 proteins. Most of these do not overlap with acetylation sites, suggesting differential regulation of succinylation and acetylation. Our analysis reveals potential impacts of lysine succinylation on enzymes involved in mitochondrial metabolism; e.g., amino acid degradation, the tricarboxylic acid cycle (TCA) cycle, and fatty acid metabolism. Lysine succinylation is also present on cytosolic and nuclear proteins; indeed, we show that a substantial fraction of SIRT5 is extra-mitochondrial. SIRT5 represses biochemical activity of, and cellular respiration through, two protein complexes identified in our analysis, pyruvate dehydrogenase complex and succinate dehydrogenase. Our data reveal widespread roles for lysine succinylation in regulating metabolism and potentially other cellular functions.

Synthetic opiates (opioids) have created among the most profitable markets worldwide. Two decades ago, FDA approval of Oxycontin® as a “minimally addictive” opioid pain reliever fueled an unprecedented rise in prescription opioid abuse. This was followed by a little known act of U.S. Congress enabling general physicians to use an opioid maintenance medication, buprenorphine, for addiction treatment in their private practices, leading to enormous growth in the U.S. addiction treatment market. Based on participant-observation and interviews among pharmaceutical executives, policy makers, patients and prescribers, this article describes the neuroeconomics and neuropolitics of new opioid maintenance treatments. This article contrasts the historical emergence of methadone clinics from the 1960s to the 1980s as a treatment for the Black and Latino urban poor, with the current emergence of buprenorphine, a maintenance opioid approved for prescription on doctor's offices, as a treatment for white, middle-class prescription opioid abusers. The article then traces the counterintuitive result of bringing addiction pharmaceuticals into the medical mainstream in an effort to reduce the stigma of addiction: a two tiered system of addiction treatment that reinforces stigma among the urban poor, and enhances the biological, political, and economic dependence of all classes on opioid markets, both legal and illegal.

A Roche 454 cDNA deep sequencing experiment was performed on a developing corm of Amorphophallus konjac—also known as voodoo lily. The dominant storage polymer in the corm of this plant is the polysaccharide glucomannan, a hemicellulose known to exist in the cell walls of higher plants and a major component of plant biomass derived from softwoods. A total of 246 mega base pairs of sequence data was obtained from which 4,513 distinct contigs were assembled. Within this voodoo lily expressed sequence tag collection genes representing the carbohydrate related pathway of glucomannan biosynthesis were identified, including sucrose metabolism, nucleotide sugar conversion pathways for the formation of activated precursors as well as a putative glucomannan synthase. In vivo expression of the putative glucomannan synthase and subsequent in vitro activity assays unambiguously demonstrate that the enzyme has indeed glucomannan mannosyl- and glucosyl transferase activities. Based on the expressed sequence tag analysis hitherto unknown pathways for the synthesis of GDP-glucose, a necessary precursor for glucomannan biosynthesis, could be proposed. Moreover, the results highlight transcriptional bottlenecks for the synthesis of this hemicellulose. Electronic supplementary material The online version of this article (doi:10.1007/s00425-011-1422-z) contains supplementary material, which is available to authorized users.

Metastatic melanoma is the deadliest form of skin cancer that still has limited treatment options and dismal 5-year year survival rates as low as 15%. Only recently has there been significant progress in the treatment of metastatic melanoma, advent by molecular targeted drugs and immunotherapy, but their limitations are exposed as these cancers are quickly able to develop resistance. Dysregulation of apoptotic machinery in melanoma allows the cancer cells to evade cell death and contributes to treatment resistance. Up-regulation of Mcl-1, a member of the Bcl-2 family of anti-apoptotic proteins, has been correlated with melanoma progression and metastasis. Mcl-1 amplification is one of the most common genetic aberrations found in human cancers and has been labeled as a marker of aggressive oncogenesis and poor patient prognosis. Previous studies have pointed to Mcl-1 as a viable therapeutic target for the treatment of melanoma and conclude that small molecule Mcl-1 inhibitors may appeal this unmet medical need. We have discovered and characterized a new class of selective small molecule Mcl-1 inhibitors using various biochemical, functional, and cell based assays; further development of these compounds allowed us to achieve potent low-nanomolar binding affinity for Mcl-1 and more than 300-fold selectivity over Bcl-2/Bcl-xL. Our most potent inhibitor, 483-LM, was screened across a panel of human melanoma cell lines using a cell proliferation assay and revealed varying levels of sensitivity. A BH3 profiling assay demonstrates that C8161, the cell line most sensitive to our inhibitor, solely relies on Mcl-1 for survival. The Mcl-1 dependence of C8161 might contribute to the known metastatic nature of this cell line. Mechanistic studies revealed that 483-LM effectively engaged the endogenous Mcl-1 protein after treatment of C8161, as determined by a CETSA assay, and prompted disruption of protein-protein interactions between Mcl-1 and several pro-apoptotic proteins, including Bax, Bak and Bim. This was followed by induction of Bax/Bak dependent apoptosis and activation of hallmarks of the intrinsic apoptotic pathway, including mitochondrial outer membrane depolarization, caspase activation, and PARP cleavage. Importantly, treatment with 483-LM caused massive up-regulation of the pro-apoptotic BH3-only protein Noxa, an effect apparent after an 8 hour treatment, which contributes to the induction of cell death. The in vivo efficacy studies with 483-LM showed significant effect on tumor growth and caspase-3 activation in tumor samples. Overall, our data indicate that Mcl-1 inhibitors are a promising treatment option for aggressive metastatic melanoma and warrant further preclinical investigation of 483-LM as a promising selective Mcl-1 inhibitor to be used as a single agent and in combination with chemotherapy and immunotherapy. Citation Format: Karson J. Kump, Lei Miao, Ahmed S. Mady, Katherine Lev, William Giblin, Mary E. Skinner, David B. Lombard, Zaneta Nikolovska-Coleska. A novel selective Mcl-1 inhibitor exhibits in vitro and in vivo efficacy in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1173. doi:10.1158/1538-7445.AM2017-1173

The first link between sirtuins and longevity was made 15 years ago in yeast. These initial studies sparked efforts by many laboratories working in diverse model organisms to elucidate the relationships between sirtuins, lifespan, and age-associated dysfunction. Here we discuss the current understanding of how sirtuins relate to aging. We focus primarily on mammalian sirtuins SIRT1, SIRT3, and SIRT6, the three sirtuins for which the most relevant data are available. Strikingly, a large body of evidence now indicates that these and other mammalian sirtuins suppress a variety of age-related pathologies and promote healthspan. Moreover, increased expression of SIRT1 or SIRT6 extends mouse lifespan. Overall, these data point to important roles for sirtuins in promoting mammalian health, and perhaps in modulating the aging process.

Improved sample preparation techniques and increasingly sensitive mass spectrometry (MS) analysis have revolutionized the study of protein post-translational modifications (PTMs) (Rush et al., Nat Biotechnol 23:94-101, 2005). Here, we describe a general approach for immunopurification and MS-based identification of acetylated proteins in biological samples. This approach is useful to characterize changes in the acetylome in response to biological interventions (Schwer et al., Aging Cell 8:604-606, 2009).

Contains fulltext : 55700.pdf (Publisher’s version ) (Closed access) Nonconsciously activated goals and consciously set goals produce the same outcomes by engaging similar psychological processes (Bargh, 1990; Gollwitzer & Bargh, 2005). However, nonconscious and conscious goal pursuit may have different effects on subsequent affect if goal pursuit affords an explanation, as nonconscious goal pursuit occurs in an explanatory vacuum (i.e. cannot be readily attributed to the respective goal intention). We compared self-reported affect after nonconscious versus conscious goal pursuit that either violated or conformed to a prevailing social norm. When goal-directed behavior did not require an explanation (was norm-conforming), affective experiences did not differ after nonconscious and conscious goal pursuit. However, when goal-directed behavior required an explanation (was norm-violating), nonconscious goal pursuit induced more negative affect than conscious goal pursuit. 8 p.