Modulation of caveolae by insulin/IGF-1 signaling regulates aging of Caenorhabditis elegans.

Reducing insulin/IGF-1 signaling (IIS) extends lifespan, promotes protein homeostasis (proteostasis), and elevates stress resistance of worms, flies, and mammals. How these functions are orchestrated across the organism is only partially understood. Here, we report that in the nematode Caenorhabditis elegans, the IIS positively regulates the expression of caveolin-1 (cav-1), a gene which is primarily expressed in neurons of the adult worm and underlies the formation of caveolae, a subtype of lipid microdomains that serve as platforms for signaling complexes. Accordingly, IIS reduction lowers cav-1 expression and lessens the quantity of neuronal caveolae. Reduced cav-1 expression extends lifespan and mitigates toxic protein aggregation by modulating the expression of aging-regulating and signaling-promoting genes. Our findings define caveolae as aging-governing signaling centers and underscore the potential for cav-1 as a novel therapeutic target for the promotion of healthy aging.

Implementation of eHealth and AI integrated diagnostics with multidisciplinary digitized data: are we ready from an international perspective?

Digitization of medicine requires systematic handling of the increasing amount of health data to improve medical diagnosis. In this context, the integration of the versatile diagnostic information, e.g., from anamnesis, imaging, histopathology, and clinical chemistry, and its comprehensive analysis by artificial intelligence (AI)-based tools is expected to improve diagnostic precision and the therapeutic conduct. However, the complex medical environment poses a major obstacle to the translation of integrated diagnostics into clinical research and routine. There is a high need to address aspects like data privacy, data integration, interoperability standards, appropriate IT infrastructure, and education of staff. Besides this, a plethora of technical, political, and ethical challenges exists. This is complicated by the high diversity of approaches across Europe. Thus, we here provide insights into current international activities on the way to digital comprehensive diagnostics. This includes a technical view on challenges and solutions for comprehensive diagnostics in terms of data integration and analysis. Current data communications standards and common IT solutions that are in place in hospitals are reported. Furthermore, the international hospital digitalization scoring and the European funding situation were analyzed. In addition, the regional activities in radiomics and the related publication trends are discussed. Our findings show that prerequisites for comprehensive diagnostics have not yet been sufficiently established throughout Europe. The manifold activities are characterized by a heterogeneous digitization progress and they are driven by national efforts. This emphasizes the importance of clear governance, concerted investments, and cooperation at various levels in the health systems.Key Points• Europe is characterized by heterogeneity in its digitization progress with predominantly national efforts. Infrastructural prerequisites for comprehensive diagnostics are not given and not sufficiently funded throughout Europe, which is particularly true for data integration.• The clinical establishment of comprehensive diagnostics demands for a clear governance, significant investments, and cooperation at various levels in the healthcare systems.• While comprehensive diagnostics is on its way, concerted efforts should be taken in Europe to get consensus concerning interoperability and standards, security, and privacy as well as ethical and legal concerns.

Alzheimer's disease-causing proline substitutions lead to presenilin 1 aggregation and malfunction.

Do different neurodegenerative maladies emanate from the failure of a mutual protein folding mechanism? We have addressed this question by comparing mutational patterns that are linked to the manifestation of distinct neurodegenerative disorders and identified similar neurodegeneration-linked proline substitutions in the prion protein and in presenilin 1 that underlie the development of a prion disorder and of familial Alzheimer's disease (fAD), respectively. These substitutions were found to prevent the endoplasmic reticulum (ER)-resident chaperone, cyclophilin B, from assisting presenilin 1 to fold properly, leading to its aggregation, deposition in the ER, reduction of γ-secretase activity, and impaired mitochondrial distribution and function. Similarly, reduced quantities of the processed, active presenilin 1 were observed in brains of cyclophilin B knockout mice. These discoveries imply that reduced cyclophilin activity contributes to the development of distinct neurodegenerative disorders, propose a novel mechanism for the development of certain fAD cases, and support the emerging theme that this disorder can stem from aberrant presenilin 1 function. This study also points at ER chaperones as targets for the development of counter-neurodegeneration therapies.

Interleukin-1 Beta-A Friend or Foe in Malignancies?

Interleukin-1 beta (IL-1ß) is induced by inflammatory signals in a broad number of immune cell types. IL-1ß (and IL-18) are the only cytokines which are processed by caspase-1 after inflammasome-mediated activation. This review aims to summarize current knowledge about parameters of regulation of IL-1ß expression and its multi-facetted role in pathophysiological conditions. IL-1 signaling activates innate immune cells including antigen presenting cells, and drives polarization of CD4+ T cells towards T helper type (Th) 1 and Th17 cells. Therefore, IL-1ß has been attributed a largely beneficial role in resolving acute inflammations, and by initiating adaptive anti-tumor responses. However, IL-1ß generated in the course of chronic inflammation supports tumor development. Furthermore, IL-1ß generated within the tumor microenvironment predominantly by tumor-infiltrating macrophages promotes tumor growth and metastasis via different mechanisms. These include the expression of IL-1 targets which promote neoangiogenesis and of soluble mediators in cancer-associated fibroblasts that evoke antiapoptotic signaling in tumor cells. Moreover, IL-1 promotes the propagation of myeloid-derived suppressor cells. Using genetic mouse models as well as agents for pharmacological inhibition of IL-1 signaling therapeutically applied for treatment of IL-1 associated autoimmune diseases indicate that IL-1ß is a driver of tumor induction and development.

The inhibition of IGF-1 signaling promotes proteostasis by enhancing protein aggregation and deposition.

The discovery that the alteration of aging by reducing the activity of the insulin/IGF-1 signaling (IIS) cascade protects nematodes and mice from neurodegeneration-linked, toxic protein aggregation (proteotoxicity) raises the prospect that IIS inhibitors bear therapeutic potential to counter neurodegenerative diseases. Recently, we reported that NT219, a highly efficient IGF-1 signaling inhibitor, protects model worms from the aggregation of amyloid ß peptide and polyglutamine peptides that are linked to the manifestation of Alzheimer's and Huntington's diseases, respectively. Here, we employed cultured cell systems to investigate whether NT219 promotes protein homeostasis (proteostasis) in mammalian cells and to explore its underlying mechanisms. We found that NT219 enhances the aggregation of misfolded prion protein and promotes its deposition in quality control compartments known as "aggresomes." NT219 also elevates the levels of certain molecular chaperones but, surprisingly, reduces proteasome activity and impairs autophagy. Our findings show that IGF-1 signaling inhibitors in general and NT219 in particular can promote proteostasis in mammalian cells by hyperaggregating hazardous proteins, thereby bearing the potential to postpone the onset and slow the progression of neurodegenerative illnesses in the elderly.-Moll, L., Ben-Gedalya, T., Reuveni, H., Cohen, E. The inhibition of IGF-1 signaling promotes proteostasis by enhancing protein aggregation and deposition.

A short peptide protects from age-onset proteotoxicity.

Aberrant protein aggregation jeopardizes cellular functionality and underlies the development of a myriad of late-onset maladies including Alzheimer's disease (AD) and Huntington's disease (HD). Accordingly, molecules that mitigate the toxicity of hazardous protein aggregates are of great interest as potential future therapeutics. Here we asked whether a small peptide, composed of five amino acids (5MER peptide) that was derived from the human pro-inflammatory CD44 protein, could protect model nematodes from the toxicity of aggregative proteins that underlie the development of neurodegenerative disorders in humans. We found that the 5MER peptide mitigates the toxicity that stems from both; the AD-causing Aß peptide and a stretch of poly-glutamine that is accountable for the development of several disorders including HD, while minimally affecting lifespan. This protection was dependent on the activity of aging-regulating transcription factors and associated with enhanced Aß and polyQ35-YFP aggregation. A transcriptomic analysis unveiled that the peptide modifies signaling pathways, thereby modulating the expression of various genes, including these, which are known as protein homeostasis (proteostasis) regulators such as txt-13 and modifiers of proteasome activity. The knockdown of txt-13 protects worms from proteotoxicity to the same extent as the 5MER peptide, suggesting that the peptide activates the transcellular chaperone signaling to promote proteostasis. Together, our results propose that the 5MER peptide should be considered as a component of future therapeutic cocktails for the treatment of neurodegenerative maladies.

Insulin receptor substrate-1 and -2 mediate resistance to glucose-induced caspase-3 activation in human neuroblastoma cells.

Hyperglycemia in patients with type 2 diabetes causes multiple neuronal complications, e.g., diabetic polyneuropathy, cognitive decline, and embryonic neural crest defects due to increased apoptosis. Possible mechanisms of neuronal response to increased glucose burden are still a matter of debate. Insulin and insulin-like growth factor-1 (IGF-1) receptor signaling inhibits glucose-induced caspase-3 activation and apoptotic cell death. The insulin receptor substrates (IRS) are intracellular adapter proteins mediating insulin's and IGF-1's intracellular effects. Even though all IRS proteins have similar function and structure, recent data suggest different actions of IRS-1 and IRS-2 in mediating their anti-apoptotic effects in glucose neurotoxicity. We therefore investigated the role of IRS-1/-2 in glucose-induced caspase-3 activation using human neuroblastoma cells. Overexpression of IRS-1 or IRS-2 caused complete resistance to glucose-induced caspase-3 cleavage. Inhibition of PI3-kinase reversed this protective effect of IRS-1 or IRS-2. However, MAP-kinases inhibition had only minor impact. IRS overexpression increased MnSOD abundance as well as BAD phosphorylation while Bim and BAX levels remained unchanged. Since Akt promotes cell survival at least partially via phosphorylation and inhibition of downstream forkhead box-O (FoxO) transcription factors, we generated neuroblastoma cells stably overexpressing a dominant negative mutant of FoxO1 mimicking activation of the insulin/IGF-1 pathway on FoxO-mediated transcription. Using these cells we showed that FoxO1 is not involved in neuronal protection mediated by increased IRS-1/-2 expression. Thus, overexpression of both IRS-1 and IRS-2 induces complete resistance to glucose-induced caspase-3 activation via PI3-kinase mediated BAD phosphorylation and MnSOD expression independent of FoxO1.

Neuropeptide signaling and SKN-1 orchestrate differential responses of the proteostasis network to dissimilar proteotoxic insults.

The protein homeostasis (proteostasis) network (PN) encompasses mechanisms that maintain proteome integrity by controlling various biological functions. Loss of proteostasis leads to toxic protein aggregation (proteotoxicity), which underlies the manifestation of neurodegeneration. How the PN responds to dissimilar proteotoxic challenges and how these responses are regulated at the organismal level are largely unknown. Here, we report that, while torsin chaperones protect from the toxicity of neurodegeneration-causing polyglutamine stretches, they exacerbate the toxicity of the Alzheimer's disease-causing Aß peptide in neurons and muscles. These opposing effects are accompanied by differential modulations of gene expression, including that of three neuropeptides that are involved in tailoring the organismal response to dissimilar proteotoxic insults. This mechanism is regulated by insulin/IGF signaling and the transcription factor SKN-1/NRF. Our work delineates a mechanism by which the PN orchestrates differential responses to dissimilar proteotoxic challenges and points at potential targets for therapeutic interventions.

RhoA as a Key Regulator of Innate and Adaptive Immunity.

RhoA is a ubiquitously expressed cytoplasmic protein that belongs to the family of small GTPases. RhoA acts as a molecular switch that is activated in response to binding of chemokines, cytokines, and growth factors, and via mDia and the ROCK signaling cascade regulates the activation of cytoskeletal proteins, and other factors. This review aims to summarize our current knowledge on the role of RhoA as a general key regulator of immune cell differentiation and function. The contribution of RhoA for the primary functions of innate immune cell types, namely neutrophils, macrophages, and conventional dendritic cells (DC) to (i) get activated by pathogen-derived and endogenous danger signals, (ii) migrate to sites of infection and inflammation, and (iii) internalize pathogens has been fairly established. In activated DC, which constitute the most potent antigen-presenting cells of the immune system, RhoA is also important for the presentation of pathogen-derived antigen and the formation of an immunological synapse between DC and antigen-specific T cells as a prerequisite to induce adaptive T cell responses. In T cells and B cells as the effector cells of the adaptive immune system Rho signaling is pivotal for activation and migration. More recently, mutations of Rho and Rho-modulating factors have been identified to predispose for autoimmune diseases and as causative for hematopoietic malignancies.

The Protein Corona as a Confounding Variable of Nanoparticle-Mediated Targeted Vaccine Delivery.

Nanocarriers (NC) are very promising tools for cancer immunotherapy. Whereas conventional vaccines are based on the administration of an antigen and an adjuvant in an independent fashion, nanovaccines can facilitate cell-specific co-delivery of antigen and adjuvant. Furthermore, nanovaccines can be decorated on their surface with molecules that facilitate target-specific antigen delivery to certain antigen-presenting cell types or tumor cells. However, the target cell-specific uptake of nanovaccines is highly dependent on the modifications of the nanocarrier itself. One of these is the formation of a protein corona around NC after in vivo administration, which may potently affect cell-specific targeting and uptake of the NC. Understanding the formation and composition of the protein corona is, therefore, of major importance for the use of nanocarriers in vaccine approaches. This Mini Review will give a short overview of potential non-specific interactions of NC with body fluids or cell surfaces that need to be considered for the design of NC vaccines for immunotherapy of cancer.

The insulin/IGF signaling cascade modulates SUMOylation to regulate aging and proteostasis in Caenorhabditis elegans.

Although aging-regulating pathways were discovered a few decades ago, it is not entirely clear how their activities are orchestrated, to govern lifespan and proteostasis at the organismal level. Here, we utilized the nematode Caenorhabditis elegans to examine whether the alteration of aging, by reducing the activity of the Insulin/IGF signaling (IIS) cascade, affects protein SUMOylation. We found that IIS activity promotes the SUMOylation of the germline protein, CAR-1, thereby shortening lifespan and impairing proteostasis. In contrast, the expression of mutated CAR-1, that cannot be SUMOylated at residue 185, extends lifespan and enhances proteostasis. A mechanistic analysis indicated that CAR-1 mediates its aging-altering functions, at least partially, through the notch-like receptor glp-1. Our findings unveil a novel regulatory axis in which SUMOylation is utilized to integrate the aging-controlling functions of the IIS and of the germline and provide new insights into the roles of SUMOylation in the regulation of organismal aging.

Selective manipulation of aging: a novel strategy for the treatment of neurodegenerative disorders.

Aging is the major risk factor for the development of human neurodegenerative maladies such as Alzheimer's, Huntington's and Parkinson's diseases, and prion disorders, all of which stem from toxic protein aggregation. Although sporadic cases typically onset during the patient's seventh decade of life or later, mutation-linked, familial disorders manifest during the fifth or sixth decade of life. This common temporal emergence pattern suggests that slowing aging can postpone the onset of these maladies and alleviate their symptoms once emerged. Studies in worms and flies that express disease-linked aggregative proteins revealed that reducing the activity of the insulin / insulin-like growth factor (IGF) signalling (IIS), a prominent aging regulatory pathway, protects these animals from toxic protein aggregation. The therapeutic potential of this approach has been tested and confirmed in mammals as reducing the activity of the IGF1 signalling cascade partially protects Alzheimer's-model mice from premature death, and behavioural and pathological impairments associated with the disorder. Here we review the recent advances in the field, describe the known mechanistic links between toxic protein aggregation, neurodegenerative disorders and the aging process and delineate recent studies that point at IGF1 signalling inhibitors as promising therapies for the treatment of various late-onset neurodegenerative disorders.

A novel inhibitor of the insulin/IGF signaling pathway protects from age-onset, neurodegeneration-linked proteotoxicity.

Aging manipulation is an emerging strategy aimed to postpone the manifestation of late-onset neurodegenerative disorders such as Alzheimer's (AD) and Huntington's diseases (HD) and to slow their progression once emerged. Reducing the activity of the insulin/IGF signaling cascade (IIS), a prominent aging-regulating pathway, protects worms from proteotoxicity of various aggregative proteins, including the AD-associated peptide, Aß- and the HD-linked peptide, polyQ40. Similarly, IGF1 signaling reduction protects mice from AD-like disease. These discoveries suggest that IIS inhibitors can serve as new drugs for the treatment of neurodegenerative maladies including AD and HD. Here, we report that NT219, a novel IIS inhibitor, mediates a long-lasting, highly efficient inhibition of this signaling cascade by a dual mechanism; it reduces the autophosphorylation of the IGF1 receptor and directs the insulin receptor substrates 1 and 2 (IRS 1/2) for degradation. NT219 treatment promotes stress resistance and protects nematodes from AD- and HD-associated proteotoxicity without affecting lifespan. Our discoveries strengthen the theme that IIS inhibition has a therapeutic potential as a cure for neurodegenerative maladies and point at NT219 as a promising compound for the treatment of these disorders through a selective manipulation of aging.

Differential regulation of the heat shock factor 1 and DAF-16 by neuronal nhl-1 in the nematode C. elegans.

In the nematode Caenorhabditis elegans, insulin/insulin-like growth factor 1 (IGF-1) signaling (IIS) reduction hyperactivates the transcription factors DAF-16 and heat shock factor 1 (HSF-1), creating long-lived, stress-resistant worms that are protected from proteotoxicity. How DAF-16 executes its distinct functions in response to IIS reduction is largely obscure. Here, we report that NHL-1, a member of the TRIM-NHL protein family, acts in chemosensory neurons to promote stress resistance in distal tissues by DAF-16 activation but is dispensable for the activation of HSF-1. The expression of nhl-1 is regulated by the IIS, defining a neuronal regulatory circuit that controls the organismal stress response. The knockdown of nhl-1 protects nematodes that express the Alzheimer-disease-associated Aß peptide from proteotoxicity but has no effect on lifespan. Our findings indicate that DAF-16- and HSF-1-regulated heat-responsive mechanisms are differentially controlled by neurons and show that one neuronal protein can be involved in the activation of different stress responses in remote tissues.

Insulin receptor signaling mediates APP processing and ß-amyloid accumulation without altering survival in a transgenic mouse model of Alzheimer's disease.

In brains from patients with Alzheimer's disease (AD), expression of insulin receptor (IR), insulin-like growth factor-1 receptor (IGF-1R), and insulin receptor substrate proteins is downregulated. A key step in the pathogenesis of AD is the accumulation of amyloid precursor protein (APP) cleavage products, ß-amyloid (Aß)(1-42) and Aß(1-40). Recently, we and others have shown that central IGF-1 resistance reduces Aß accumulation as well as Aß toxicity and promotes survival. To define the role of IR in this context, we crossed neuron-specific IR knockout mice (nIR(-/-)) with Tg2576 mice, a well-established mouse model of an AD-like pathology. Here, we show that neuronal IR deficiency in Tg2576 (nIR(-/-)Tg2576) mice leads to markedly decreased Aß burden but does not rescue premature mortality of Tg2576 mice. Analyzing APP C-terminal fragments (CTF) revealed decreased α-/ß-CTFs in the brains of nIR(-/-)Tg2576 mice suggesting decreased APP processing. Cell based experiments showed that inhibition of the PI3-kinase pathway suppresses endosomal APP cleavage and decreases α- as well as ß-secretase activity. Deletion of only one copy of the neuronal IGF-1R partially rescues the premature mortality of Tg2576 mice without altering total amyloid load. Analysis of Tg2576 mice expressing either a dominant negative or constitutively active form of forkhead box-O (FoxO)1 did not reveal any alteration of amyloid burden, APP processing and did not rescue premature mortality in these mice. Thus, our findings identified IR signaling as a potent regulator of Aß accumulation in vivo. But exclusively decreased IGF-1R expression reduces AD-associated mortality independent of ß-amyloid accumulation and FoxO1-mediated transcription.

The Role of Insulin and Insulin-Like Growth Factor-1/FoxO-Mediated Transcription for the Pathogenesis of Obesity-Associated Dementia.

Epidemiological studies suggest that being obese in midlife is a risk factor for cognitive decline and dementia in later life. Hyperinsulinemia is one of the most frequent endocrine features in overweight people which results in insulin desensitization. Thus, chronically high insulin levels have been identified as risk factor for dementia. Accordingly, chronically high insulin levels might be harmful for brain function. Furthermore, insulin and IGF-1-induced signaling is reduced in the brains of patients suffering from Alzheimer's disease (AD). Interestingly, studies in rodents suggest that reduced insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF-1R) signaling decrease AD pathology, that is, ß-amyloid toxicity. Data obtained in C. elegans indicate that the beneficial effect mediated via reduced IR/IGF-1R signaling might partially be induced via the forkhead-box O transcription factors (FoxO). In the mammalian brain, there are FoxO1, FoxO3a, and FoxO6 expressed. Surprisingly, high-fat diet specifically reduces the expression of FoxO3a and FoxO6 suggesting that IR/IGF-1 → FoxO-mediated transcription is involved in the pathogenesis of obesity-associated cognitive impairment. Therefore, the function of FoxO1 and FoxO3a has been investigated in animal models of Alzheimer's disease in detail. The current paper focuses on the role of IR/IGF-1 signaling and IR/IGF-1 → FoxO-mediated transcription for the pathogenesis of obesity-associated dementia.

The carboxy-terminal domain of Dictyostelium C-module-binding factor is an independent gene regulatory entity.

The C-module-binding factor (CbfA) is a multidomain protein that belongs to the family of jumonji-type (JmjC) transcription regulators. In the social amoeba Dictyostelium discoideum, CbfA regulates gene expression during the unicellular growth phase and multicellular development. CbfA and a related D. discoideum CbfA-like protein, CbfB, share a paralogous domain arrangement that includes the JmjC domain, presumably a chromatin-remodeling activity, and two zinc finger-like (ZF) motifs. On the other hand, the CbfA and CbfB proteins have completely different carboxy-terminal domains, suggesting that the plasticity of such domains may have contributed to the adaptation of the CbfA-like transcription factors to the rapid genome evolution in the dictyostelid clade. To support this hypothesis we performed DNA microarray and real-time RT-PCR measurements and found that CbfA regulates at least 160 genes during the vegetative growth of D. discoideum cells. Functional annotation of these genes revealed that CbfA predominantly controls the expression of gene products involved in housekeeping functions, such as carbohydrate, purine nucleoside/nucleotide, and amino acid metabolism. The CbfA protein displays two different mechanisms of gene regulation. The expression of one set of CbfA-dependent genes requires at least the JmjC/ZF domain of the CbfA protein and thus may depend on chromatin modulation. Regulation of the larger group of genes, however, does not depend on the entire CbfA protein and requires only the carboxy-terminal domain of CbfA (CbfA-CTD). An AT-hook motif located in CbfA-CTD, which is known to mediate DNA binding to A+T-rich sequences in vitro, contributed to CbfA-CTD-dependent gene regulatory functions in vivo.