Klotho, PTSD, and advanced epigenetic age in cortical tissue.

This study examined the klotho (KL) longevity gene polymorphism rs9315202 and psychopathology, including posttraumatic stress disorder (PTSD), depression, and alcohol-use disorders, in association with advanced epigenetic age in three postmortem cortical tissue regions: dorsolateral and ventromedial prefrontal cortices and motor cortex. Using data from the VA National PTSD Brain Bank (n = 117), we found that rs9315202 interacted with PTSD to predict advanced epigenetic age in motor cortex among the subset of relatively older (>=45 years), white non-Hispanic decedents (corrected p = 0.014, n = 42).

A method to specifically activate the Klotho promoter by using zinc finger proteins constructed from modular building blocks and from naturally engineered Egr1 transcription factor backbone.

There is an unmet need for treatments for diseases associated with aging. The antiaging, life-extending, and cognition-enhancing protein Klotho is neuroprotective due to its anti-inflammatory, antioxidative, and pro-myelinating effects. In addition, Klotho is also a tumor suppressor and has beneficial roles in multiple organs.

Identification of the cleavage sites leading to the shed forms of human and mouse anti-aging and cognition-enhancing protein Klotho.

Klotho is an age-extending, cognition-enhancing protein found to be down-regulated in aged mammals when age-related diseases start to appear. Low levels of Klotho occur in neurodegenerative diseases, kidney disease and many cancers. Many normal and pathologic processes involve the proteolytic shedding of membrane proteins.

Klotho regulation by albuminuria is dependent on ATF3 and endoplasmic reticulum stress.

Proteinuria is associated with renal function decline and cardiovascular mortality. This association may be attributed in part to alterations of Klotho expression induced by albuminuria, yet the underlying mechanisms are unclear. The presence of albumin decreased Klotho expression in the POD-ATTAC mouse model of proteinuric kidney disease as well as in kidney epithelial cell lines.

Klotho Is Neuroprotective in the Superoxide Dismutase (SOD1) Mouse Model of ALS.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the loss of motor neurons in the brain and spinal cord. ALS neuropathology is associated with increased oxidative stress, excitotoxicity, and inflammation. We and others reported that the anti-aging and cognition-enhancing protein Klotho is a neuroprotective, antioxidative, anti-inflammatory, and promyelinating protein.

Small Molecule Amyloid-β Protein Precursor Processing Modulators Lower Amyloid-β Peptide Levels via cKit Signaling.

Alzheimer's disease (AD) is characterized by the accumulation of neurotoxic amyloid-β (Aβ) peptides consisting of 39-43 amino acids, proteolytically derived fragments of the amyloid-β protein precursor (AβPP), and the accumulation of the hyperphosphorylated microtubule-associated protein tau. Inhibiting Aβ production may reduce neurodegeneration and cognitive dysfunction associated with AD. We have previously used an AβPP-firefly luciferase enzyme complementation assay to conduct a high throughput screen of a compound library for inhibitors of AβPP dimerization, and identified a compound that reduces Aβ levels.

Activation of the Anti-Aging and Cognition-Enhancing Gene Klotho by CRISPR-dCas9 Transcriptional Effector Complex.

Multiple lines of evidence show that the anti-aging and cognition-enhancing protein Klotho fosters neuronal survival, increases the anti-oxidative stress defense, and promotes remyelination of demyelinated axons. Thus, upregulation of the Klotho gene can potentially alleviate the symptoms and/or prevent the progression of age-associated neurodegenerative diseases such as Alzheimer's disease and demyelinating diseases such as multiple sclerosis. Here we used a CRISPR-dCas9 complex to investigate single-guide RNA (sgRNA) targeting the Klotho promoter region for efficient transcriptional activation of the Klotho gene.

The Anti-Aging Protein Klotho Enhances Remyelination Following Cuprizone-Induced Demyelination.

The current study examined whether overexpression of Klotho (KL) in transgenic mice can enhance remyelination following cuprizone-induced demyelination and improves the clinical outcome in experimental autoimmune encephalomyelitis (EAE). Demyelination was achieved by feeding transgenic mice overexpressing the transmembrane form of Klotho (KL-OE) and wild-type (WT) littermates cuprizone-containing chow for 6 weeks. The animals were then allowed to remyelinate for 3 weeks.

Identification of cleavage sites leading to the shed form of the anti-aging protein klotho.

Membrane protein shedding is a critical step in many normal and pathological processes. The anti-aging protein klotho (KL), mainly expressed in kidney and brain, is secreted into the serum and CSF, respectively. KL is proteolytically released, or shed, from the cell surface by ADAM10 and ADAM17, which are the α-secretases that also cleave the amyloid precursor protein and other proteins.

PLXNA4 is associated with Alzheimer disease and modulates tau phosphorylation.

Objective: Much of the genetic basis for Alzheimer disease (AD) is unexplained. We sought to identify novel AD loci using a unique family-based approach that can detect robust associations with infrequent variants (minor allele frequency < 0.10).

The neuroprotective effect of Klotho is mediated via regulation of members of the redox system.

Generation of reactive oxygen species (ROS), leading to oxidative damage and neuronal cell death, plays an important role in the pathogenesis of neurodegenerative disorders, including Alzheimer disease. The present study aimed to examine the mechanism by which the anti-aging protein Klotho exerts neuroprotective effects against neuronal damage associated with neurodegeneration and oxidative stress. Pretreatment of rat primary hippocampal neurons and mouse hippocampal neuronal cell line HT22 with recombinant Klotho protected these cells from glutamate and oligomeric amyloid β (oAβ)-induced cytotoxicity.

The anti-aging and tumor suppressor protein Klotho enhances differentiation of a human oligodendrocytic hybrid cell line.

Klotho functions as an aging suppressor, which, in mice, extends lifespan when overexpressed and accelerates development of aging-like phenotypes when disrupted. Klotho is mainly expressed in brain and kidney and is secreted into the serum and CSF. We have previously shown that Klotho is reduced in brains of old monkeys, rats, and mice.

Biochemical and functional characterization of the klotho-VS polymorphism implicated in aging and disease risk.

Klotho (KL) is an age-regulating protein named after the Greek goddess who spins the thread of life. Mice deficient in KL are normal throughout development, but rapidly degenerate and display a variety of aging-associated abnormalities that eventually lead to decreased life expectancy. While multiple genetic association studies have identified KL polymorphisms linked with changes in disease risk, there is a paucity of concrete mechanistic data to explain how these amino acid substitutions alter KL protein function.

Comparable dimerization found in wildtype and familial Alzheimer's disease amyloid precursor protein mutants.

Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder marked by memory impairment and cognitive deficits. A major component of AD pathology is the accumulation of amyloid plaques in the brain, which are comprised of amyloid beta (Aβ) peptides derived from the amyloidogenic processing of the amyloid precursor protein (AβPP) by β- and γ-secretases. In a subset of patients, inheritance of mutations in the AβPP gene is responsible for altering Aβ production, leading to early onset disease.

The antiaging protein Klotho enhances oligodendrocyte maturation and myelination of the CNS.

We have previously shown that myelin abnormalities characterize the normal aging process of the brain and that an age-associated reduction in Klotho is conserved across species. Predominantly generated in brain and kidney, Klotho overexpression extends life span, whereas loss of Klotho accelerates the development of aging-like phenotypes. Although the function of Klotho in brain is unknown, loss of Klotho expression leads to cognitive deficits.

Small-molecule Klotho enhancers as novel treatment of neurodegeneration.

The majority of neurodegenerative diseases have an important age component, and thus, understanding the molecular changes that occur during normal aging of the brain is of utmost relevance. In search for the basis of the age-related cognitive decline found in humans, monkeys and rodents, we study the rhesus monkey. Surprisingly, there is no loss of neurons in aged monkey brains.

Lowering of amyloid beta peptide production with a small molecule inhibitor of amyloid-β precursor protein dimerization.

The amyloid β precursor protein (APP) is a single-pass transmembrane glycoprotein that is ubiquitously expressed in many cell types, including neurons. Amyloidogenic processing of APP by β- and γ-secretases leads to the production of amyloid-β (Aβ) peptides that can oligomerize and aggregate into amyloid plaques, a characteristic hallmark of Alzheimer's disease (AD) brains. Multiple reports suggest that dimerization of APP may play a role in Aβ production; however, it is not yet clear whether APP dimers increase or decrease Aβ and the mechanism is not fully understood.

Identification of novel small molecules that elevate Klotho expression.

The absence of Klotho (KL) from mice causes the development of disorders associated with human aging and decreased longevity, whereas increased expression prolongs lifespan. With age, KL protein levels decrease, and keeping levels consistent may promote healthier aging and be disease-modifying. Using the KL promoter to drive expression of luciferase, we conducted a high-throughput screen to identify compounds that activate KL transcription.

Detection of amyloid-β protein precursor homo-interactions using beta-galactosidase enzyme fragment complementation.

Amyloidogenic processing of the amyloid-β protein precursor (AβPP) produces amyloid-β peptides (Aβ), the major constituent of amyloid plaques in the brains of Alzheimer's disease (AD) patients. Experimental evidence suggests that increased dimerization of AβPP increases Aβ while decreased dimerization of AβPP decreases Aβ production. If true, developing tools for detecting AβPP-AβPP interactions to understand AβPP processing leading to Aβ production would be important.

Cell-type dependent modulation of Notch signaling by the amyloid precursor protein.

The amyloid precursor protein is a ubiquitously expressed transmembrane protein that has been long implicated in the pathogenesis of Alzheimer's disease but its normal biological function has remained elusive despite extensive effort. We have previously reported the identification of Notch2 as an amyloid precursor protein interacting protein in E18 rat neurons. Here, we sought to reveal the physiologic consequences of this interaction.

Oxysterol-binding protein-1 (OSBP1) modulates processing and trafficking of the amyloid precursor protein.

Background: Evidence from biochemical, epidemiological and genetic findings indicates that cholesterol levels are linked to amyloid-beta (Abeta) production and Alzheimer's disease (AD). Oxysterols, which are cholesterol-derived ligands of the liver X receptors (LXRs) and oxysterol binding proteins, strongly regulate the processing of amyloid precursor protein (APP). Although LXRs have been studied extensively, little is known about the biology of oxysterol binding proteins.

Insulin stimulates the cleavage and release of the extracellular domain of Klotho by ADAM10 and ADAM17.

Cleavage and release (shedding) of membrane proteins is a critical regulatory step in many normal and pathological processes. Evidence suggests that the antiaging transmembrane protein Klotho (KL) is shed from the cell surface by proteolytic cleavage. In this study, we attempted to identify the enzymes responsible for the shedding of KL by treating KL-transfected COS-7 cells with a panel of proteinase inhibitors and measuring cleavage products by Western blot.

Age-dependent accumulation of ubiquitinated 2',3'-cyclic nucleotide 3'-phosphodiesterase in myelin lipid rafts.

Changes in brain white matter are prominent features of the aging brain and include glial cell activation, disruption of myelin membranes with resultant reorganization of the molecular components of the node of Ranvier, and loss of myelinated fibers associated with inflammation and oxidative stress. In previous studies, overexpression of CNP, a key myelin protein, was implicated in age-related changes in myelin and axons. Here we examine the extent of CNP accumulation in brain white matter and isolated myelin of aged rhesus monkeys and its relationship to CNP degradation and partitioning in myelin.

Visualization of APP dimerization and APP-Notch2 heterodimerization in living cells using bimolecular fluorescence complementation.

We previously demonstrated that the amyloid precursor protein (APP) interacts with Notch receptors. Here, we confirmed the APP/Notch1 endogenous interaction in embryonic day 17 rat brain tissue, suggesting the interaction was not as a result of over-expression artifacts. To investigate potential homodimeric and heterodimeric interactions of APP and Notch2 (N2), we have visualized the subcellular localization of the APP/N2 complexes formed in living cells using bimolecular fluorescence complementation (BiFC) analysis.

Amyloid precursor protein interacts with notch receptors.

The amyloid precursor protein (APP) must fulfill important roles based on its sequence conservation from fly to human. Although multiple functions for APP have been proposed, the best-known role for this protein is as the precursor of Abeta peptide, a neurotoxic 39-43-amino acid peptide crucial to the pathogenesis of Alzheimer's disease. To investigate additional roles for APP with an eye toward understanding the molecular basis of the pleiotropic effects ascribed to APP, we isolated proteins that interacted with the plasma membrane isoform of APP.