Galactosyl- and glucosylsphingosine induce lysosomal membrane permeabilization and cell death in cancer cells.

Isomeric lysosphingolipids, galactosylsphingosine (GalSph) and glucosylsphingosine (GlcSph), are present in only minute levels in healthy cells. Due to defects in their lysosomal hydrolysis, they accumulate at high levels and cause cytotoxicity in patients with Krabbe and Gaucher diseases, respectively. Here, we show that GalSph and GlcSph induce lysosomal membrane permeabilization, a hallmark of lysosome-dependent cell death, in human breast cancer cells (MCF7) and primary fibroblasts.

Conformational dynamics of free and membrane-bound human Hsp70 in model cytosolic and endo-lysosomal environments.

The binding of the major stress-inducible human 70-kDa heat shock protein (Hsp70) to the anionic phospholipid bis-(monoacylglycero)-phosphate (BMP) in the lysosomal membrane is crucial for its impact on cellular pathology in lysosomal storage disorders. However, the conformational features of this protein-lipid complex remain unclear. Here, we apply hydrogen-deuterium exchange mass spectrometry (HDX-MS) to describe the dynamics of the full-length Hsp70 in the cytosol and its conformational changes upon translocation into lysosomes.

Clinical disease progression and biomarkers in Niemann-Pick disease type C: a prospective cohort study.

Background: Niemann-Pick disease type C (NPC) is a rare, progressive, neurodegenerative disease associated with neurovisceral manifestations resulting from lysosomal dysfunction and aberrant lipid accumulation. A multicentre, prospective observational study (Clinical Trials.gov ID: NCT02435030) of individuals with genetically confirmed NPC1 or NPC2 receiving routine clinical care was conducted, to prospectively characterize and measure NPC disease progression and to investigate potential NPC-related biomarkers versus healthy individuals.

Cerebrospinal fluid oxidative stress metabolites in patients with bipolar disorder and healthy controls: a longitudinal case-control study.

Bipolar disorder (BD) is a mental disorder characterized by recurrent relapses of affective episodes, cognitive impairment, illness progression, and reduced life expectancy. Increased systemic oxidatively generated nucleoside damage have been found in some neurodegenerative disorders and in BD. As the first, this naturalistic prospective, longitudinal follow-up case-control study investigated cerebrospinal fluid (CSF) oxidative stress markers 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) that relate to RNA and DNA damage, respectively.

HSP70 induces liver X receptor pathway activation and cholesterol reduction in vitro and in vivo.

Objective: Heat Shock Proteins (HSPs) maintain cellular homeostasis under stress. HSP70 represents a major stress-inducible family member and has been identified as a druggable target in inherited cholesterol-sphingolipid storage diseases. We investigated if HSP70 modulates cholesterol accumulation in more common conditions related to atherogenesis.

Animal models for Niemann-Pick type C: implications for drug discovery & development.

Niemann-Pick type C (NPC) is a neurovisceral, progressively detrimental lysosomal storage disease with very limited therapeutic options and no approved treatment available in the US. Despite its rarity, NPC has seen increased drug developmental efforts over the past decade, culminating in the completion of two potential registration trials in 2018. Areas covered: This review highlights the many available animal models that have been developed in the field and briefly covers classical and new cell technologies.

Annual severity increment score as a tool for stratifying patients with Niemann-Pick disease type C and for recruitment to clinical trials.

Background: Niemann-Pick disease type C (NPC) is a lysosomal storage disease with a heterogeneous neurodegenerative clinical course. Multiple therapies are in clinical trials and inclusion criteria are currently mainly based on age and neurological signs, not taking into consideration differential individual rates of disease progression.

Results: In this study, we have evaluated a simple metric, denoted annual severity increment score (ASIS), that measures rate of disease progression and could easily be used in clinical practice.

Differences in clinical presentation between bipolar I and II disorders in the early stages of bipolar disorder: A naturalistic study.

Aim: In a naturalistic clinical study of patients in the early stages of bipolar disorders the aim was to assess differences between patients with bipolar I (BD I) and bipolar II (BD II) disorders on clinical characteristics including affective symptoms, subjective cognitive complaints, functional level, the presence of comorbid personality disorders and coping strategies.

Methods: Diagnoses were confirmed using the Structured Clinical Interview for DSM-IV Disorders. Clinical symptoms were rated with the Young Mania Rating Scale and the Hamilton Depression Rating Scale, and functional status using the Functional Assessment Short Test.

Accuracy of abdominal auscultation for bowel obstruction.

Aim: To investigate the accuracy and inter-observer variation of bowel sound assessment in patients with clinically suspected bowel obstruction.

Methods: Bowel sounds were recorded in patients with suspected bowel obstruction using a Littmann(®) Electronic Stethoscope. The recordings were processed to yield 25-s sound sequences in random order on PCs.

Lysosomal storage diseases and the heat shock response: convergences and therapeutic opportunities.

Lysosomes play a vital role in the maintenance of cellular homeostasis through the recycling of cell constituents, a key metabolic function which is highly dependent on the correct function of the lysosomal hydrolases and membrane proteins, as well as correct membrane lipid stoichiometry and composition. The critical role of lysosomal functionality is evident from the severity of the diseases in which the primary lesion is a genetically defined loss-of-function of lysosomal hydrolases or membrane proteins. This group of diseases, known as lysosomal storage diseases (LSDs), number more than 50 and are associated with severe neurodegeneration, systemic disease, and early death, with only a handful of the diseases having a therapeutic option.

Human heat shock protein 70 (Hsp70) as a peripheral membrane protein.

While a significant fraction of heat shock protein 70 (Hsp70) is membrane associated in lysosomes, mitochondria, and the outer surface of cancer cells, the mechanisms of interaction have remained elusive, with no conclusive demonstration of a protein receptor. Hsp70 contains two Trps, W90 and W580, in its N-terminal nucleotide binding domain (NBD), and the C-terminal substrate binding domain (SBD), respectively. Our fluorescence spectroscopy study using Hsp70 and its W90F and W580F mutants, and Hsp70-∆SBD and Hsp70-∆NBD constructs, revealed that binding to liposomes depends on their lipid composition and involves both NBD and SBD.

Effects of a screening and treatment protocol with haloperidol on post-cardiotomy delirium: a prospective cohort study.

Objectives: Post-cardiotomy delirium is common and associated with increased morbidity and mortality. No gold standard exists for detecting delirium, and evidence to support the choice of treatment is needed. Haloperidol is widely used for treating delirium, but indication, doses and therapeutic targets vary.

Transformation-associated changes in sphingolipid metabolism sensitize cells to lysosomal cell death induced by inhibitors of acid sphingomyelinase.

Lysosomal membrane permeabilization and subsequent cell death may prove useful in cancer treatment, provided that cancer cell lysosomes can be specifically targeted. Here, we identify acid sphingomyelinase (ASM) inhibition as a selective means to destabilize cancer cell lysosomes. Lysosome-destabilizing experimental anticancer agent siramesine inhibits ASM by interfering with the binding of ASM to its essential lysosomal cofactor, bis(monoacylglycero)phosphate.

Sunitinib and SU11652 inhibit acid sphingomyelinase, destabilize lysosomes, and inhibit multidrug resistance.

Defective apoptosis signaling and multidrug resistance are major barriers for successful cancer treatment. To identify drugs capable of targeting treatment-resistant cancer cells, we screened small-molecule kinase inhibitor libraries for compounds that decrease the viability of apoptosis-resistant human MCF7-Bcl-2 breast cancer cells. SU11652, a multitargeting receptor tyrosine kinase inhibitor, emerged as the most potent compound in the screen.

Identification of autophagosome-associated proteins and regulators by quantitative proteomic analysis and genetic screens.

Autophagy is one of the major intracellular catabolic pathways, but little is known about the composition of autophagosomes. To study the associated proteins, we isolated autophagosomes from human breast cancer cells using two different biochemical methods and three stimulus types: amino acid deprivation or rapamycin or concanamycin A treatment. The autophagosome-associated proteins were dependent on stimulus, but a core set of proteins was stimulus-independent.

Activation of phospholipase A2 by Hsp70 in vitro.

We recently suggested a novel mechanism for the activation of phospholipase A2 (PLA2), with a (catalytically) highly active oligomeric state, which subsequently becomes inactivated by conversion into amyloid. This process can be activated by lysophosphatidylcholine which promotes both oligomerization and amyloid activation/inactivation. The heat shock protein 70 (Hsp70), has been demonstrated to be able to revert the conversion of α-synuclein and Alzheimer β-peptide to amyloid fibrils in vitro.

HSP70 and lysosomal storage disorders: novel therapeutic opportunities.

Lysosomes, with their arsenal of catabolic enzymes and crucial metabolic housekeeping functions are experiencing a revived research interest after having lived a rather quiet life for the last few decades. With the discovery of the interaction of the lysosomes with another ancient component of cellular homoeostasis, the molecular chaperone HSP70 (heat-shock protein 70), the stage seems set for further discoveries of the mechanisms regulating cellular and physiological stress responses to otherwise detrimental challenges.

Connecting Hsp70, sphingolipid metabolism and lysosomal stability.

Heat shock protein 70 (Hsp70) is an evolutionary highly conserved molecular chaperone. Upon cancer-associated translocation to the lysosomal compartment, it promotes cell survival by inhibiting lysosomal membrane permeabilization, a hallmark of stress-induced death. We have recently shown that Hsp70 stabilizes lysosomes by binding to the endo-lysosomal lipid bis(monoacylglycero)phosphate (BMP), an essential co-factor for lysosomal sphingolipid catabolism.

Hsp70 stabilizes lysosomes and reverts Niemann-Pick disease-associated lysosomal pathology.

Heat shock protein 70 (Hsp70) is an evolutionarily highly conserved molecular chaperone that promotes the survival of stressed cells by inhibiting lysosomal membrane permeabilization, a hallmark of stress-induced cell death. Clues to its molecular mechanism of action may lay in the recently reported stress- and cancer-associated translocation of a small portion of Hsp70 to the lysosomal compartment. Here we show that Hsp70 stabilizes lysosomes by binding to an endolysosomal anionic phospholipid bis(monoacylglycero)phosphate (BMP), an essential co-factor for lysosomal sphingomyelin metabolism.

BAMLET activates a lysosomal cell death program in cancer cells.

A complex of human alpha-lactalbumin and oleic acid (HAMLET) was originally isolated from human milk as a potent anticancer agent. It kills a wide range of transformed cells of various origins while leaving nontransformed healthy cells largely unaffected both in vitro and in vivo. Importantly, purified alpha-lactalbumins from other mammals form complexes with oleic acid that show biological activities similar to that of HAMLET.