Acid Lipase Research Articles

Screening for lysosomal acid lipase deficiency in Japanese patients with suspected familial hypercholesterolemia

Screening for lysosomal acid lipase deficiency in Japanese patients with suspected familial hypercholesterolemia

Cryptogenic chronic hepatitis: looking for an ideal diagnostic algorithm

IntroductionCryptogenic chronic hepatitis is a growing cause of liver transplants, affecting 5%–15% of patients with chronic liver diseases. This study aimed to identify underlying causes of cryptogenic liver disease in a Brazilian cohort and propose a new diagnostic algorithm, including investigation for metabolic-dysfunction-associated fatty liver disease (MAFLD) and lysosomal acid lipase deficiency (LAL-D).MethodsA retrospective analysis was conducted on 326 patients with presumed cryptogenic hepatitis.ResultsUsing Czaja’s algorithm, non-alcoholic fatty liver disease was diagnosed in 21.3% of patients, while alpha-1 antitrypsin deficiency, alcoholic liver disease, autoimmune hepatitis, hemochromatosis, biliary-related hepatitis, viral hepatitis, Budd–Chiari syndrome, glycogenosis, drug-induced liver injury, and Wilson’s disease were diagnosed in smaller proportions (< 3.5% each). LAL-D was found in 1% of patients, and 53.6% of patients remained with cryptogenic hepatitis. The etiology of the liver disease in a subset of patients undergoing liver transplantation was updated post hoc based on explant histology, and non-alcoholic steatohepatitis was found in 52.5% of patients. By incorporating the concept of MAFLD, the new algorithm could diagnose 49.1% of patients, reducing the number of individuals without an etiological diagnosis by 11.4%.ConclusionOne-third of patients with initially presumed cryptogenic liver disease were diagnosed with MAFLD. LAL-D should be considered in patients with chronic liver disease of unknown etiology. The updated diagnostic algorithm proposed in this study could improve diagnostic accuracy and aid in the management of patients with cryptogenic hepatitis.

First LIPA Mutational Analysis in Egyptian Patients Reveals One Novel Variant: Wolman Disease

Lysosomal acid lipase (LAL) is a necessary enzyme for the hydrolysis of both triglycerides (TGs) and cholesteryl esters (CEs) in the lysosome. Deficiency of this enzyme encoded by the lipase A (LIPA) gene leads to LAL deficiency (LAL-D). A severe disease subtype of LAL-D is known as Wolman disease (WD), present with diarrhea, hepatosplenomegaly, and adrenal calcification. Untreated patients do not survive more than a year. The aim of this study was to assess the clinical and molecular characterizations of WD patients in Egypt. A total of seven patients (from five unrelated Egyptian families) were screened by targeted next-generation sequencing (NGS), and the co-segregation of causative variants was analyzed using Sanger sequencing. Furthermore, multiple in silico analyses were performed to assess the pathogenicity of the candidate variants. Overall, we identified three diseases causing variants harbored in the LIPA gene. One of these variants is a novel missense variant (NM_000235.4: c.1122 T > G; p. His374Gln), which was classified as a likely pathogenic variant. All variants were predicted to be disease causing using in silico analyses. Our findings expand the spectrum of variants involved in WD which may help to investigate phenotype-genotype correlation and assist genetic counseling. To the best of our knowledge, this is the first clinico-genetic study carried out on Egyptian patients affected with WD.

Complete degradation of di-n-butyl phthalate by Glutamicibacter sp. strain 0426 with a novel pathway.

Di-n-butyl phthalate (DBP) is widely used as plasticizer that has potential carcinogenic, teratogenic, and endocrine effects. In the present study, an efficient DBP-degrading bacterial strain 0426 was isolated and identified as a Glutamicibacter sp. strain 0426. It can utilize DBP as the sole source of carbon and energy and completely degraded 300mg/L of DBP within 12h. The optimal conditions (pH 6.9 and 31.7°C) for DBP degradation were determined by response surface methodology and DBP degradation well fitted with the first-order kinetics. Bioaugmentation of contaminated soil with strain 0426 enhanced DBP (1mg/g soil) degradation, indicating the application potential of strain 0426 for environment DBP removal. Strain 0426 harbors a distinctive DBP hydrolysis mechanism with two parallel benzoate metabolic pathways, which may account for the remarkable performance of DBP degradation. Sequences alignment has shown that an alpha/beta fold hydrolase (WP_083586847.1) contained a conserved catalytic triad and pentapeptide motif (GX1SX2G), of which function is similar to phthalic acid ester (PAEs) hydrolases and lipases that can efficiently catalyze hydrolysis of water-insoluble substrates. Furthermore, phthalic acid was converted to benzoate by decarboxylation, which entered into two different pathways: one is the protocatechuic acid pathway under the role of pca cluster, and the other is the catechol pathway. This study demonstrates a novel DBP degradation pathway, which broadens our understanding of the mechanisms of PAE biodegradation.

Oxidative stress induces lysosomal membrane permeabilization and ceramide accumulation in retinal pigment epithelial cells.

Oxidative stress has been implicated in the pathogenesis of age-related macular degeneration, the leading cause of blindness in older adults, with retinal pigment epithelium (RPE) cells playing a key role. To better understand the cytotoxic mechanisms underlying oxidative stress, we used cell culture and mouse models of iron overload, as iron can catalyze reactive oxygen species formation in the RPE. Iron-loading of cultured induced pluripotent stem cell-derived RPE cells increased lysosomal abundance, impaired proteolysis and reduced the activity of a subset of lysosomal enzymes, including lysosomal acid lipase (LIPA) and acid sphingomyelinase (SMPD1). In a liver-specific Hepc (Hamp) knockout murine model of systemic iron overload, RPE cells accumulated lipid peroxidation adducts and lysosomes, developed progressive hypertrophy and underwent cell death. Proteomic and lipidomic analyses revealed accumulation of lysosomal proteins, ceramide biosynthetic enzymes and ceramides. The proteolytic enzyme cathepsin D (CTSD) had impaired maturation. A large proportion of lysosomes were galectin-3 (Lgals3) positive, suggesting cytotoxic lysosomal membrane permeabilization. Collectively, these results demonstrate that iron overload induces lysosomal accumulation and impairs lysosomal function, likely due to iron-induced lipid peroxides that can inhibit lysosomal enzymes.

78-OR: Adipose Lysosomal Acid Lipase Is Indispensable for Starvation- and Cold-Induced Lipolysis

Lipolysis is a metabolic process by which triglycerides (TGs) are hydrolyzed into free fatty acids (FFAs) and glycerol to serve as fuels during fasting or cold-induced nonshivering thermogenesis. Cytoplasmic lipases are thought to be the predominant mechanism of liberating FFA from lipid stores. However, lysosomes also contain lipolytic activity via lysosomal acid lipase (Lipa). In adipocytes, the primary lipid-storing cell in the body with significant involvement in metabolism, the roles of Lipa and lysosomal lipolysis are unclear. We found that Lipa expression increases in the adipose tissue of mice in response to fasting, cold exposure, and CL316,243 (CL) treatment, a mimic of cold-induced lipolysis. Similar results were obtained in cultured adipocytes with nutrient-depletion or isoproterenol treatment, mimicking fasting or cold, respectively. Treatment of C57BL/6J mice with Lalistat (Lali), a specific inhibitor of Lipa, impaired thermogenesis, as evidenced by suppression of cold- and fasting-enhanced increases in plasma FFAs levels during cold exposure or CL treatment. Lipolysis was inhibited by Lali treatment in cultured adipocytes and fresh adipose tissue of C57BL/6J mice under fasting- or cold-mimic conditions. To conduct more detailed in vivo studies, we developed adipose-specific Lipa knockout (A-Lipa) mice, which exhibited lower plasma FFAs when challenged with fasting, cold exposure, or CL treatment. Furthermore, A-Lipa mice were significantly thermogenesis-impaired with exposure to cold or treatment with CL. To determine whether autophagy is involved in these phenomena, adipose-specific Atg5 knockout (A-Atg5) mice were challenged with fasting, cold exposure, or CL treatment. As was found in A-Lipa mice, A-Atg5 mice had lower levels of plasma FFAs and obliteration of stress-induced thermogenesis. Overall, our data suggest a previously unrecognized contribution of lysosomal lipolysis in adipocytes, possibly involving autophagy-related lipophagy. Disclosure Y.Yeh: None. B.Razani: None. Funding American Heart Association (897628); National Institutes of Health (DK131188)

Recent insights into lysosomal acid lipase deficiency

Lysosomal acid lipase (LAL) is the sole enzyme known to degrade neutral lipids in the lysosome. Mutations in the LAL-encoding LIPA gene lead to rare lysosomal lipid storage disorders with complete or partial absence of LAL activity. This review discusses the consequences of defective LAL-mediated lipid hydrolysis on cellular lipid homeostasis, epidemiology, and clinical presentation. Early detection of LAL deficiency (LAL-D) is essential for disease management and survival. LAL-D must be considered in patients with dyslipidemia and elevated aminotransferase concentrations of unknown etiology. Enzyme replacement therapy, sometimes in combination with hematopoietic stem cell transplantation (HSCT), is currently the only therapy for LAL-D. New technologies based on mRNA and viral vector gene transfer are recent efforts to provide other effective therapeutic strategies.

Lysosomal acid lipase deficiency manifestations in children and adults: Baseline data from an international registry.

Lysosomal acid lipase deficiency (LAL-D) is a rare, autosomal recessive disease involving lysosomal accumulation of cholesteryl esters and triglycerides. The International Lysosomal Acid Lipase Deficiency Registry (NCT01633489), established in 2013 to understand LAL-D natural history and long-term outcomes, is accessible to centres caring for patients diagnosed by deficient LAL activity and/or biallelic pathogenic LIPA variants. We describe the registry population enrolled through 2 May 2022. In this prospective observational study, we analysed demographic and baseline clinical characteristics of children (ages ≥6 months to <18 years) and adults diagnosed with LAL-D. Of 228 patients with confirmed disease, 61% were children; 202/220 (92%) with data on race were white. Median age was 5.5 years at sign/symptom onset and 10.5 years at diagnosis; median time from sign/symptom onset to diagnostic testing was 3.3 years. The most common manifestations raising suspicion of disease were elevated alanine (70%) and aspartate aminotransferase levels (67%) and hepatomegaly (63%). Among 157 with reported LIPA mutations, 70 were homozygous and 45 were compound heterozygous for the common exon 8 splice junction pathogenic variant (E8SJM-1). Seventy percent (159/228) of patients had dyslipidaemia. Among 118 with liver biopsies, 63% had microvesicular steatosis exclusively, 23% had mixed micro- and macrovesicular steatosis and 47% had lobular inflammation. Of 78 patients with fibrosis-stage data, 37% had bridging fibrosis and 14% had cirrhosis. Although LAL-D signs/symptoms occur early, diagnosis is often delayed. Abnormal transaminase levels associated with hepatomegaly and dyslipidaemia should raise suspicion and prompt earlier diagnosis of LAL-D. NCT01633489.

Impact of (intestinal) LAL deficiency on lipid metabolism and macrophage infiltration

ObjectiveTo date, the only enzyme known to be responsible for the hydrolysis of cholesteryl esters and triacylglycerols in the lysosome at acidic pH is lysosomal acid lipase (LAL). Lipid malabsorption in the small intestine (SI), accompanied by macrophage infiltration, is one of the most common pathological features of LAL deficiency. However, the exact role of LAL in intestinal lipid metabolism is still unknown. MethodsWe collected three parts of the SI (duodenum, jejunum, ileum) from mice with a global (LAL KO) or intestine-specific deletion of LAL (iLAL KO) and corresponding controls. ResultsWe observed infiltration of lipid-associated macrophages into the lamina propria, where neutral lipids accumulate massively in the SI of LAL KO mice. In addition, LAL KO mice absorb less dietary lipids but have accelerated basolateral lipid uptake, secrete fewer chylomicrons, and have increased fecal lipid loss. Inflammatory markers and genes involved in lipid metabolism were overexpressed in the duodenum of old but not in younger LAL KO mice. Despite the significant reduction of LAL activity in enterocytes of enterocyte-specific (iLAL) KO mice, villous morphology, intestinal lipid concentrations, expression of lipid transporters and inflammatory genes, as well as lipoprotein secretion were comparable to control mice. ConclusionsWe conclude that loss of LAL only in enterocytes is insufficient to cause lipid deposition in the SI, suggesting that infiltrating macrophages are the key players in this process.

Abstract 370: Corticosterone-mediated Associations Between Neighborhood Environment Perceptions and Lysosomal Acid Lipase Levels - Data From The Washington, D.C. Cardiovascular Health and Needs Assessment

Experiences of adverse social determinants of health (SDoH), like less favorable neighborhood environment perceptions, are associated with cardiovascular disease (CVD). Lysosomal acid lipase (LAL) plays an important role in lipid metabolism, and genetic LAL deficiency has been linked to CVD risk. We aimed to determine the potential relationship between neighborhood perceptions and LAL and to evaluate stress-related biomarkers as mediators of this relationship in the D.C. Cardiovascular Health and Needs Assessment cohort (60 African American participants, mean age 61yr, 93% female), biomarkers were measured using ELISA, and perceptions of neighborhood violence, physical and social environment, social cohesion, and safety were determined using validated questionnaires with higher scores indicating more favorable perceptions. We explored neighborhood perceptions-LAL relationships with regression models adjusted for BMI and ASCVD risk score and stratified by hyperlipidemia due to the potential confounding role of LDL. Mediation analysis was used to evaluate cortisol and corticosterone as potential mediators of the neighborhood perceptions-LAL relationship. Of the neighborhood perceptions measured, more favorable perceptions of physical and social environment associated with greater LAL (β=0.23, p=0.09); this association persisted only among participants without hyperlipidemia (β=0.42, p=0.04). Only corticosterone associated with both perceived physical and social environment and LAL (Figure); corticosterone mediated 73.1% of this relationship in all participants and 89.9% of this relationship in participants without hyperlipidemia. Our data highlight the relationship between perceived physical and social environment and LAL mediated by corticosterone. Results also emphasize the importance of future interdisciplinary work to better understand mechanisms by which SDoH and associated biomarkers contribute to CVD disparities.

Lysosomal acid lipase regulates bioenergetic process during the cytodifferentiation of human periodontal ligament cells

Lipid metabolism is one of energy metabolic pathways that produce adenosine triphosphate (ATP). In this pathway, lysosomal acid lipase (LAL) encoded by Lipase A (LIPA), plays an important role in catalyzing lipids to fatty acids (FAs), which drive oxidative phosphorylation (OXPHOS) and generate ATP. Previously, we found that a LIPA single nucleotide polymorphism rs143793106, which decreases the LAL activity, suppressed the cytodifferentiation of human periodontal ligament (HPDL) cells. However, the mechanisms underlying that suppression are still not fully clarified. Thus, we aimed to investigate the mechanisms regulating the cytodifferentiation of HPDL cells by LAL in terms of energy metabolism. We performed the osteogenic induction of HPDL cells with or without Lalistat-2, a LAL inhibitor. To visualize lipid droplet (LD) utilization, we performed confocal microscopy on HPDL cells. We also performed real-time PCR to analyze the gene expression of calcification-related and metabolism-related genes. Furthermore, we measured the ATP production rate from two major energy production pathways, OXPHOS and glycolysis, and OXPHOS-related parameters of HPDL cells during their cytodifferentiation. We found that LDs were utilized during the cytodifferentiation of HPDL cells. Alkaline phosphatase (ALPL), collagen type 1 alpha 1 chain (COL1A1), ATP synthase F1 subunit alpha (ATP5F1A), and carnitine palmitoyltransferase 1A (CPT1A) mRNA expressions were upregulated, whereas lactate dehydrogenase A (LDHA) mRNA expression was downregulated. Additionally, total ATP production rate was significantly increased. In contrast, in the presence of Lalistat-2, LD utilization was inhibited and ALPL, COL1A1, and ATP5F1A mRNA expression was downregulated. Additionally, ATP production rate and spare respiratory capacity of the OXPHOS pathway were decreased in HPDL cells during their cytodifferentiation. Collectively, the defect of LAL in HPDL cells decreased LD utilization and OXPHOS capacity, resulting in reduced energy to sustain the adequate ATP production required for the cytodifferentiation of HPDL cells. Thus, LAL is important for periodontal tissue homeostasis as a regulator of bioenergetic process of HPDL cells.

Evaluation of biochemical profile and oxidative damage to lipids and proteins in patients with lysosomal acid lipase deficiency.

Lysosomal acid lipase deficiency (LALD) is an inborn error of metabolism that lacks satisfactory treatment, which leads to the development of severe hepatic and cardiac complications and may even lead to death. In this sense, knowledge of the mechanisms involved in the pathophysiology of this disorder becomes essential to allow the search for new therapeutic strategies. There are no studies in the literature investigating the role of reactive species and inflammatory processes in the pathophysiology of this disorder. Therefore, the aim of this work was to investigate parameters of oxidative and inflammatory stress in LALD patients. In this work, we obtained results that demonstrate that LALD patients are susceptible to oxidative stress caused by an increase in the production of free radicals, observed by the increase of 2-7-dihydrodichlorofluorescein. The decrease in sulfhydryl content reflects oxidative damage to proteins, as well as a decrease in antioxidant defenses. Likewise, the increase in urinary levels of di-tyrosine observed also demonstrates oxidative damage to proteins. Furthermore, the determination of chitotriosidase activity in the plasma of patients with LALD was significantly higher, suggesting a pro-inflammatory state. An increase in plasma oxysterol levels was observed in patients with LALD, indicating an important relationship between this disease and cholesterol metabolism and oxidative stress. Also, we observed in LALD patients increased levels of nitrate production. The positive correlation found between oxysterol levels and activity of chitotriosidase in these patients indicates a possible link between the production of reactive species and inflammation. In addition, an increase in lipid profile biomarkers such as total and low-density lipoprotein cholesterol were demonstrated in the patients, which reinforces the involvement of cholesterol metabolism. Thus, we can assume that, in LALD, oxidative and nitrosative damage, in addition to inflammatory process, play an important role in its evolution and future clinical manifestations. In this way, we can suggest that the study of the potential benefit of the use of antioxidant and anti-inflammatory substances as an adjuvant tool in the treatment will be important, which should be associated with the already recommended therapy.

Bran from composite grain mixture as an object of deep processing. Part 2. Carbohydrate-amylase and lipid complexes

Polycomponent bran obtained by joint grinding of a grain mixture from cereals (wheat), legumes (lentils) and oilseeds (flax) should be considered as a valuable secondary raw material, the use of which for deep processing will make it possible to obtain various food and feed ingredients. An assessment of the carbohydrate-amylase and lipid complexes of the three variants of multicomponent bran showed that the ratio of amylose and amylopectin in the starch of three-component bran is almost the same, however, in lentil-flax bran, the proportion of amylose is 1.6 times higher than in the first two variants. The specific activity of amylases in three-component bran is about 2 times higher than in lentil-flax bran. In addition, the latter are characterized by a higher content of reducing sugars and fiber. The molecular weight of amylases isolated from three-component bran, according to gel chromatography, was: α-amylase — 40,000 Da; β-amylase — 60,000 Da. It has been established that the addition of flax seeds to the grinding mixture significantly increases the fat content in bran 6.4; 6.0 and 12.9%. The fatty acid composition of the studied bristles is characterized by the predominance of unsaturated fatty acids. At the same time, the ratio of essential acids — linoleic acid (ɷ‑6) to α-linolenic acid (ɷ‑3) in favor of the most deficient α-linolenic acid — was typical for lentil-flax bran and amounted to 1:4.2. The activity of alkaline lipases, which exhibit their effect at pH 8.0 (mainly cereal lipases), and acid lipases (mainly oilseed lipases) with an optimum of action at pH 4.7 in three-component bran samples are approximately the same, and lentil-flax bran is characterized by a high specific acid lipase activity, which is approximately 4.2 times higher than the activity of acid lipases of three-component bran. The data obtained, along with data on the characteristics of the protein-proteinase complex of the studied types of bran, will be used in the development of methods for enzymatic modification (deep processing) and in the preparation of components for the creation of new food products with increased nutritional and biological value.

Ultrasensitive Quantification Method for Understanding Biologically Relevant Concentrations of Host Cell Proteins in Therapeutics.

Certain host cell proteins (HCPs) in biotherapeutic drugs may be detrimental to drug product quality even when they are present at the subppm level. Therefore, an analytical method that can reliably quantify trace amounts of HCPs is desirable. This study demonstrates a novel strategy to quantify HCPs present at subppm levels with ProteoMiner enrichment coupled with limited digestion followed by targeted analysis with nano-liquid chromatography-parallel reaction monitoring. The method can achieve LLOQ values as low as 0.06 ppm, with an accuracy of 85%-111% of the theoretical value, and inter-run and intrarun precision within 12% and 25%, respectively. The approach was applied to the quantification of five high-risk HCPs in drug products. The results indicated that 2.5 ppm lysosomal acid lipase, 0.14 ppm liver carboxylesterase, 1.8 ppm palmitoyl-protein thioesterase 1, and 1 ppm cathepsin D affected the stability of drug products, whereas drug products could safely contain 1.5 ppm lipoprotein lipase, 0.1 ppm lysosomal acid lipase, or 0.3 ppm cathepsin D. In combination with lipase activity analysis, the accurate quantification of lipases/esterases in drug products enables better understanding and comparison of the enzymatic activity of polysorbate degradation from endogenous proteins.

An Unusual Case of Hemophagocytic Lymphohistiocytosis Associated with Mycobacterium chimaera or Large-Cell Neuroendocrine Carcinoma

Hemophagocytic lymphohistiocytosis (HLH) is a rare and very dangerous condition characterized by abnormal activation of the immune system, causing hemophagocytosis, inflammation, and potentially widespread organ damage. The primary (genetic) form, caused by mutations affecting lymphocyte cytotoxicity, is most commonly seen in children. Secondary HLH is commonly associated with infections, malignancies, and rheumatologic disorders. Most current information on diagnosis and treatment is based on pediatric populations. HLH is a disease that should be diagnosed and treated promptly, otherwise it is fatal. Treatment is directed at treating the triggering disorder, along with symptomatic treatment with dexamethasone and etoposide. We present a 56-year-old patient who was admitted with worsening weakness, exertional dyspnea, dry and nonproductive cough, and a 5-pound weight loss associated with loss of appetite. This is among the rare disorders that are not commonly encountered in day-to-day practice. Our differential diagnoses were broad, including infection, such as visceral leishmaniasis, atypical/tuberculous mycobacteria, histoplasmosis, Ehrlichia, Bartonella, Brucella, Adenovirus, disseminated herpes simplex virus (HSV), hematological-like Langerhans cell histiocytosis, or multicentric Castleman disease; drug reaction, such as drug rash with eosinophilia and systemic symptoms (DRESS); and metabolic disorder, including Wolman's disease (infantile lysosomal acid lipase deficiency) or Gaucher's disease. Based on our investigations as described in our case report, it was narrowed down to hemophagocytic lymphohistiocytosis and COVID-19. Two COVID-19 tests were negative. His lab abnormalities and diagnostic testing revealed hemophagocytic lymphohistiocytosis. He was empirically started on antibiotics and dexamethasone, to be continued for 2 weeks then tapered if the patient showed continued improvement. Dexamethasone was tapered over 8 weeks. He improved on just one of the Food and Drug Administration (FDA)-approved medications, proving that treatment should be tailored to the patient. In addition, in this case study, we included the background, etiology, pathogenesis, diagnosis, management, and prognosis of HLH.

Current approaches to the diagnosis and treatment of lysosomal acid lipase deficiency

Lysosomal acid lipase deficiency is a chronic hereditary degenerative disease, substantially worsening quality of life and leading to lethal outcome. The condition is caused by a mutation of the LIPA gene, that is encoding lysosomal acid lipase, resulting in build-up of cholesterol esters and triglycerides. Clinical-pattern is quite variable: from rapidly worsening lethal infant form and severe infant cases with cirrhosis and liver dysfunction in adolescents to subclinical, mostly asymptomatic forms, manifesting in adults. Thus, major part of patients remains unexamined and the pathology itself undiagnosed, so the real incidence is unclear. This article describes clinical case of the diagnostics of lysosomal acid lipase deficiency in RNO-Alania. Efficiency and safety of enzyme substitution treatment is shown.

Abstract P6-10-14: Lysosomal acid lipase (LIPA) as a novel therapeutic vulnerability for treating TNBC

Abstract Background: TNBCs have the highest mortality rate among all BC subtypes. There is thus an urgent and unmet need for effective targeted therapies in TNBC. Recently we, identified a novel agent ERX-41 that showed good efficacy in treating TNBC in preclinical mouse models, however, its molecular action remain unknown. In this study, we identified LIPA as novel molecular target of ERX-41. Methods: We have used CRISPR knockout pooled library and multiple TNBC models for identifying molecular target of ERX-41. Mechanistic studies were performed using LIPA mutants, RNA-seq, Turbo-ID mapping, Mass spectrometry, Immunoprecipitation, and Western blotting. The in vivo efficacy of ERX-41 was examined using four different patient-derived xenograft (PDX) models. We evaluated LIPA protein expression in TNBC using tissue microarray (TMA). Results: To identify the molecular target of ERX-41, we performed an unbiased CRISPR–Cas9 knockout (KO) screen in MDA-MB-231 cells and the results identified LIPA as a top hit. KO of LIPA alone (which encodes lysosomal acid lipase (LAL) abrogated cytotoxic response to ERX-41. Cellular thermal shift assays confirmed that ERX-41 binds to LAL. In silico modelling and mutational studies confirmed that ERX-41 interacts with LAL through residues in its LXXLL domain and that ERX-41 ability to induce ER stress and cell death in TNBC is independent of the lipase activity of LAL. Unbiased RNA-seq studies with and without ERX-41 in parental and LIPA KO SUM-159 cells revealed induction of genes involved in ER stress and UPR response by ERX-41 in parental SUM-159 cells but not in cells with LIPA KO. Ultrastructural studies using live-cell confocal microscopy show that LIPA KO abrogated ER morphological changes at 2 and 4 h after ERX-41 treatment. Further, subcellular localization studies showed LIPA localizes to endoplasmic reticulum (ER). Unbiased proteomic approaches (TurboID and DIA mass spec) identified a core set of proteins that were both LAL binders and affected by ERX-41 treatment. GO analyses of LAL binding proteins confirmed their involvement in protein folding. Tumor micro array (TMA) analyses confirmed that &amp;gt;80% of primary TNBC tumors had significant and detectable LAL protein expression in contrast, normal breast tissue had lower LAL expression. ERX-41 (10 mg/kg body weight) decreased growth of four distinct TNBC patient-derived xenografts (PDXs) in vivo. Conclusions: Our results identified a new molecular target (LAL) for ERX-41 and novel mechanism of action (disruption of protein folding and induction of ER stress) that may have utility in treating patients with TNBC. Citation Format: Suryavathi Viswanadhapalli, Xihui Liu, Uday Pratap, Gangadhara R. Sareddy, Susan T. Weintraub, Ganesh V. Raj, Jung-Mo Ahn, Ratna K. Vadlamudi. Lysosomal acid lipase (LIPA) as a novel therapeutic vulnerability for treating TNBC [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-10-14.

LAL deficiency induced myeloid-derived suppressor cells as targets and biomarkers for lung cancer

BackgroundMyeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells in tumor microenvironment, which suppress antitumor immunity. Expansion of various MDSC subpopulations is closely associated with poor clinical outcomes in...

A SURVEY OF ACYLCARNITINE METHODS AND QUALITY CONTROL PROTOCOLS FROM CLINICAL LABORATORIES SUBMITTED ON BEHALF OF THE SIMD LABORATORY WORKGROUP

Lysosomal acid lipase deficiency (LAL-D) is a phenotypic continuum between the severe Wolman disease and the attenuated cholesteryl ester storage disease (CESD).To study if the amount of residual LAL enzymatic activity in dried blood spots (DBS) correlates with the LAL-D disease severity.DBS from Wolman and CESD patients, LAL-D carriers, and presumably unaffected random newborns were acquired. LAL enzymatic activity in DBS were measured using a novel, highly specific LAL substrate.Patients with Wolman disease displayed significantly lower LAL enzymatic activity compared to CESD patients. This was not observed with the traditional assay in which a non-specific substrate was used together with an LAL-specific inhibitor.The new LAL enzymatic activity assay using the specific substrate offers an improved biochemical genetics method for the diagnosis of LAL-D in symptomatic patients and more importantly, for the prognosis of asymptomatic patients who test positive in population-wide LAL-D newborn screening.

A Novel Variant in the LIPA Gene Associated with Distinct Phenotype.

Deficiency of lysosomal acid lipase (LAL-D) is caused by biallelic pathogenic variants in the LIPA gene. Spectrum of LAL-D ranges from early onset of hepatosplenomegaly and psychomotor regression (Wolman disease) to a more chronic course (cholesteryl ester storage disease - CESD). The diagnosis is based on lipid and biomarker profiles, specific liver histopathology, enzyme deficiency, and identification of causative genetic variants. Biomarker findings are a useful for diagnostics of LAL-D, including high plasma concentration of chitotriosidase as well as elevated oxysterols. Current treatment options include enzyme replacement therapy (sebelipase-alpha), statins, liver transplantation, and stem cell transplantation. We present two pairs of siblings from Serbia with a distinctive phenotype resembling LAL-D with a novel variant of unknown significance (VUS) detected in the LIPA gene and residual LAL activity. All patients presented with hepatosplenomegaly at early childhood. In siblings from family 1, compound heterozygosity for a pathogenic c.419G>A (p.Trp140Ter) variant and a novel VUS c.851C>T (p.Ser284Phe) was detected. Patients from family 2 were homozygous for c.851C>T VUS and both have typical histopathologic findings for LAL-D in the liver. Enzyme activity of LAL was tested in three patients and reported as sufficient, and therefore enzyme replacement therapy could not be approved. When confronted with a challenge of diagnosing an inherited metabolic disorder, several aspects are taken into consideration: clinical manifestations, specific biomarkers, enzyme assay results, and molecular genetic findings. This report brings cases to light which have a considerable discrepancy between those aspects, namely the preserved LAL enzyme activity in presence of clinical manifestations and rare variants in the LIPA gene.