Cathepsin D Research Articles

Osteoprotegerin predicts cardiovascular events in patients treated with haemodialysis.

Disturbances in bone mineral metabolism are associated with increased mortality and cardiovascular events (CVEs). However, the association between bone-associated protein biomarkers, mortality and CVEs independent of cytokine activation remains unknown. This study aimed to investigate bone-associated protein biomarkers and the association with inflammatory cytokines and cardiovascular (CV) outcomes. This prospective study enrolled haemodialysis patients in Denmark between December 2010 and March 2011. Using a proximity extension proteomics assay, nine bone-associated proteins were examined: cathepsin D (CTSD), cathepsin L1 (CTSL1), dickkopf-related protein 1, fibroblast growth factor 23, leptin, osteoprotegerin (OPG), receptor activator of nuclear factor kappa-Β ligand, TNF-related apoptosis-inducing ligand (TRAIL) and TRAIL receptor 2 (TRAIL-R2). The importance of the bone-associated protein markers was evaluated by a random forest (RF) algorithm. The association between bone-associated proteins with all-cause death, CV death and CVEs was analysed in multivariable Cox models adjusted for age, gender, comorbidities, laboratory data and dialysis duration. We enrolled 331 patients [63.7% men; mean age, 65 years (standard deviation 14.6)] in a prospective cohort study with 5 years of follow-up. When adjusting for confounders, CTSL1 remained associated with all-cause death and four biomarkers were associated with CVEs. However, the association between bone markers and the outcomes was attenuated after adjusting for inflammatory proteins and only OPG remained associated with CVEs in the adjusted model. Evaluating the importance of bone markers by RF, OPG was the most important marker related to CVEs. OPG also improved the prediction of CVEs in integrated discrimination improvement and net reclassification improvement analyses. OPG, a well-known bone biomarker, was associated with CVEs independent of cytokine activity. In contrast, the association between CVEs and the remaining three bone-associated proteins (TRAIL-R2, CTSD and CTSL1) was affected by cytokine inflammation activity.

Analysis of silymarin-modulating effects against acrylamide-induced cerebellar damage in male rats: Biochemical and pathological markers

BackgroundAcrylamide (ACR) is a well-proven neurotoxin and potential food carcinogen in humans and rodent models. Silymarin (SIL) is a flavonoid mixture isolated from seeds, leaves, and fruits of Silymarin marianum (milk thistle) that possesses a free-radical scavenging effect. ObjectiveIn this work, the primary focus was to investigate the efficacy of SIL to mitigate ACR-induced subacute neurotoxic effects and oxidative changes in rat cerebellum. MethodsAdult male rats were treated intraperitoneally with ACR (50 mg/kg) with or without SIL (160 mg/kg). The neuropathology and biochemical parameters viz. lipid peroxidation (measured as levels of malondialdehyde or MDA), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), serotonin (5-hydroxytryptamine; 5-HT), dopamine (DA), and cathepsin D (CTSD) in the cerebellum have been evaluated. ResultsThe data showed that ACR induced redox disruptions as measured by increased MDA levels and inhibition of CAT, SOD, and GPx antioxidant enzyme activities. Besides, cerebellar monoamine neurotransmitters, 5-HT and DA, were depleted in ACR-treated rats. Furthermore, ACR administration caused a significant elevation of CTSD activity, indicating that ACR could trigger apoptosis or apoptosis-like death. At the tissue level, cerebellar cortex sections from ACR-treated animals were characterized by severe neuronal damage. The administration of SIL to ACR-treated rats remarkably alleviated all the aforementioned ACR-induced effects. ConclusionSIL has a potent therapeutic effect against ACR-induced cerebellar neurotoxicity in experimental rats via the attenuation of oxidative/antioxidative responses and the inhibition of CTSD-activity.

Overexpression of Lipocalin-2 Inhibits Proliferation and Invasiveness of Human Glioblastoma Multiforme Cells by Activating ERK Targeting Cathepsin D Expression.

Simple SummaryLipocalin-2 (LCN2) exhibits pro- and anti-carcinogenic effects in several cancers, but its role in the progression of glioblastoma multiforme (GBM) remains poorly understood. We observed that the overexpression of LCN2 inhibits GBM cell proliferation and invasion via activation of ERK-induced CTSD expression. LCN2 overexpression may be a treatment strategy and prognostic marker for GBM.Lipocalin-2 (LCN2) exhibits pro- and anti-carcinogenic effects in several cancers, but its role in the progression of glioblastoma multiforme (GBM) remains unclear. This study aims to elucidate the effect of LCN2 in human GBM cell, and the mechanism underlying its effects on GBM malignant progression. We observed that LCN2 expression was significantly lower in GBM than in normal tissues and was associated with poorer GBM patient survival. LCN2-overexpressing GBM cells showed significantly reduced proliferation and migration/invasion abilities. Human protease antibody array analysis showed that the expression of cathepsin D (CTSD) protein and mRNA was lower in LCN2-overexpressing GBM cells than in controls. Higher CTSD expression was observed in GBM tumors than in normal tissues, and higher CTSD expression was associated with poorer overall and disease-free survival. LCN2-overexpressing GBM cells exhibited increased ERK phosphorylation. Treatment of these cells with a MEK inhibitor (U0126) restored CTSD expression, cell migration, and cell invasiveness. In conclusion, LCN2 might be serving as a prognostic marker and promising anti-proliferative and anti-metastatic target for treating GBM.

DDRGK1, a crucial player of ufmylation system, is indispensable for autophagic degradation by regulating lysosomal function

DDRGK domain-containing protein 1 (DDRGK1) is an important component of the newly discovered ufmylation system and its absence has been reported to induce extensive endoplasmic reticulum (ER) stress. Recently, emerging evidence indicates that the ufmylation system is correlated with autophagy, although the exact mechanism remains largely unknown. To explore the regulation mechanism of DDRGK1 on autophagy, in this study, we established an immortalized mouse embryonic fibroblast (MEF) cell lines harvested from the DDRGK1F/F:ROSA26-CreERT2 mice, in which DDRGK1 depletion can be induced by 4-hydroxytamoxifen (4-OHT) treatment. Here, we show that DDRGK1 deficiency in MEFs has a dual effect on autophagy, which leads to a significant accumulation of autophagosomes. On one hand, it promotes autophagy induction by impairing mTOR signaling; on the other hand, it blocks autophagy degradation by inhibiting autophagosome–lysosome fusion. This dual effect of DDRGK1 depletion on autophagy ultimately aggravates apoptosis in MEFs. Further studies reveal that DDRGK1 loss is correlated with suppressed lysosomal function, including impaired Cathepsin D (CTSD) expression, aberrant lysosomal pH, and v-ATPase accumulation, which might be a potential trigger for impairment in autophagy process. Hence, this study confirms a crucial role of DDRGK1 as an autophagy regulator by controlling lysosomal function. It may provide a theoretical basis for the treatment strategies of various physiological diseases caused by DDRGK1 deficiency.

Internalization of Clostridium botulinum C2 Toxin Is Regulated by Cathepsin B Released from Lysosomes.

Clostridium botulinum C2 toxin is a clostridial binary toxin consisting of actin ADP-ribosyltransferase (C2I) and C2II binding components. Activated C2II (C2IIa) binds to cellular receptors and forms oligomer in membrane rafts. C2IIa oligomer assembles with C2I and contributes to the transport of C2I into the cytoplasm of host cells. C2IIa induces Ca2+-induced lysosomal exocytosis, extracellular release of the acid sphingomyelinase (ASMase), and membrane invagination and endocytosis through generating ceramides in the membrane by ASMase. Here, we reveal that C2 toxin requires the lysosomal enzyme cathepsin B (CTSB) during endocytosis. Lysosomes are a rich source of proteases, containing cysteine protease CTSB and cathepsin L (CTSL), and aspartyl protease cathepsin D (CTSD). Cysteine protease inhibitor E64 blocked C2 toxin-induced cell rounding, but aspartyl protease inhibitor pepstatin-A did not. E64 inhibited the C2IIa-promoted extracellular ASMase activity, indicating that the protease contributes to the activation of ASMase. C2IIa induced the extracellular release of CTSB and CTSL, but not CTSD. CTSB knockdown by siRNA suppressed C2 toxin-caused cytotoxicity, but not siCTSL. These findings demonstrate that CTSB is important for effective cellular entry of C2 toxin into cells through increasing ASMase activity.

Molecular Characterization, Tissue Distribution, and Expression Profiling of the CTSD Gene during Goose Ovarian Follicle Development

Cathepsin D (CTSD) is known to be crucial for the degradation and utilization of yolk precursors in ovarian follicles. However, little is known about its expression profiles and physiological actions in avian ovarian cells. In this study, the intact coding sequence of the CTSD gene in geese was cloned for the first time, with a length of 1197 bp. It encoded a polypeptide of 398 amino acids (AA) consisting of a signal peptide and two conserved functional domains (i.e., A1_Propeptide and Cathepsin_D2). The AA sequence of goose CTSD had > 96% similarities with the homologs of turkeys, chickens, and ducks. Results from real-time PCR showed that goose CTSD mRNA was present in all tissues examined, with higher levels in the adrenal gland, liver, heart, and reproductive organs. Furthermore, levels of CTSD mRNA were much higher in goose granulosa layers than in the theca layers in any follicular category. Significantly, its expression remained almost unchanged in the theca layers throughout follicle development, while it increased gradually in the granulosa layers from 2-4 mm to F5 follicles but declined there after. These results suggested that CTSD may regulate goose ovarian follicle development through its actions on both the degradation and absorption of yolk precursors and granulosa cell apoptosis.

A novel deletion variant in CLN3 with highly variable expressivity is responsible for juvenile neuronal ceroid lipofuscinoses.

Mutations in CLN3 (OMIM: 607042) are associated with juvenile neuronal ceroid lipofuscinoses (JNCL)-a rare neurodegenerative disease with early retinal degeneration and progressive neurologic deterioration. The study aimed to determine the underlying genetic factors justifying the NCL phenotype in a large Iraqi consanguineous family. Four affected individuals with an initial diagnosis of NCL were recruited. By doing neuroimaging and also pertinent clinical examinations, e.g. fundus examination, due to heterogeneity of neurodevelopmental disorders, the proband was subjected to the paired-end whole-exome sequencing to identify underlying genetic factors. The candidate variant was also confirmed by Sanger sequencing. Various in silico predictions were used to show the pathogenicity of the variant. This study revealed a novel homozygous frameshift variant-NM_000086.2: c.1127del; p.(Leu376Argfs*15)-in the exon 14 of the CLN3 gene as the most likely disease-causing variant. Three out of 4 patients showed bilateral vision loss (< 7years) and retinal degeneration with macular changes in both eyes. Electroencephalography demonstrated the loss of normal posterior alpha rhythm and also low amplitude multifocal slow waves. Brain magnetic resonance imaging of the patients with a high degree of deterioration showed mild cerebral and cerebellar cortical atrophy, mild ventriculomegaly, thinning of the corpus callosum and vermis, and non-specific periventricular white matter signal changes in the occipital area. The novel biallelic deletion variant of CLN3 was identified that most probably led to JNCL with variable expressivity of the phenotype. This study also expanded our understanding of the clinical and genetic spectrum of JNCL.

Effect of small molecule eRF3 degraders on premature termination codon readthrough.

Premature termination codon (PTC) readthrough is considered a potential treatment for genetic diseases caused by nonsense mutations. High concentrations of aminoglycosides induce low levels of PTC readthrough but also elicit severe toxicity. Identifying compounds that enhance PTC readthrough by aminoglycosides or reduce their toxicity is a continuing challenge. In humans, a binary complex of eukaryotic release factors 1 (eRF1) and 3 (eRF3a or eRF3b) mediates translation termination. They also participate in the SURF (SMG1-UPF1-eRF1-eRF3) complex assembly involved in nonsense-mediated mRNA decay (NMD). We show that PTC readthrough by aminoglycoside G418 is considerably enhanced by eRF3a and eRF3b siRNAs and cereblon E3 ligase modulators CC-885 and CC-90009, which induce proteasomal degradation of eRF3a and eRF3b. eRF3 degradation also reduces eRF1 levels and upregulates UPF1 and selectively stabilizes TP53 transcripts bearing a nonsense mutation over WT, indicating NMD suppression. CC-90009 is considerably less toxic than CC-885 and it enhances PTC readthrough in combination with aminoglycosides in mucopolysaccharidosis type I-Hurler, late infantile neuronal ceroid lipofuscinosis, Duchenne muscular dystrophy and junctional epidermolysis bullosa patient-derived cells with nonsense mutations in the IDUA, TPP1, DMD and COL17A1 genes, respectively. Combination of CC-90009 with aminoglycosides such as gentamicin or ELX-02 may have potential for PTC readthrough therapy.

Cathepsin B and D deficiency in the mouse pancreas induces impaired autophagy and chronic pancreatitis

The major lysosomal proteases, Cathepsin B (CTSB), Cathepsin D (CTSD) and Cathepsin L (CTSL), are implicated in autophagic activity. To investigate the role of each cathepsin in the exocrine pancreas, we generated mice in which the pancreas was specifically deficient in Ctsb, Ctsd and Ctsl. Each of these gene knockout (KO) and Ctsb;Ctsl and Ctsd;Ctsl double-knockout (DKO) mice were almost normal. However, we found cytoplasmic degeneration in the pancreatic acinar cells of Ctsb;Ctsd DKO mice, similar to autophagy related 5 (Atg5) KO mice. LC3 and p62 (autophagy markers) showed remarkable accumulation and the numbers of autophagosomes and autolysosomes were increased in the pancreatic acinar cells of Ctsb;Ctsd DKO mice. Moreover, these Ctsb;Ctsd DKO mice also developed chronic pancreatitis (CP). Thus, we conclude that both Ctsb and Ctsd deficiency caused impaired autophagy in the pancreatic acinar cells, and induced CP in mice.

A case of juvenile CLN1– challenge in diagnosis and epilepsy treatment

ABSTRACT Introduction Classic onset of CLN1 disease is within the first year of life with developmental arrest, epilepsy and rapid progression. In an atypical variant of CLN1 disease onset is later in the juvenile epoch. Although epilepsy in the juvenile form of CLN1 often is less severe than in typical CLN1, treatment of seizures and status epilepticus may be challenging. Case presentation The clinical course, misdiagnosis and epilepsy phenotype are presented in a girl with juvenile CLN1. Cognitive and neurologic regression started at age 5.5 years. Epilepsy was a major clinical issue as the patient suffered from focal seizures, recurrent status epilepticus and epilepsia partialis continua. In one episode of refractory status epilepticus, the patient had significant bradycardia associated with the intravenous infusion of levetiracetam. Diagnosis was made at the age of 12 years, based on palmitoyl protein-thioesterase (PPT) enzyme deficiency and genetic testing that documented a homozygous exon missense mutation in the CLN1 gene (PPT1, c.541G>A, p.Val181Met). Discussion Epilepsy in all NCL patients is a major clinical issue and presumed related to neuronal excitation and epileptogenesis. The treatment of status epilepticus, in juvenile CLN1 patients, presents a particular challenge and requires monitoring of potential serious pharmacologic side effects of therapy.

Noise Reduction Effect of Deep-learning-based Image Reconstruction Algorithms in Thin-section Chest CT

To evaluate the noise reduction effect of deep learning-based reconstruction algorithms in thin-section chest CT images by analyzing images reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), and deep learning image reconstruction (DLIR) algorithms. The chest CT scan raw data of 47 patients were included in this study. Images of 0.625 mm were reconstructed using six reconstruction methods, including FBP, ASIR hybrid reconstruction (ASIR50%, ASIR70%), and deep learning low, medium and high modes (DL-L, DL-M, and DL-H). After the regions of interest were outlined in the aorta, skeletal muscle and lung tissue of each group of images, the CT values, SD values and signal-to-noise ratio (SNR) of the regions of interest were measured, and two radiologists evaluated the image quality. CT values, SD values and SNR of the images obtained by the six reconstruction methods showed statistically significant difference ( P<0.001). There were statistically significant differences in the image quality scores of the six reconstruction methods ( P<0.001). Images reconstruced with DL-H have the lowest noise and the highest overall quality score. The model based on deep learning can effectively reduce the noise of thin-section chest CT images and improve the image quality. Among the three deep-learning models, DL-H showed the best noise reduction effect.

Impact of cathepsin D activity and C224T polymorphism (rs17571) on chronic obstructive pulmonary disease: correlations with oxidative and inflammatory markers.

Cathepsin D (CTSD) is an aspartyl proteinase that plays an important role in protein degradation, antigen processing and apoptosis. It has been associated with several pathologies such as cancer, Alzheimer's disease and inflammatory disorders. Its function in lung diseases remains, however, controversial. In the current study, we determined CTSD activity in serum of patients with chronic obstructive pulmonary disease (COPD) and evaluated the correlations between this proteinase and inflammatory and oxidative parameters. We also investigated the impact of a CTSD C224T polymorphism on enzyme activity and clinicopathological parameters. Our population included 211 healthy controls and 138 patients with COPD. CTSD activity, MMPs (-1/-7/-12), cytokines (IL-6, TNF-α), malondialdehyde (MDA), nitric oxide and peroxynitrite levels were measured in patients and controls using standard methods. Genotyping of CTSD C224T polymorphism was determined using PCR-RFLP. Our results showed an increased CTSD activity in COPD patients compared to healthy controls (4.87 [3.99-6.07] vs. 3.94 [2.91-5.84], respectively, p < 0.001). COPD smokers presented also a higher CTSD activity when compared to nonsmokers (4.91[3.98-6.18] vs. 4.65[4.16-5.82], respectively, p = 0.01), while no differences were found when subjects were compared according to their GOLD stages. The activity of this proteinase was not dependent on the C224T polymorphism because we did not found any influence of this SNP on proteinase activity among patients and controls. Furthermore, our data provide the first evidence of the interrelationships between CTSD activity and both MMPs and TNF-α levels (MMP-1[r = -0.4; p = 0.02], MMP-7[r = 0.37; p = 0.04], MMP-12[r = 0.43; p = 0.02], TNF-α [r = 0.89, p = 0.001]) in COPD smokers. There were no correlations, however, between CTSD activity and oxidative stress parameters in controls and patients. Our findings suggest that CTSD could be a relevant marker for COPD disease. Alteration of CTSD activity may be related to increased MMPs and TNF-α levels, particularly in COPD smokers.

Cathepsin D Variants Associated With Neurodegenerative Diseases Show Dysregulated Functionality and Modified α-Synuclein Degradation Properties.

Cathepsin D (CTSD) is a lysosomal protease important for the degradation of various substrates, including disease-associated proteins like α-synuclein (a-syn), amyloid precursor protein (APP) and tau, all of which tend to aggregate if not efficiently degraded. Hence, it is not surprising that genetic variants within the CTSD gene have been linked to neurodegenerative diseases, like Parkinson’s and Alzheimer’s disease (PD, AD), as well as the lysosomal storage disorder neuronal ceroid lipofuscinosis type-10 (NCL10). Although recent studies have shown the molecular dependence of substrate degradation via CTSD within autophagic pathways, only little is known about the precise role of lysosomal CTSD function in disease development. We here performed biochemical, cellular and structural analyses of eleven disease-causing CTSD point mutations found in genomic sequencing data of patients to understand their role in neurodegeneration. These CTSD variants were analyzed for cellular localization, maturation and enzymatic activity in overexpression analyses. Moreover, for PD-associated mutants, intracellular degradation of a-syn was monitored. In summary, our results suggest that NCL10-associated CTSD variants are significantly impaired in lysosomal maturation and enzymatic activity, whereas the AD- and PD-associated variants seemed rather unaffected, indicating normal maturation, and lysosomal presence. Interestingly, a PD-associated CTSD variant (A239V) exhibited increased enzymatic activity accompanied by enhanced a-syn degradation. By structural analyses of this mutant utilizing molecular dynamics simulation (MDS), we identified a structural change within a loop adjacent to the catalytic center leading to a higher flexibility and potentially accelerated substrate exchange rates. Our data sheds light onto the role of CTSD in disease development and helps to understand the structural regulation of enzymatic function, which could be utilized for targeted CTSD activation. Because of the degradative function of CTSD, this enzyme is especially interesting for therapeutic strategies tackling protein aggregates in neurodegenerative disorders.

A human model of Batten disease shows role of CLN3 in phagocytosis at the photoreceptor\u2013RPE interface

Mutations in CLN3 lead to photoreceptor cell loss in CLN3 disease, a lysosomal storage disorder characterized by childhood-onset vision loss, neurological impairment, and premature death. However, how CLN3 mutations cause photoreceptor cell death is not known. Here, we show that CLN3 is required for phagocytosis of photoreceptor outer segment (POS) by retinal pigment epithelium (RPE) cells, a cellular process essential for photoreceptor survival. Specifically, a proportion of CLN3 in human, mouse, and iPSC-RPE cells localized to RPE microvilli, the site of POS phagocytosis. Furthermore, patient-derived CLN3 disease iPSC-RPE cells showed decreased RPE microvilli density and reduced POS binding and ingestion. Notably, POS phagocytosis defect in CLN3 disease iPSC-RPE cells could be rescued by wild-type CLN3 gene supplementation. Altogether, these results illustrate a novel role of CLN3 in regulating POS phagocytosis and suggest a contribution of primary RPE dysfunction for photoreceptor cell loss in CLN3 disease that can be targeted by gene therapy.

Neuronal ceroid lipofuscinosis: genetic and phenotypic spectrum of 14 patients from Turkey.

Neuronal ceroid lipofuscinoses (NCLs) is a group of congenital metabolic diseases where the neurodegenerative process with the accumulation of ceroid and lipofuscin autofluorescent storage materials is at the forefront. According to the age of presentation, NCLs are classified as congenital, infantile (INCL), late infantile (LINCL), juvenile (JNCL), and adult (ANCL) NCLs. In our study, it was aimed to discuss the clinical and molecular characteristics of our patients diagnosed with NCL. This is a descriptive cross-sectional study which was conducted in 14 patients from 10 unrelated families who were diagnosed with different types of NCL based on clinical presentation, neuroimaging, biochemical measurements, and molecular analyses, at the department of pediatric metabolism between June 2015 and June 2020. A total of 14 patients were diagnosed with different types of NCL. Of those, 4 patients were diagnosed with NCL7 (4/14; 30%), 3/14 (23%) with NCL1, 3/14 (23%) with NCL2, 2/14 (14.2%) with NCL13, and 1/14 (7.1%) with NCL10. Eleven pathogenic variants were detected, 5 of which are novel (c.721G>T [p.Gly241Ter] and c.301G>C [p.Ala146Pro] in MFDS8 gene; c.316C>T [p.Gln106Ter] in PPT1 gene; c.341C>T [p.Ala114Val] in TPP1 gene; c.686A>T [p.Glu229Val] in CTSD gene) CONCLUSION: This study is one of the pioneer comprehensive researches from Turkey that provides information about disease-causing variants and clinical presentation of different and rare types of NCLs. The identification of novel variants and phenotypic expansion is important for genetic counselling in Turkey and expected to improve understanding of NCLs.

Protein regulation strategies of the mouse spleen in response to Babesia microti infection

BackgroundBabesia is a protozoan parasite that infects red blood cells in some vertebrates. Some species of Babesia can induce zoonoses and cause considerable harm. As the largest immune organ in mammals, the spleen plays an important role in defending against Babesia infection. When infected with Babesia, the spleen is seriously injured but still actively initiates immunomodulatory responses.MethodsTo explore the molecular mechanisms underlying the immune regulation and self-repair of the spleen in response to infection, this study used data-independent acquisition (DIA) quantitative proteomics to analyse changes in expression levels of global proteins and in phosphorylation modification in spleen tissue after Babesia microti infection in mice.ResultsAfter mice were infected with B. microti, their spleens were seriously damaged. Using bioinformatics methods to analyse dynamic changes in a large number of proteins, we found that the spleen still initiated immune responses to combat the infection, with immune-related proteins playing an important role, including cathepsin D (CTSD), interferon-induced protein 44 (IFI44), interleukin-2 enhancer-binding factor 2 (ILF2), interleukin enhancer-binding factor 3 (ILF3) and signal transducer and activator of transcription 5A (STAT5A). In addition, some proteins related to iron metabolism were also involved in the repair of the spleen after B. microti infection, including serotransferrin, lactoferrin, transferrin receptor protein 1 (TfR1) and glutamate-cysteine ligase (GCL). At the same time, the expression and phosphorylation of proteins related to the growth and development of the spleen also changed, including protein kinase C-δ (PKC-δ), mitogen-activated protein kinase (MAPK) 3/1, growth factor receptor-bound protein 2 (Grb2) and P21-activated kinase 2 (PAK2).ConclusionsImmune-related proteins, iron metabolism-related proteins and growth and development-related proteins play an important role in the regulation of spleen injury and maintenance of homeostasis. This study provides an important basis for the diagnosis and treatment of babesiosis.Graphical

Biomarkers and Their Relation to Cardiac Function Late After Peripartum Cardiomyopathy

BackgroundAngiogenic imbalance involving the placental protein soluble Fms-like tyrosine kinase-1 (sFlt-1) and cleavage of the nursing-hormone prolactin by the enzyme cathepsin D (CD) both play a role in the pathogenesis of peripartum cardiomyopathy (PPCM). We hypothesized that angiogenic imbalance and increased activity of CD have a long-lasting impact in women with PPCM. Methods and ResultsA nationwide Danish cohort of women with PPCM (PPCM group, n = 28), age matched women with previous preeclampsia (n = 28) and uncomplicated pregnancies (n = 28) participated in a follow-up study including biomarker analysis, exercise testing and cardiac magnetic resonance imaging. The median time to follow-up was 91 months (range 27–137 months) for the PPCM group. Levels of sFlt-1, placental growth factor, N-terminal pro-natriuretic brain peptide, and copeptin were all significantly higher in the PPCM group. More women in the PPCM group had detectable CD activity (68%) compared with the preeclampsia group (29%) and uncomplicated pregnancies group (36%) (P = .0002). Levels of angiogenic factors and biomarkers correlated inversely with maximal exercise capacity and cardiac functional parameters assessed with cardiac magnetic resonance imaging. ConclusionsWomen with PPCM had higher biomarker levels and CD activity up to 7 years after diagnosis. Higher biomarker levels correlated inversely with maximal exercise capacity and markers of cardiac dysfunction suggesting that persistent angiogenic imbalance and increased CD activity is associated with residual cardiac dysfunction.

Insulin resistance is positively associated with plasma cathepsin D activity in NAFLD patients.

Previous studies associated plasma cathepsin D (CTSD) activity with hepatic insulin resistance in overweight and obese humans. Insulin resistance is a major feature of non-alcoholic fatty liver disease (NAFLD) and is one of the multiple hits determining the progression towards non-alcoholic steatohepatitis (NASH). In line, we have previously demonstrated that plasma CTSD levels are increased in NASH patients. However, it is not known whether insulin resistance associates with plasma CTSD activity in NAFLD. To increase our understanding regarding the mechanisms by which insulin resistance mediates NAFLD, fifty-five liver biopsy or MRI-proven NAFLD patients (BMI>25kg/m2) were included to investigate the link between plasma CTSD activity to insulin resistance in NAFLD. We concluded that HOMA-IR and plasma insulin levels are independently associated with plasma CTSD activity in NAFLD patients (standardized coefficient β: 0.412, 95% Cl: 0.142~0.679, p=0.004 and standardized coefficient β: 0.495, 95% Cl: 0.236~0.758, p=0.000, respectively). Together with previous studies, these data suggest that insulin resistance may link to NAFLD via elevation of CTSD activity in plasma. As such, these data pave the way for testing CTSD inhibitors as a pharmacological treatment of NAFLD.

Myosteatosis in NAFLD patients correlates with plasma Cathepsin D.

Previously, we have shown that hepatic lipid accumulation induces the secretion of cathepsin D (CTSD), and that plasma CTSD levels are associated with increased inflammation and disease severity in nonalcoholic fatty liver disease (NAFLD). Although it is clear that the liver is a major source of plasma CTSD, it is unknown whether other metabolically active organs such as the muscle, also associate with plasma CTSD levels in NAFLD patients. Therefore, the aim of this study was to explore the relation between lipid accumulation in the muscle (myosteatosis) and plasma CTSD levels in forty-five NAFLD patients. We observed that hepatic steatosis positively associated with plasma CTSD levels, confirming the previously established link between plasma CTSD and the liver. Furthermore, a positive association between myosteatosis and plasma CTSD levels was observed, which was independent of sex, age, BMI, waist circumference and hepatic steatosis. By establishing a positive association between myosteatosis and plasma CTSD levels, our findings suggest that, in addition to the liver, the muscle is also linked to plasma CTSD levels in NAFLD patients. The observed link between myosteatosis and plasma CTSD levels supports the concept of a significant role of the skeletal muscle in metabolic disturbances in metabolic syndrome-related disorders.

Bisphenol F induces nonalcoholic fatty liver disease-like changes: Involvement of lysosome disorder in lipid droplet deposition.

Epidemiological studies have demonstrated that the general population's exposure to bisphenol A (BPA) substitutes is ubiquitous. Bisphenol F (BPF), one of the main BPA substitutes, is increasingly replacing BPA in plastics for food and beverage applications. Accumulating evidence suggests that BPA exposure is associated with nonalcoholic fatty liver disease (NAFLD)-like changes. However, the potential effects of BPF on lipid homeostasis remain poorly understood. In the present study, an epidemiological analysis with LC-MS-MS revealed that the BPF concentrations in the serum of NAFLD patients were significantly higher than those in a control group. Supporting this result, using Oil Red O, BODIPY 493/503, LipidTox Deep Red staining and gas chromatography-time-of-flight mass spectrometry (TOF-MS) assays, we found that BPF exposure induced NAFLD-like changes, with obvious lipid droplet deposition, triglyceride (TG) and fatty acids increase in mouse livers. Meanwhile, lipid droplet deposition and TG increase induced by BPF were also observed in HepG2 cells, accompanied by autophagic flux blockade, including autophagosome accumulation and the decreased degradation of SQSTM1/p62. Using adenoviruses dual-reporter plasmid RFP-GFP-LC3, RFP-GFP-PLIN2 transfection, AO staining, and EGFR degradation assays, we demonstrated that BPF treatment impaired lysosomal degradative capacity, since BPF treatment obviously impaired lysosomal acidification, manifested as decreased lysosomal hydrolase cathepsin L (CTSL) and mature cathepsin D (CTSD) in HepG2 and mouse liver issues. Additionally, v-ATPase D, a multi-subunit enzyme that mediates acidification of eukaryotic intracellular organelles, significantly decreased after BPF exposure in both the vitro and invivo studies. This study ascertained a novel mechanism involving dysfunctional of lysosomal degradative capacity induced by BPF, which contributes to lipophagic disorders and causes lipid droplet deposition. This work provides evidence that lysosomes may be a target organelle where BPF exerts its potential toxicity; therefore, novel intervention strategies targeting lysosome are promising for BPF-induced NAFLD-like changes.