LAMP2 Expression Research Articles

Visualisation and characterisation of mononuclear phagocytes in the chicken respiratory tract using CSF1R-transgenic chickens

The respiratory tract is a key organ for many avian pathogens as well as a major route for vaccination in the poultry industry. To improve immune responses after vaccination of chickens through increased uptake of vaccines and targeting to antigen presenting cells, a better understanding of the avian respiratory immune system is required. Transgenic MacReporter birds were used expressing a reporter gene (eGFP or mApple) under the control of the CSF1R promoter and enhancer in cells of the mononuclear phagocyte (MNP) lineage to visualize the ontogeny of the lymphoid tissue, macrophages and dendritic cells, in the trachea, lung and air sac of birds from embryonic day 18–63 weeks of age. Small aggregates of CSF1R-transgene+ cells start to form at the openings of the secondary bronchi at 1 week of age, indicative of the early development of the organised bronchus-associated lymphoid tissue. Immunohistochemical staining revealed subpopulations of MNPs in the lung, based on expression of CSF1R-transgene, CD11, TIM4, LAMP1, and MHC II. Specialised epithelial cells or M cells covering the bronchus-associated lymphoid tissue expressed CSF1R-transgene and type II pneumocytes expressed LAMP1 suggesting that these epithelial cells are phagocytic and transcytose antigen. Highly organised lymphoid tissue was seen in trachea from 4 weeks onwards. Throughout the air sacs at all ages, CSF1R-transgene+ cells were scattered and at later stages, CSF1R-transgene+ cells lined capillaries. These results will serve as a base for further functional characterization of macrophages and dendritic cells and their role in respiratory diseases and vaccine responses.

17β-Estradiol Enhances Schwann Cell Differentiation via the ERβ-ERK1/2 Signaling Pathway and Promotes Remyelination in Injured Sciatic Nerves.

Remyelination is critical for nerve regeneration. However, the molecular mechanism involved in remyelination is poorly understood. To explore the roles of 17β-estradiol (E2) for myelination in the peripheral nervous system, we used a co-culture model of rat dorsal root ganglion (DRG) explants and Schwann cells (SCs) and a regeneration model of the crushed sciatic nerves in ovariectomized (OVX) and non-ovariectomized (non-OVX) rats for in vitro and in vivo analysis. E2 promoted myelination by facilitating the differentiation of SCs in vitro, which could be inhibited by the estrogen receptors (ER) antagonist ICI182780, ERβ antagonist PHTPP, or ERK1/2 antagonist PD98059. This suggests that E2 accelerates SC differentiation via the ERβ-ERK1/2 signaling. Furthermore, E2 promotes remyelination in crushed sciatic nerves of both OVX and non-OVX rats. Interestingly, E2 also significantly increased the expression of the lysosome membrane proteins LAMP1 and myelin protein P0 in the regenerating nerves. Moreover, P0 has higher degree of colocalization with LAMP1 in the regenerating nerves. Taking together, our results suggest that E2 enhances Schwann cell differentiation and further myelination via the ERβ-ERK1/2 signaling and that E2 increases the expression of myelin proteins and lysosomes in SCs to promotes remyelination in regenerating sciatic nerves.

Overexpression of Optic Atrophy Type 1 Protects Retinal Ganglion Cells and Upregulates Parkin Expression in Experimental Glaucoma.

Glaucoma is a neurodegenerative disease that features progressive loss of retinal ganglion cells (RGCs). Increasing evidences have revealed that impaired mitochondrial dynamics occurs early in neurodegenerative diseases. Optic Atrophy Type 1 (OPA1), a mitochondrial fusion protein, has recently been suggested to be a mitophagic factor. Our previous studies found that glaucomatous retinal damage may be ameliorated by an increase in mitochondrial OPA1. In this study, we explored the mechanism involved in OPA1 mediated neuroprotection and its relationship with parkin dependent mitophagy in experimental glaucoma models. Our data showed that overexpression of OPA1 by viral vectors protected against RGC loss, attenuated Bax expression, and improved mitochondrial health and mitochondrial surface area. Parkin expression and the number of mitophagosomes were upregulated in OPA1 overexpressed RGCs under glutamate excitotoxicity. While knockdown of OPA1 by siRNA decreased protein expression of parkin in RGCs under glutamate excitotoxicity. Two weeks after intraocular pressure (IOP) elevation, the LC3-II/I ratio and the LAMP1 expression were increased in OPA1 overexpressed optic nerve. These findings suggest that OPA1 overexpression may protect RGCs by ways of enhancing mitochondria fusion and parkin mediated mitophagy. Interventions to promote mitochondrial fusion and mitophagy may provide a useful strategy to battle against glaucomatous RGC loss.

Marsdenia tenacissima extract induces apoptosis and suppresses autophagy through ERK activation in lung cancer cells

BackgroundMarsdenia tenacissima is an herb medicine which has been utilized to treat malignant diseases for decades. The M. tenacissima extract (MTE) shows significant anti-proliferation activity against non-small cell lung cancer (NSCLC) cells, but the underlying mechanisms remain unclear. In this study, we explored the potential anti-proliferation mechanisms of MTE in NSCLC cells in relation to apoptosis as well as autophagy, which are two critical forms to control cancer cell survival and death.MethodsThe proliferation of H1975 and A549 cells was evaluated by MTT assay. Cell apoptosis was assessed by Annexin V and PI staining, Caspase 3 expression and activity. Autophagy flux proteins were detected by Western blot with or without autophagy inducer and inhibitor. Endogenous LC3-II puncta and LysoTracker staining were monitored by confocal microscopy. The formation of autophagic vacuoles was measured by acridine orange staining. ERK is a crucial molecule to interplay with cell autophagy and apoptosis. The role of ERK on cell apoptosis and autophagy influenced by MTE was determined in the presence of MEK/ERK inhibitor U0126.ResultsThe significant growth inhibition and apoptosis induction were observed in MTE treated NSCLC cells. MTE induced cell apoptosis coexisted with elevated Caspase 3 activity. MTE also impaired autophagic flux by upregulated LC3-II and p62 expression. Autophagy inducer EBSS could not abolish the impaired autophagic flux by MTE, while it was augmented in the presence of autophagy inhibitor Baf A1. The autophagosome–lysosome fusion was blocked by MTE via affecting lysosome function as evidenced by decreased expression of LAMP1 and Cathepsin B. The molecule ERK became hyperactivated after MTE treatment, but the MEK/ERK inhibitor U0126 abrogated autophagy inhibition and apoptosis induction caused by MTE, suggested that ERK signaling pathways partially contributed to cell death caused by MTE.ConclusionOur results demonstrate that MTE caused apoptosis induction as well as autophagy inhibition in NSCLC cells. The activated ERK is partially associated with NSCLC apoptotic and autophagic cell death in response to MTE treatment. The present findings reveal new mechanisms for the anti-tumor activity of MTE against NSCLC.

LAMP1 Overexpression Predicts for Poor Prognosis in Diffuse Large B-cell Lymphoma

IntroductionLysosomal-associated membrane protein 1 (LAMP1) is a lysosomal and plasma membrane protein that contributes to tumor metastatic potential and differentiation. Patients and MethodsWe performed immunohistochemical staining to investigate LAMP1 protein expression levels in 122 diffuse large B-cell lymphoma (DLBCL) tumor samples and 45 reactive hyperplasia tissues. Correlations between LAMP1 expression, various clinicopathologic features, and patient prognosis were evaluated by univariate and multivariate analyses. ResultsLAMP1 expression was greater in the DLBCL tissues than in the reactive hyperplasia tissues. High LAMP1 expression was significantly associated with a high international prognostic index (score, 3-5; P = .023) and elevated lactate dehydrogenase level (P = .028). Moreover, high LAMP1 expression (P = .026), elevated serum lactate dehydrogenase level (P = .011), and high international prognostic index (P < .001) were independently associated with worse overall survival and progression-free survival. ConclusionThese data provide the first evidence that LAMP1 expression is associated with a poor prognosis in patients with DLBCL.

Inhibitors of lysosomal function or serum starvation in control or LAMP2 deficient cells do not modify the cellular levels of Parkinson disease-associated DJ-1/PARK 7 protein.

Mutations in PARK7/DJ-1 gene are associated with familial autosomal recessive Parkinson disease. Recently, lysosomes and chaperone mediated autophagy (CMA) has been reported to participate in the degradation of DJ-1/PARK7 protein. Lamp-2A isoform is considered as the lysosomal receptor for the uptake of proteins being degraded by the CMA pathway. We have used several cell lines with disrupted LAMP2 gene expression and their respective control cells to test the possible role of lysosomal degradation and in particular CMA in DJ-1 /PARK7 degradation. Interruption of LAMP-2 expression did not result in an increase of the steady-state protein levels of DJ-1 /PARK7, as it would have been expected. Furthermore, no change in DJ-1 /PARK7 protein levels were observed upon inhibition of lysosomal function with NH4Cl or NH4Cl plus leupeptin, or after activation of CMA by serum starvation for 24h. Accordingly, we have not found any evidence that DJ-1 /PARK7 protein levels are regulated via lysosomal degradation or the CMA pathway.

Lamp2 inhibits epithelial-mesenchymal transition by suppressing Snail expression in HCC.

Lysosomal associated membrane protein 2 (Lamp2) influences a broad range of physiological and pathological processes. However, little is known about the role of Lamp2 in hepatocellular carcinoma (HCC) metastasis. This study found that Lamp2 expression was significantly lower in HCC tissues than in adjacent nontumor tissues (ANTs), and its expression level correlated with HCC metastasis. Low Lamp2 expression was significantly correlated with the AFP serum level (> 20 ng/Ml, P = 0.024), capsular formation (absent, P = 0.024), and microvascular invasion (present, P < 0.001), and low expression of Lamp2 indicated a poor prognosis in HCC. LowLamp2 expression was an independent and significant risk factor for recurrence-free survival (RFS; P < 0.001) and overall survival (OS; P < 0.001) in HCC. In this study, we demonstrated that Lamp2 overexpression inhibited cell motility and invasiveness in vitro and inhibited lung metastasis in vivo. In addition, Lamp2 could reverse the EMT program. Lamp2 silencing by siRNA in HCC cell lines enhanced the expression of mesenchymal markers and decreased the expression of epithelial markers. Consistent with these findings, Lamp2 overexpression had the opposite effects. Mechanistically, we found that Lamp2 could suppress Snail expression, upregulate E-cadherin, and inhibit HCC cell epithelial-mesenchymal transition (EMT).Together, these findings suggest that Lamp2 attenuates EMT by suppressing Snail expression in HCC.

The C9orf72-interacting protein Smcr8 is a negative regulator of autoimmunity and lysosomal exocytosis.

While a mutation in C9ORF72 is the most common genetic contributor to amyotrophic lateral sclerosis (ALS), much remains to be learned concerning the function of the protein normally encoded at this locus. To elaborate further on functions for C9ORF72, we used quantitative mass spectrometry-based proteomics to identify interacting proteins in motor neurons and found that its long isoform complexes with and stabilizes SMCR8, which further enables interaction with WDR41. To study the organismal and cellular functions for this tripartite complex, we generated Smcr8 loss-of-function mutant mice and found that they developed phenotypes also observed in C9orf72 loss-of-function animals, including autoimmunity. Along with a loss of tolerance for many nervous system autoantigens, we found increased lysosomal exocytosis in Smcr8 mutant macrophages. In addition to elevated surface Lamp1 (lysosome-associated membrane protein 1) expression, we also observed enhanced secretion of lysosomal components-phenotypes that we subsequently observed in C9orf72 loss-of-function macrophages. Overall, our findings demonstrate that C9ORF72 and SMCR8 have interdependent functions in suppressing autoimmunity as well as negatively regulating lysosomal exocytosis-processes of potential importance to ALS.

Xiao-Xu-Ming Decoction Reduced Mitophagy Activation and Improved Mitochondrial Function in Cerebral Ischemia and Reperfusion Injury.

We investigated whether Xiao-Xu-Ming decoction reduced mitophagy activation and kept mitochondrial function in cerebral ischemia-reperfusion injury. Rats were randomly divided into 5 groups: sham, ischemia and reperfusion (IR), IR plus XXMD (60 g/kg/day) (XXMD60), IR plus cyclosporin A (10 mg/kg/day) (CsA), and IR plus vehicle (Vehicle). Focal cerebral ischemia and reperfusion models were induced by middle cerebral artery occlusion (MCAO). Cerebral infarct areas were measured by triphenyl tetrazolium chloride staining. Cerebral ischemic injury was evaluated by hematoxylin and eosin staining (HE) and Nissl staining. Ultrastructural features of mitochondria and mitophagy in the penumbra of the ischemic cortex were observed by transmission electron microscopy. Mitophagy was detected by immunofluorescence labeled with LC3B and VDAC1. Autophagy lysosome formation was observed by immunofluorescence labeled with LC3B and Lamp1. The expression of LC3B, Beclin1, and Lamp1 was analyzed by Western blot. The rats subjected to MCAO showed worsened neurological score and cell ischemic damage. These were all significantly reversed by XXMD or CsA. Moreover, XXMD/CsA notably downregulated mitophagy and reduced the increase in LC3, Beclin1, and Lamp1 expression induced by cerebral ischemia and reperfusion. The findings demonstrated that XXMD exerted neuroprotective effect via downregulating LC3, Beclin1, Lamp1, and mitochondrial p62 expression level, thus leading to the inhibition of mitophagy.

LAMP-1 gene is overexpressed in high grade glioma.

High-grade gliomas (HGG) are the most frequent brain tumors in adults. Glioblastoma multiforme (GBM) is their most aggressive form resistant to therapy. It was shown that inhibition ofautophagyreduced GBM development and autophagyinterfering agents are regarded as a new strategy to fight glioma cells. The lysosome-associated membrane proteins (LAMPs) display differential expression particularly in cancer. There are few data on their expression and especially on their molecular profile. The aim of the present study is to investigate the expression of LAMP-1 and LAMP-2 genes and proteins in HGG. Newly diagnosed patients with HGG and healthy controls were examined by immunohistochemistry and qPCR for both protein and mRNA levels of LAMP-1 and LAMP-2. The transcriptional activity of LAMP-1 in HGG was significantly higher compared to normal brain and to LAMP-2. The two glycoproteins were detected in the cytosol of tumor cells with varying intensity, LAMP-1 showing again enhanced expression. In conclusion, novel data on LAMP-1 overexpression in HGG are presented suggesting involvement of this gene and protein in cell adhesion and tumor progression. These findings might help the elucidation of the complex biological role of the multifunctional LAMPs proteins and to predict novel therapeutic targets in lysosomes.

Expression of Beclin-1 and LAMP-2 in Rat Hippocampus under Conditions of Simulated Gravity Overload in the Caudocranial Vector.

Structural changes in the rat hippocampus in response to chronic cerebrovascular disorders induced by gravity exposure in the caudocranial vector were studied. Qualitative and quantitative morphological analysis detected significant cytoarchitectonic changes in the pyramidal layer: spongiosis, manifest pericellular and perivascular edema, and a drastic increase in the counts of pyramidal neurons with signs of impairment in all hippocampal zones. The density of perikarya in the pyramidal layer decreased. Immunohistochemical study detected high expression of Beclin-1 in CA1 field. High expression of LAMP-2 was detected in CA4 field. Field CA2 was characterized by the maximum counts of damaged cells and high expression of Beclin-1 and LAMP-2.

Glycogen synthase kinase-3 (GSK-3) inactivation compensates for the lack of CD28 in the priming of CD8+ cytotoxic T-cells: Implications for anti-PD-1 immunotherapy

Abstract The rescue of exhausted CD8+ cytolytic T-cells (CTLs) by anti-programmed cell death-1 (anti-PD-1) immune checkpoint blockade has been found to require CD28 expression. At the same time, we have shown that the inactivation of the serine/threonine kinase glycogen synthase kinase (GSK)-3α/β with small-interfering RNAs (siRNAs) and small molecule inhibitors (SMIs) specifically down-regulates PD-1 expression for enhanced CD8+ CTL function and clearance of tumors and viral infections (Taylor et al., 2016 Immunity, 44(2):274-86, Taylor et al., 2017 Cancer Research, canres.0491.2017). It has been unclear whether the GSK-3α/β pathway accounts for CD28 costimulation of CD8+ CTL function. In this presentation, we show for the first time that the inactivation of GSK-3α/β through siRNA or by SMIs during priming can substitute CD28 co-stimulation in the potentiation of cytotoxic CD8+ CTL function against the EL-4 lymphoma cells expressing OVA peptide. The effect was seen using several structurally distinct GSK-3 SMIs and was accompanied by an increase in Lamp-1 and GZMB expression. Conversely, CD28 crosslinking obviated the need for GSK-3α/β inhibition in its enhancement of CTL function. Our findings support a model where GSK-3 is the central co-signal for CD28 priming of CD8+ CTLs in anti-PD-1 immunotherapy. Anti-PD-1 and GSK-3 SMIs cooperate synergistically to limit the growth of solid melanoma tumors in mice. We will present data on the altered nature of tumor-infiltrating lymphocytes (TILs) in response to anti-PD-1 versus GSK-3 blockade and combination therapy. Our findings outline a next-generation approach using small molecule inhibitors in combination with check-point blockade therapy for the elimination of tumors.

Evidence for the link between defective autophagy and inflammation in peripheral blood mononuclear cells of type 2 diabetic patients.

Autophagy was shown to modulate inflammation in immune cells. This study was designed to evaluate the association between autophagy and inflammation in peripheral blood mononuclear cells (PBMCs) of type 2 diabetic (T2D) and non-diabetic (ND) subjects. The autophagy markers were measured by real-time PCR and western blot. The gene expression of pro- and anti-inflammatory cytokines was assessed by real-time PCR. Reduced transcription of BECN1 and LAMP2 and unchanged expression of MAP1LC3B and ATG5 were observed in PBMCs of T2D patients. Decreased LC3B-II and increased p62/SQSTM1 levels were found in PBMCs of diabetic patients. The p-mTOR level was higher in PBMCs of diabetic patients. An increase in both IL-1β and TNF-α gene expression, along with a decrease in the expression of IL-10, was observed in PBMCs of T2D patients. TNF-α mRNA expression was inversely correlated with the mRNA expression of BECN1 and LAMP2. TNF-α and IL-1β expression were negatively correlated with the protein levels of LC3B-II. TNF-α and IL-1β expression had also a positive correlation with protein level of p62. IL-10 mRNA expression was positively correlated with the mRNA expression of BECN1 and LAMP2 and protein levels of LC3B-II and negatively correlated with protein level of p62. In addition, p-mTOR level was positively correlated with IL-1β and TNF-α mRNA expression. The results revealed a reduced autophagy in PBMCs of T2D patients that is liked with an enhanced inflammation. The suppression of autophagy in PBMCs of diabetic patients may be associated with the activation of the mTOR signaling.

De novo mutations of the ATP6V1A gene cause developmental encephalopathy with epilepsy.

V-type proton (H+) ATPase (v-ATPase) is a multi-subunit proton pump that regulates pH homeostasis in all eukaryotic cells; in neurons, v-ATPase plays additional and unique roles in synapse function. Through whole exome sequencing, we identified de novo heterozygous mutations (p.Pro27Arg, p.Asp100Tyr, p.Asp349Asn, p.Asp371Gly) in ATP6V1A, encoding the A subunit of v-ATPase, in four patients with developmental encephalopathy with epilepsy. Early manifestations, observed in all patients, were developmental delay and febrile seizures, evolving to encephalopathy with profound delay, hypotonic/dyskinetic quadriparesis and intractable multiple seizure types in two patients (p.Pro27Arg, p.Asp100Tyr), and to moderate delay with milder epilepsy in the other two (p.Asp349Asn, p.Asp371Gly). Modelling performed on the available prokaryotic and eukaryotic structures of v-ATPase predicted p.Pro27Arg to perturb subunit interaction, p.Asp100Tyr to cause steric hindrance and destabilize protein folding, p.Asp349Asn to affect the catalytic function and p.Asp371Gly to impair the rotation process, necessary for proton transport. We addressed the impact of p.Asp349Asn and p.Asp100Tyr mutations on ATP6V1A expression and function by analysing ATP6V1A-overexpressing HEK293T cells and patients' lymphoblasts. The p.Asp100Tyr mutant was characterized by reduced expression due to increased degradation. Conversely, no decrease in expression and clearance was observed for p.Asp349Asn. In HEK293T cells overexpressing either pathogenic or control variants, p.Asp349Asn significantly increased LysoTracker® fluorescence with no effects on EEA1 and LAMP1 expression. Conversely, p.Asp100Tyr decreased both LysoTracker® fluorescence and LAMP1 levels, leaving EEA1 expression unaffected. Both mutations decreased v-ATPase recruitment to autophagosomes, with no major impact on autophagy. Experiments performed on patients' lymphoblasts using the LysoSensor™ probe revealed lower pH of endocytic organelles for p.Asp349Asn and a reduced expression of LAMP1 with no effect on the pH for p.Asp100Tyr. These data demonstrate gain of function for p.Asp349Asn characterized by an increased proton pumping in intracellular organelles, and loss of function for p.Asp100Tyr with decreased expression of ATP6V1A and reduced levels of lysosomal markers. We expressed p.Asp349Asn and p.Asp100Tyr in rat hippocampal neurons and confirmed significant and opposite effects in lysosomal labelling. However, both mutations caused a similar defect in neurite elongation accompanied by loss of excitatory inputs, revealing that altered lysosomal homeostasis markedly affects neurite development and synaptic connectivity. This study provides evidence that de novo heterozygous ATP6V1A mutations cause a developmental encephalopathy with a pathomechanism that involves perturbations of lysosomal homeostasis and neuronal connectivity, uncovering a novel role for v-ATPase in neuronal development.

Sensorimotor and Neurocognitive Dysfunctions Parallel Early Telencephalic Neuropathology in Fucosidosis Mice.

Fucosidosis is a lysosomal storage disorder (LSD) caused by lysosomal α-L-fucosidase deficiency. Insufficient α-L-fucosidase activity triggers accumulation of undegraded, fucosylated glycoproteins and glycolipids in various tissues. The human phenotype is heterogeneous, but progressive motor and cognitive impairments represent the most characteristic symptoms. Recently, Fuca1-deficient mice were generated by gene targeting techniques, constituting a novel animal model for human fucosidosis. These mice display widespread LSD pathology, accumulation of secondary storage material and neuroinflammation throughout the brain, as well as progressive loss of Purkinje cells. Fuca1-deficient mice and control littermates were subjected to a battery of tests detailing different aspects of motor, emotional and cognitive function. At an early stage of disease, we observed reduced exploratory activity, sensorimotor disintegration as well as impaired spatial learning and fear memory. These early markers of neurological deterioration were related to the respective stage of neuropathology using molecular genetic and immunochemical procedures. Increased expression of the lysosomal marker Lamp1 and neuroinflammation markers was observed throughout the brain, but appeared more prominent in cerebral areas in comparison to cerebellum of Fuca1-deficient mice. This is consistent with impaired behaviors putatively related to early disruptions of motor and cognitive circuits particularly involving cerebral cortex, basal ganglia, and hippocampus. Thus, Fuca1-deficient mice represent a practical and promising fucosidosis model, which can be utilized for pathogenetic and therapeutic studies.

17β-Estradiol on the Expression of G-Protein Coupled Estrogen Receptor (GPER/GPR30) Mitophagy, and the PI3K/Akt Signaling Pathway in ATDC5 Chondrocytes In Vitro.

BackgroundOsteoarthritis is a progressive inflammatory joint disease resulting in damage to articular cartilage. G-protein coupled estrogen receptor (GPER/GPR30) activates cell signaling in response to 17β-estradiol, which can be blocked by the GPR30 agonist, G15, an analog of G-1. The aims of this study were to investigate the effects of 17β-estradiol on the expression of G-protein coupled estrogen receptor (GPER/GPR30) on mitophagy and the PI3K/Akt signaling pathway in ATDC5 chondrocytes in vitro.Material/MethodsCultured ATDC5 chondrocytes were treated with increasing concentrations of 17β-estradiol with and without G15, p38 inhibitor (SB203580), JNK inhibitor (SP600125), PI3K inhibitor (LY294002, S1737), and mTOR inhibitor (S1842). Expression of GPER/GPR30 and components of the PI3K/Akt pathway in cultured ATDC5 chondrocytes were detected by immunofluorescence (IF) staining, Western blot, and real-time polymerase chain reaction (RT-PCR). Transmission electron microscopy (TEM) and IF were used to detect mitophagosomes. Expression of LC-3, LAMP2, TOM20, Hsp60, p-Akt, p-mTOR, p-p38, and p-JNK was investigated by Western blot. Proliferation and viability of the ATDC5 chondrocytes were determined using BrdU and MTT assays.ResultsIn 17β-estradiol-treated ATDC5 chondrocytes, increased expression of GPER/GPR30 was found, but fewer mitophagosomes were observed, and decreased numbers of TOM20-positive granules were co-localized with decreased LAMP2 and increased expression levels of TOM20, Hsp60, p-Akt, and p-mTOR, and reduced expression of LC3-II, were found. In 17β-estradiol-treated ATDC5 chondrocytes, the proliferation and viability of the 17β-estradiol-treated ATDC5 chondrocytes were significantly elevated.ConclusionsTreatment with 17β-estradiol protected ATDC5 chondrocytes against mitophagy via the GPER/GPR30 and the PI3K/Akt signaling pathway.

Mannose receptor (MR) and Toll-like receptor 2 (TLR2) influence phagosome maturation during Leishmania infection.

Leishmania enter macrophages through receptor-mediated phagocytosis and survive the harsh environment of a phagolysosome. Here, we investigated the interaction between mannose receptor (MR), Toll-like receptor 2 (TLR2), and Leishmania, and the subsequent impact on phagosome maturation. Leishmania parasites are able to delay phagosome maturation, not reaching full maturation until 5hours post-engulfment. Here, maturation of Leishmania major- and Leishmania donovani-containing phagosomes proceeded as expected in the WT macrophages becoming LAMP1 positive by 6hours. Interestingly, MR-/- macrophages become LAMP1 positive by ~2hours and ~4hours post-infection Leishmania-containing phagosomes lost LAMP1 expression and gained the early marker EEA1. LAMP1 expression was again observed by 6hours. Leishmania LPG was essential for the delay in both WT and MR-/- macrophages but was not essential for the early maturation (2hours) observed in MR-/- macrophages. Serum opsonization of Leishmania prior to infection induced identical phagosome maturation patterns in WT and MR-/- macrophages. In the absence of MyD88 or TLR2 on macrophages, Leishmania phagosomes matured significantly faster, becoming LAMP1 positive by ~1-2hours. These studies add to the knowledge that phagosome maturation is influenced by multiple receptor-ligand interactions and signalling pathways.

19q13.12 microdeletion syndrome fibroblasts display abnormal storage of cholesterol and sphingolipids in the endo-lysosomal system

Microdeletions in 19q12q13.12 cause a rare and complex haploinsufficiency syndrome characterized by intellectual deficiency, developmental delays, and neurological movement disorders. Variability in the size and interval of the deletions makes it difficult to attribute the complex clinical phenotype of this syndrome to an underlying gene(s). As an alternate approach, we examined the biochemical and metabolic features of fibroblasts from an affected individual to derive clues as to the molecular basis for the syndrome. Immunofluorescence and electron microscopy of affected fibroblasts revealed an abnormal endo-lysosomal compartment that was characterized by rapid accumulation of lysosomotropic dyes, elevated LAMP1 and LAMP2 expression and vacuoles containing membrane whorls, common features of lysosomal lipid storage disorders. The late endosomes-lysosomes (LE/LY) of affected fibroblasts accumulated low-density lipoprotein cholesterol, and displayed reduced cholesterol esterification and increased de novo cholesterol synthesis, indicative of defective cholesterol transport to the endoplasmic reticulum. Affected fibroblasts also had increased ceramide and sphingolipid mass, altered glycosphingolipid species and accumulation of a fluorescent lactosylceramide probe in LE/LY. Autophagosomes also accumulated in affected fibroblasts because of decreased fusion with autolysosomes, a defect associated with other lysosomal storage diseases. Attempts to correct the cholesterol/sphingolipid storage defect in fibroblasts with cyclodextrin, sphingolipid synthesis inhibitors or by altering ion transport were unsuccessful. Our data show that 19q13.12 deletion fibroblasts have abnormal accumulation of cholesterol and sphingolipids in the endo-lysosomal system that compromises organelle function and could be an underlying cause of the clinical features of the syndrome.

Autophagy- and MMP-2/9-mediated Reduction and Redistribution of ZO-1 Contribute to Hyperglycemia-increased Blood–Brain Barrier Permeability During Early Reperfusion in Stroke

Post-stroke hyperglycemia during early reperfusion increases blood–brain barrier (BBB) permeability and subsequently aggravates brain injury and clinical prognosis. The decreased level of tight junction proteins (TJPs) has been reported but the underlying mechanism remains largely elusive. Herein we designed to investigate the detailed molecular events in brain microvascular endothelial cells (BMECs) ex and in vivo. After oxygen–glucose deprivation (OGD) for 90 min and reperfusion with 8 or 16 mM glucose for 30 min, glucose at 16 mM caused significant decrease in the TJP expression and particularly ZO-1 redistribution from membrane to cytoplasm of BMECs. High glucose also markedly promoted the secretion of MMP-2/9 and oxidative/nitrosative stress, enhanced autophagy and increased the Caveolin-1 and LAMP-2 expression. Moreover, in vivo experiments demonstrated that rapamycin-enhanced autophagy further caused ZO-1 reduction and the increased BBB permeability. Therefore, high-glucose exposure in the early reperfusion causes the BBB disruption, with MMP-2/9-mediated extracellular degradation, caveolin-1-mediated intracellular translocation and autophagy-lysosome-mediated degradation of ZO-1 protein all together involved in the process. The role of MMP-2/-9 and autophagy in the modulation of paracellular permeability was confirmed by pharmacological inhibition. Therefore, our findings may provide new insights into targeting ZO-1 regulation for the purpose of significantly improving the clinical prognosis of ischemic stroke.

Effects of ovarian hormone loss on neuritic plaques and autophagic flux in the brains of adult female APP/PS1 double-transgenic mice.

Epidemiologic studies have demonstrated that women account for two-thirds of Alzheimer’s disease (AD) cases, for which the decline in circulating gonadal hormone is considered to be one of the major risk factors. In addition, ovarian hormone deficiency may affect β-amyloid (Aβ) deposition, which has a close relationship with autophagic flux. In this study, we investigated the impact of short-term or long-term ovarian hormone deprivation on two mouse models, the non-transgenic (wild-type) and the APP/PS1 double-transgenic AD (2×TgAD) model. Autophagy-related proteins (Beclin1, LC3, and p62) and lysosome-related proteins were detected to evaluate Aβ deposition and autophagy. Our results showed that in the group with short-term depletion of ovarian hormones by ovariectomy (ovx), Beclin1, Cathepsin B (Cath-B), and LAMP1 levels were significantly decreased, while the levels of LC3-II and p62 were increased. In the long-term group, however, there was a sharp decline in Beclin1, LC3-II, Cath-B, and LAMP1 expression but not in p62 expression which is increased. It is worthwhile to note that the occurrence of neuritic plaque-induced ovarian hormone loss increased both the Aβ level and neuritic plaque deposition in 2×TgAD mice. Therefore, autophagy may play an important role in the pathogenesis of female AD, which is also expected to help post-menopausal patients with AD.