Microglial Pdcd4 deficiency mitigates neuroinflammation-associated depression via facilitating Daxx mediated PPARγ/IL-10 signaling.

The dysregulation of pro- and anti-inflammatory processes in the brain has been linked to the pathogenesis of major depressive disorder (MDD), although the precise mechanisms remain unclear. In this study, we discovered that microglial conditional knockout of Pdcd4 conferred protection against LPS-induced hyperactivation of microglia and depressive-like behavior in mice. Mechanically, microglial Pdcd4 plays a role in promoting neuroinflammatory responses triggered by LPS by inhibiting Daxx-mediated PPARγ nucleus translocation, leading to the suppression of anti-inflammatory cytokine IL-10 expression. Finally, the antidepressant effect of microglial Pdcd4 knockout under LPS-challenged conditions was abolished by intracerebroventricular injection of the IL-10 neutralizing antibody IL-10Rα. Our study elucidates the distinct involvement of microglial Pdcd4 in neuroinflammation, suggesting its potential as a therapeutic target for neuroinflammation-related depression.

The scaffold protein disabled 2 (DAB2) and its role in tumor development and progression.

BACKGROUND: Disabled 2 (DAB2) is a multifunctional protein that has emerged as a critical component in the regulation of tumor growth. Its dysregulation is implicated in various types of cancer, underscoring its importance in understanding the molecular mechanisms underlying tumor development and progression. This review aims to unravel the intricate molecular mechanisms by which DAB2 exerts its tumor-suppressive functions within cancer signaling pathways. METHODS AND RESULTS: We conducted a comprehensive review of the literature focusing on the structure, expression, physiological functions, and tumor-suppressive roles of DAB2. We provide an overview of the structure, expression, and physiological functions of DAB2. Evidence supporting DAB2's role as a tumor suppressor is explored, highlighting its ability to inhibit cell proliferation, induce apoptosis, and modulate key signaling pathways involved in tumor suppression. The interaction between DAB2 and key oncogenes is examined, elucidating the interplay between DAB2 and oncogenic signaling pathways. We discuss the molecular mechanisms underlying DAB2-mediated tumor suppression, including its involvement in DNA damage response and repair, regulation of cell cycle progression and senescence, and modulation of epithelial-mesenchymal transition (EMT). The review explores the regulatory networks involving DAB2, covering post-translational modifications, interactions with other tumor suppressors, and integration within complex signaling networks. We also highlight the prognostic significance of DAB2 and its role in pre-clinical studies of tumor suppression. CONCLUSION: This review provides a comprehensive understanding of the molecular mechanisms by which DAB2 exerts its tumor-suppressive functions. It emphasizes the significance of DAB2 in cancer signaling pathways and its potential as a target for future therapeutic interventions.

In vivo and in vitro studies on the role of regulating Smac expression in the occurrence and development of colon cancer.

We aimed to explore the role of regulating Smac expression levels in the occurrence and development of colon cancer through in vitro and in vivo experiments. Colon cancer cells HT-29 were cultured and transfected into different groups. qRT-PCR was used to detect the expression level of Smac in cells; Flow cytometry was used to detect the apoptotic ability of each group of cells; Western blot was used to detect the protein expression of Smac and apoptosis-related factors Survivin and Caspase-3; The nude mouse tumorigenesis experiment was conducted to detect the regulatory effect of regulating Smac expression levels on the growth of colon cancer transplanted tumors in vivo. In comparison to the FHC group, the HT-29 group exhibited a decrease in Smac expression. The si-Smac group, when compared with the si-NC group, showed significant reductions in Smac mRNA and protein levels, weaker cell apoptosis, increased Survivin, and decreased Caspase-3 expression. Contrarily, the oe-Smac group, against the oe-NC group, displayed increased Smac mRNA and protein levels, enhanced apoptosis, reduced Survivin, and elevated Caspase-3 expression. In nude mice tumor transplantation experiments, the LV-sh-Smac group, as opposed to the LV-sh-NC group, had tumors with greater volume and weight, reduced Smac and Caspase-3, and increased Survivin expression. In contrast, the LV-oe-Smac group, compared with the LV-oe-NC group, showed tumors with decreased volume and mass, increased expressions of Smac and Caspase-3, and decreased Survivin. Smac is lowly expressed in colon cancer. Upregulation of Smac expression can inhibit the occurrence and development of colon cancer, possibly by inhibiting Survivin expression and promoting Caspase-3 expression, thereby enhancing the pro-apoptotic function.

Enhancing ASPP2 promotes acute liver injury via an inflammatory immunoregulatory mechanism.

Background: Acute liver injury (ALI), which is a type of inflammation-mediated hepatocellular injury, is a clinical syndrome that results from hepatocellular apoptosis and hemorrhagic necrosis. Apoptosis stimulating protein of p53-2 (ASPP2) is a proapoptotic member of the p53 binding protein family. However, the role of ASPP2 in the pathogenesis of ALI and its regulatory mechanisms remain unclear. Methods: The expression of ASPP2 were compared between liver biopsies derived from patients with CHB, patients with ALI, and normal controls. Acute liver injury was modelled in mice by administration of D-GalN/LPS. Liver injury was demonstrated by serum transaminases and histological assessment of liver sections. ASPP2-knockdown mice (ASPP2+/-) were used to determine its role in acute liver injury. Mouse bone marrow macrophages (BMMs) were isolated from wildtype and ASPP2+/- mice and stimulated with LPS, and the supernatant was collected to incubate with the primary hepatocytes. Quantitative real-time PCR and western blot were used to analyze the expression level of target. Results: The expression of ASPP2 was significantly upregulated in the liver tissue of ALI patients and acute liver injury mice. ASPP2+/- mice significantly relieved liver injury through reducing liver inflammation and decreasing hepatocyte apoptosis. Moreover, the conditioned medium (CM) of ASPP2+/- bone marrow-derived macrophages (BMMs) protected hepatocytes against apoptosis. Mechanistically, we revealed that ASPP2 deficiency in BMMs specifically upregulated IL-6 through autophagy activation, which decreased the level of TNF-α to reduce hepatocytes apoptosis. Furthermore, up-regulation of ASPP2 sensitizes hepatocytes to TNF-α-induced apoptosis. Conclusion: Our novel findings show the critical role of ASPP2 in inflammatory immunoregulatory mechanism of ALI and provide a rationale to target ASPP2 as a refined therapeutic strategy to ameliorate acute liver injury.

Dermaseptin B2 bioactive gene's potential for anticancer and anti-proliferative effect is linked to the regulation of the BAX/BBC3/AKT pathway.

Dermaseptin B2 (DrsB2) is an antimicrobial peptide with anticancer and angiostatic properties. We aimed to assess the in vitro inhibitory effect of pDNA/DrsB2 on the growth of breast cancer cells and its impact on the expression of genes involved in the BAX/BBC3/AKT pathway. The nucleic acid sequence of DrsB2 was artificially synthesized and inserted into the pcDNA3.1( +) Mammalian Expression Plasmid. PCR testing and enzyme digesting procedures evaluated the accuracy of cloning. The vectors were introduced into cells using LipofectamineTM2000 transfection reagent. The breast cancer cells were assessed by flow cytometry, MTT assessment, soft agar colony method, and wound healing investigation. The gene's transcription was evaluated using real-time PCR with a significance level of P < 0.05. The recombinant plasmid harboring the pDNA/DrsB2 vector was effectively produced, and the gene sequence showed absolute homogeneity (100% similarity) with the DrsB2 gene. The transfection effectiveness of MCF-7 and MCF-10A cells was 79% and 68%, respectively. The findings are measured using the growth inhibition 50% (GI50) metric, which indicates the concentration of pDNA/DrsB2 that stops 50% of cell growth. The proportions of early apoptosis, late apoptosis, necrosis, and viable MCF-7 cells in the pDNA/DrsB2 group were 40.50%, 2.31%, 1.69%, and 55.50%, respectively. The results showed a 100% increase in gene expression in programmed cell death following treatment with pDNA/DrsB2 (**P < 0.01). To summarize, the results described in this work offer new possibilities for treating cancer by targeting malignancies via pDNA/DrsB2 and activating the BAX/BBC3/AKT signaling pathways.

Dab2 (Disabled-2), an adaptor protein, regulates self-renewal of hair follicle stem cells.

Disabled 2 (Dab2), an adaptor protein, is up regulated in the hair follicle stem cells (HFSCs); however, its role in any tissue stem cells has not been studied. In the present study, we have reported that Dab2 conditional knockout (Dab2-cKO) mice exhibited a delay in the HF cycle due to perturbed activation of HFSCs. Further, Dab2-cKO mice showed a reduction in the number of HFSCs and reduced colony forming ability of HFSCs. Dab2-cKO mice showed extended quiescence of HFSCs concomitant with an increased expression of Nfatc1. Dab2-cKO mice showed a decreased expression of anti-aging genes such as Col17a1, decorin, Sirt2 and Sirt7. Dab2-cKO mice did not show full hair coat recovery in aged mice thereby suggesting an accelerated aging process. Overall, we unveil for the first time, the role of Dab2 that regulate activation and self-renewal of HFSCs.

Disruption of TIGAR-TAK1 alleviates immunopathology in a murine model of sepsis.

Macrophage-orchestrated inflammation contributes to multiple diseases including sepsis. However, the underlying mechanisms remain to be defined clearly. Here, we show that macrophage TP53-induced glycolysis and apoptosis regulator (TIGAR) is up-regulated in murine sepsis models. When myeloid Tigar is ablated, sepsis induced by either lipopolysaccharide treatment or cecal ligation puncture in male mice is attenuated via inflammation inhibition. Mechanistic characterizations indicate that TIGAR directly binds to transforming growth factor ß-activated kinase (TAK1) and promotes tumor necrosis factor receptor-associated factor 6-mediated ubiquitination and auto-phosphorylation of TAK1, in which residues 152-161 of TIGAR constitute crucial motif independent of its phosphatase activity. Interference with the binding of TIGAR to TAK1 by 5Z-7-oxozeaenol exhibits therapeutic effects in male murine model of sepsis. These findings demonstrate a non-canonical function of macrophage TIGAR in promoting inflammation, and confer a potential therapeutic target for sepsis by disruption of TIGAR-TAK1 interaction.

Variant-to-function analysis of the childhood obesity chr12q13 locus implicates rs7132908 as a causal variant within the 3' UTR of FAIM2.

The ch12q13 locus is among the most significant childhood obesity loci identified in genome-wide association studies. This locus resides in a non-coding region within FAIM2; thus, the underlying causal variant(s) presumably influence disease susceptibility via cis-regulation. We implicated rs7132908 as a putative causal variant by leveraging our in-house 3D genomic data and public domain datasets. Using a luciferase reporter assay, we observed allele-specific cis-regulatory activity of the immediate region harboring rs7132908. We generated isogenic human embryonic stem cell lines homozygous for either rs7132908 allele to assess changes in gene expression and chromatin accessibility throughout a differentiation to hypothalamic neurons, a key cell type known to regulate feeding behavior. The rs7132908 obesity risk allele influenced expression of FAIM2 and other genes and decreased the proportion of neurons produced by differentiation. We have functionally validated rs7132908 as a causal obesity variant that temporally regulates nearby effector genes and influences neurodevelopment and survival.

HIF3A gene disruption causes abnormal alveoli structure and early neonatal death.

Transcriptional response to changes in oxygen concentration is mainly controlled by hypoxia-inducible transcription factors (HIFs). Besides regulation of hypoxia-responsible gene expression, HIF-3α has recently been shown to be involved in lung development and in the metabolic process of fat tissue. However, the precise mechanism for such properties of HIF-3α is still largely unknown. To this end, we generated HIF3A gene-disrupted mice by means of genome editing technology to explore the pleiotropic role of HIF-3α in development and physiology. We obtained adult mice carrying homozygous HIF3A gene mutations with comparable body weight and height to wild-type mice. However, the number of litters and ratio of homozygous mutation carriers born from the mating between homozygous mutant mice was lower than expected due to sporadic deaths on postnatal day 1. HIF3A gene-disrupted mice exhibited abnormal configuration of the lung such as a reduced number of alveoli and thickened alveolar walls. Transcriptome analysis showed, as well as genes associated with lung development, an upregulation of stearoyl-Coenzyme A desaturase 1, a pivotal enzyme for fatty acid metabolism. Analysis of fatty acid composition in the lung employing gas chromatography indicated an elevation in palmitoleic acid and a reduction in oleic acid, suggesting an imbalance in distribution of fatty acid, a constituent of lung surfactant. Accordingly, administration of glucocorticoid injections during pregnancy resulted in a restoration of normal alveolar counts and a decrease in neonatal mortality. In conclusion, these observations provide novel insights into a pivotal role of HIF-3α in the preservation of critically important structure and function of alveoli beyond the regulation of hypoxia-mediated gene expression.

Therapeutic targeting of ARID1A-deficient cancer cells with RITA (Reactivating p53 and inducing tumor apoptosis).

ARID1A, a component of the SWI/SNF chromatin-remodeling complex, is frequently mutated in various cancer types and has emerged as a potential therapeutic target. In this study, we observed that ARID1A-deficient colorectal cancer (CRC) cells showed synthetic lethal effects with a p53 activator, RITA (reactivating p53 and inducing tumor apoptosis). RITA, an inhibitor of the p53-MDM2 interaction, exhibits increased sensitivity in ARID1A-deficient cells compared to ARID1A wild-type cells. Mechanistically, the observed synthetic lethality is dependent on both p53 activation and DNA damage accumulation, which are regulated by the interplay between ARID1A and RITA. ARID1A loss exhibits an opposing effect on p53 targets, leading to decreased p21 expression and increased levels of proapoptotic genes, PUMA and NOXA, which is further potentiated by RITA treatment, ultimately inducing cell apoptosis. Meanwhile, ARID1A loss aggravates RITA-induced DNA damage accumulation by downregulating Chk2 phosphorylation. Taken together, ARID1A loss significantly heightens sensitivity to RITA in CRC, revealing a novel synthetic lethal interaction between ARID1A and RITA. These findings present a promising therapeutic approach for colorectal cancer characterized by ARID1A loss-of-function mutations.

Clinically relevant GABARAP deficiency abrogates bortezomib-induced immunogenic cell death in multiple myeloma.

Recently, it was revealed that the high-risk, poor-prognosis downregulation of GABA type A receptor-associated protein (GABARAP) causes a defect in both autophagy and surface exposure of calreticulin (CALR) in multiple myeloma (MM) cells responding to bortezomib. Hence, GABARAP-defective MM cells fail to undergo immunogenic cell death.

Interaction of SMAC with a survivin-derived peptide alters essential cancer hallmarks: Tumor growth, inflammation, and immunosuppression.

Second mitochondrial-derived activator of caspase (SMAC), also known as direct inhibitor of apoptosis-binding proteins with low pI (Diablo), is known as a pro-apoptotic mitochondrial protein released into the cytosol in response to apoptotic signals. We recently reported SMAC overexpression in cancers as essential for cell proliferation and tumor growth due to non-apoptotic functions, including phospholipid synthesis regulation. These functions may be associated with its interactions with partner proteins. Using a peptide array with 768 peptides derived from 11 selected SMAC-interacting proteins, we identified SMAC-interacting sequences. These SMAC-binding sequences were produced as cell-penetrating peptides targeted to the cytosol, mitochondria, or nucleus, inhibiting cell proliferation and inducing apoptosis in several cell lines. For in vivo study, a survivin/baculoviral inhibitor of apoptosis repeat-containing 5 (BIRC5)-derived peptide was selected, due to its overexpression in many cancers and its involvement in mitosis, apoptosis, autophagy, cell proliferation, inflammation, and immune responses, as a target for cancer therapy. Specifically, a SMAC-targeting survivin/BIRC5-derived peptide, given intratumorally or intravenously, strongly inhibited lung tumor growth, cell proliferation, angiogenesis, and inflammation, induced apoptosis, and remodeled the tumor microenvironment. The peptide promoted tumor infiltration of CD-8+ cells and increased cell-intrinsic programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) expression, resulting in cancer cell self-destruction and increased tumor cell death, preserving immune cells. Thus, targeting the interaction between the multifunctional proteins SMAC and survivin represents an innovative therapeutic cancer paradigm.

BAG3 promotes proliferation and migration of arterial smooth muscle cells by regulating STAT3 phosphorylation in diabetic vascular remodeling.

BACKGROUND: Diabetic vascular remodeling is the most important pathological basis of diabetic cardiovascular complications. The accumulation of advanced glycation end products (AGEs) caused by elevated blood glucose promotes the proliferation and migration of vascular smooth muscle cells (VSMCs), leading to arterial wall thickening and ultimately vascular remodeling. Therefore, the excessive proliferation and migration of VSMCs is considered as an important therapeutic target for vascular remodeling in diabetes mellitus. However, due to the lack of breakthrough in experiments, there is currently no effective treatment for the excessive proliferation and migration of VSMCs in diabetic patients. Bcl-2-associated athanogene 3 (BAG3) protein is a multifunctional protein highly expressed in skeletal muscle and myocardium. Previous research has confirmed that BAG3 can not only regulate cell survival and apoptosis, but also affect cell proliferation and migration. Since the excessive proliferation and migration of VSMCs is an important pathogenesis of vascular remodeling in diabetes, the role of BAG3 in the excessive proliferation and migration of VSMCs and its molecular mechanism deserve further investigation. METHODS: In this study, BAG3 gene was manipulated in smooth muscle to acquire SM22αCre; BAG3FL/FL mice and streptozotocin (STZ) was used to simulate diabetes. Expression of proteins and aortic thickness of mice were detected by immunofluorescence, ultrasound and hematoxylin-eosin (HE) staining. Using human aorta smooth muscle cell line (HASMC), cell viability was measured by CCK-8 and proliferation was measured by colony formation experiment. Migration was detected by transwell, scratch experiments and Phalloidin staining. Western Blot was used to detect protein expression and Co-Immunoprecipitation (Co-IP) was used to detect protein interaction. RESULTS: In diabetic vascular remodeling, AGEs could promote the interaction between BAG3 and signal transducer and activator of transcription 3 (STAT3), leading to the enhanced interaction between STAT3 and Janus kinase 2 (JAK2) and reduced interaction between STAT3 and extracellular signal-regulated kinase 1/2 (ERK1/2), resulting in accumulated p-STAT3(705) and reduced p-STAT3(727). Subsequently, the expression of matrix metallopeptidase 2 (MMP2) is upregulated, thus promoting the migration of VSMCs. CONCLUSIONS: BAG3 upregulates the expression of MMP2 by increasing p-STAT3(705) and decreasing p-STAT3(727) levels, thereby promoting vascular remodeling in diabetes. This provides a new orientation for the prevention and treatment of diabetic vascular remodeling.

Progress on the relationship between tumor suppressor PDCD4 and diseases based on the analysis of structural characteristics.

The tumor suppressor programmed cell death 4 (PDCD4) is downregulated in various tumor tissues indicating poor prognosis. PDCD4 is the first protein found to resist tumor transformation, invasion, and metastasis by inhibiting translation. The functions of PDCD4 dependent on its structures are affected by extracellular signals. It regulates tumor-related proteins through a variety of mechanisms, especially involved in two major signaling pathways, PI3K-Akt-mTOR and MAPK. By analyzing the relationship between the structures, functions and diseases of PDCD4, this review summarizes the roles of PDCD4 in several physiological processes and diseases such as apoptosis, autophagy, tumor, and inflammation in recent years, thereby providing insights for the study of the signaling pathways of PDCD4 and related proteins and the treatment of diseases targeting them.

PDCD4-induced oxidative stress through FGR/NF-κB axis in rectal cancer radiotherapy-induced AKI.

This study aimed to investigate the molecular mechanism of the effect of PDCD4 on radiotherapy-induced acute kidney injury (AKI) in rectal cancer through the regulation of FGR/NF-κB signaling. Differentially expressed genes were identified using Gene Expression Omnibus (GEO) datasets (GSE90627 for rectal cancer and GSE145085 for AKI) and R software. The human renal tubular epithelial cell line, HK-2, was used to establish an in vitro model of radiotherapy-induced AKI. RT-qPCR and western blotting were used to detect gene and protein expression levels, respectively. Cell proliferation and apoptosis were assessed using the CCK-8 assay and flow cytometry, respectively. The malondialdehyde and superoxide dismutase levels in the cell culture supernatants were determined. Additionally, an in vivo AKI model was established using BALB/c mice, and kidney tissue morphology, expression of the renal injury molecule KIM-1, apoptosis of renal tubular cells, and TAS and TOS in serum were evaluated. Bioinformatics analysis revealed the upregulated expression of PDCD4 in AKI. In vitro experiments demonstrated that PDCD4 induced apoptosis in renal tubular cells by promoting FGR expression, which activated the NF-κB signaling pathway and triggered an oxidative stress response. In vivo animal experiments confirmed that PDCD4 promoted oxidative stress response and radiotherapy-induced AKI through the activation of the FGR/NF-κB signaling pathway. Silencing PDCD4 attenuated radiotherapy-induced AKI. Our findings suggest that PDCD4 may induce radiotherapy-induced AKI in rectal cancer by promoting FGR expression, activating the NF-κB signaling pathway, and triggering an oxidative stress response.

Nlrp2 deletion ameliorates kidney damage in a mouse model of cystinosis.

Cystinosis is a rare autosomal recessive disorder caused by mutations in the CTNS gene that encodes cystinosin, a ubiquitous lysosomal cystine/H+ antiporter. The hallmark of the disease is progressive accumulation of cystine and cystine crystals in virtually all tissues. At the kidney level, human cystinosis is characterized by the development of renal Fanconi syndrome and progressive glomerular and interstitial damage leading to end-stage kidney disease in the second or third decade of life. The exact molecular mechanisms involved in the pathogenesis of renal disease in cystinosis are incompletely elucidated. We have previously shown upregulation of NLRP2 in human cystinotic proximal tubular epithelial cells and its role in promoting inflammatory and profibrotic responses. Herein, we have investigated the role of NLRP2 in vivo using a mouse model of cystinosis in which we have confirmed upregulation of Nlrp2 in the renal parenchyma. Our studies show that double knock out Ctns-/- Nlrp2-/- animals exhibit delayed development of Fanconi syndrome and kidney tissue damage. Specifically, we observed at 4-6 months of age that animals had less glucosuria and calciuria and markedly preserved renal tissue, as assessed by significantly lower levels of inflammatory cell infiltration, tubular atrophy, and interstitial fibrosis. Also, the mRNA expression of some inflammatory mediators (Cxcl1 and Saa1) and the rate of apoptosis were significantly decreased in 4-6-month old kidneys harvested from Ctns-/- Nlrp2-/- mice compared to those obtained from Ctns-/-mice. At 12-14 months of age, renal histological was markedly altered in both genetic models, although double KO animals had lower degree of polyuria and low molecular weight proteinuria and decreased mRNA expression levels of Il6 and Mcp1. Altogether, these data indicate that Nlrp2 is a potential pharmacological target for delaying progression of kidney disease in cystinosis.

Direct Salmonella injection into enteroid cells allows the study of host-pathogen interactions in the cytosol with high spatiotemporal resolution.

Intestinal epithelial cells (IECs) play pivotal roles in nutrient uptake and in the protection against gut microorganisms. However, certain enteric pathogens, such as Salmonella enterica serovar Typhimurium (S. Tm), can invade IECs by employing flagella and type III secretion systems (T3SSs) with cognate effector proteins and exploit IECs as a replicative niche. Detection of flagella or T3SS proteins by IECs results in rapid host cell responses, i.e., the activation of inflammasomes. Here, we introduce a single-cell manipulation technology based on fluidic force microscopy (FluidFM) that enables direct bacteria delivery into the cytosol of single IECs within a murine enteroid monolayer. This approach allows to specifically study pathogen-host cell interactions in the cytosol uncoupled from preceding events such as docking, initiation of uptake, or vacuole escape. Consistent with current understanding, we show using a live-cell inflammasome reporter that exposure of the IEC cytosol to S. Tm induces NAIP/NLRC4 inflammasomes via its known ligands flagellin and T3SS rod and needle. Injected S. Tm mutants devoid of these invasion-relevant ligands were able to grow in the cytosol of IECs despite the absence of T3SS functions, suggesting that, in the absence of NAIP/NLRC4 inflammasome activation and the ensuing cell death, no effector-mediated host cell manipulation is required to render the epithelial cytosol growth-permissive for S. Tm. Overall, the experimental system to introduce S. Tm into single enteroid cells enables investigations into the molecular basis governing host-pathogen interactions in the cytosol with high spatiotemporal resolution.

Study on the role of CCM3 gene and lead exposure induced neurotoxicity through neurovascular units.

This study aimed to determine the toxic effects of vascular CCM3 gene deficiency and lead (Pb) exposure on the nervous system. Lentiviral transfection was performed to generate a stable strain of brain microvascular endothelial cells with low CCM3 expression. MTT assay assessed the survival rate of cells exposed to Pb, determining the dose and duration of Pb exposure in vitro. Proteomic analysis was performed on the differentially expressed proteins in bEnd3 and HT22 cells and flow cytometry was used to detect cell apoptosis. Finally, urine samples from pregnant and postpartum women were subjected to ICP-MS to detect Pb levels and HPLC to detect neurotransmitter metabolites. Based on the proteomic analysis of bEnd3 (CCM3-/-) cells co-cultured with HT22 cells, it was determined that HT22 cells and CCM3 genes interfered with bEnd3 cell differential proteins,2 including apoptosis and ferroptosis pathways. Electron microscopy observation, ICP-MS iron ion loading detection, and WB determination of protein GPX4 expression confirmed that HT22 cells undergo apoptosis, while bEnd3 cells undergo multiple pathways of iron death and apoptosis regulation. Furthermore, a linear regression model showed the interaction between maternal urine Pb levels, the rs9818496 site of the CCM3 SNP in peripheral blood DNA, and the concentration of the neurotransmitter metabolite 5-HIAA in maternal urine (F=4.198, P < 0.05). bEnd3 cells with CCM3 gene deficiency can induce HT22 cell apoptosis through iron death and apoptosis pathways under Pb exposure in a combined cell culture Pb exposure model, and CCM3 gene deficiency in endothelial cells and Pb exposure interacts with neural cell HT22. Epidemiological studies on maternal and newborn infants further confirmed the interaction between urine Pb levels in mothers and the SNP rs9818496 site of the CCM3 gene in peripheral blood DNA.

ß-Cell-selective regulation of gene expression by nitric oxide.

Nitric oxide is produced at low micromolar levels following the induction of inducible nitric oxide synthase (iNOS) and is responsible for mediating the inhibitory actions of cytokines on glucose-stimulated insulin secretion by islets of Langerhans. It is through the inhibition of mitochondrial oxidative metabolism, specifically aconitase and complex 4 of the electron transport chain, that nitric oxide inhibits insulin secretion. Nitric oxide also attenuates protein synthesis, induces DNA damage, activates DNA repair pathways, and stimulates stress responses (unfolded protein and heat shock) in ß-cells. In this report, the time- and concentration-dependent effects of nitric oxide on the expression of six genes known to participate in the response of ß-cells to this free radical were examined. The genes included Gadd45α (DNA repair), Puma (apoptosis), Hmox1 (antioxidant defense), Hsp70 (heat shock), Chop (UPR), and Ppargc1α (mitochondrial biogenesis). We show that nitric oxide stimulates ß-cell gene expression in a narrow concentration range of ∼0.5-1 µM or levels corresponding to iNOS-derived nitric oxide. At concentrations greater than 1 µM, nitric oxide fails to stimulate gene expression in ß-cells, and this is associated with the inhibition of mitochondrial oxidative metabolism. This narrow concentration range of responses is ß-cell selective, as the actions of nitric oxide in non-ß-cells (α-cells, mouse embryonic fibroblasts, and macrophages) are concentration dependent. Our findings suggest that ß-cells respond to a narrow concentration range of nitric oxide that is consistent with the levels produced following iNOS induction, and that these concentration-dependent actions are selective for insulin-containing cells.

COPII with ALG2 and ESCRTs control lysosome-dependent microautophagy of ER exit sites.

Endoplasmic reticulum exit sites (ERESs) are tubular outgrowths of endoplasmic reticulum that serve as the earliest station for protein sorting and export into the secretory pathway. How these structures respond to different cellular conditions remains unclear. Here, we report that ERESs undergo lysosome-dependent microautophagy when Ca2+ is released by lysosomes in response to nutrient stressors such as mTOR inhibition or amino acid starvation in mammalian cells. Targeting and uptake of ERESs into lysosomes were observed by super-resolution live-cell imaging and focus ion beam scanning electron microscopy (FIB-SEM). The mechanism was ESCRT dependent and required ubiquitinated SEC31, ALG2, and ALIX, with a knockout of ALG2 or function-blocking mutations of ALIX preventing engulfment of ERESs by lysosomes. In vitro, reconstitution of the pathway was possible using lysosomal lipid-mimicking giant unilamellar vesicles and purified recombinant components. Together, these findings demonstrate a pathway of lysosome-dependent ERES microautophagy mediated by COPII, ALG2, and ESCRTS induced by nutrient stress.