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International Immunopharmacology Jun 2024Idiopathic pulmonary fibrosis (IPF) is considered to be associated with aging. Both ER stress and the unfolded protein response (UPR) have been associated with pulmonary...
Idiopathic pulmonary fibrosis (IPF) is considered to be associated with aging. Both ER stress and the unfolded protein response (UPR) have been associated with pulmonary fibrosis via key mechanisms including AEC apoptosis, EMT, altered myofibroblast differentiation, and M2 macrophage polarization. A relationship between ER stress and aging has also been demonstrated in vitro, with increased p16 and p21 levels seen in lung epithelial cells of older IPF patients. The mechanism underlying ER stress regulation of IPF fibroblasts is still unclear. In this study, we aimed to delineate ER stress regulation in IPF-derived fibroblasts. Here, we found that ER stress markers (p-eIF2α, p-IREα, ATF6) and fibrosis markers (α-SMA and Collagen-I) were significantly increased in lung tissues of IPF patients and bleomycin-induced mouse models. Notably, the expression of PGC-1α was decreased in fibroblasts. In vivo experiments were designed using an AAV-6 vector mediated conditional PGC-1α knockout driven by a specific α-SMA promoter. Ablation of PGC-1α expression in fibroblasts promoted ER stress and supported the development of pulmonary fibrosis in a bleomycin-induced mouse model. In another experimental group, mice with conditional knockout of PGC-1α in fibroblasts and injected intraperitoneally with 4-PBA (an endoplasmic reticulum stress inhibitor) were protected from lung fibrosis. We further constructed an AAV-6 vector mediated PGC-1α overexpression model driven by a specific Collagen-I promoter. Overexpression of PGC-1α in fibroblasts suppressed ER stress and attenuated development of pulmonary fibrosis in bleomycin-induced mouse models. Taken together, this study identified PGC-1α as a promising target for developing novel therapeutic options for the treatment of lung fibrosis.
PubMed: 38943974
DOI: 10.1016/j.intimp.2024.112514 -
Journal of Inorganic Biochemistry Jun 2024Recent breakthroughs in cancer immunology have propelled immunotherapy to the forefront of cancer research as a promising treatment approach that harnesses the body's...
Recent breakthroughs in cancer immunology have propelled immunotherapy to the forefront of cancer research as a promising treatment approach that harnesses the body's immune system to effectively identify and eliminate cancer cells. In this study, three novel cyclometalated Ir(III) complexes, Ir1, Ir2, and Ir3, were designed, synthesized, and assessed in vitro for cytotoxic activity against several tumor-derived cell lines. Among these, Ir1 exhibited the highest cytotoxic activity, with an IC value of 0.4 ± 0.1 μM showcasing its significant anticancer potential. Detailed mechanistic analysis revealed that co-incubation of Ir1 with 143B cells led to Ir1 accumulation within mitochondria and the endoplasmic reticulum (ER). Furthermore, Ir1 induced G0/G1 phase cell cycle arrest, while also diminishing mitochondrial membrane potential, disrupting mitochondrial function, and triggering ER stress. Intriguingly, in mice the Ir1-induced ER stress response disrupted calcium homeostasis to thereby trigger immunogenic cell death (ICD), which subsequently activated the host antitumor immune response while concurrently dampening the in vivo tumor-induced inflammatory response.
PubMed: 38943844
DOI: 10.1016/j.jinorgbio.2024.112655 -
Cell Reports Jun 2024The unfolded protein response (UPR) relieves endoplasmic reticulum (ER) stress through multiple strategies, including reducing protein synthesis, increasing protein...
The unfolded protein response (UPR) relieves endoplasmic reticulum (ER) stress through multiple strategies, including reducing protein synthesis, increasing protein folding capabilities, and enhancing misfolded protein degradation. After a multi-omics analysis, we find that signal recognition particle 14 (SRP14), an essential component of the SRP, is markedly reduced in cells undergoing ER stress. Further experiments indicate that SRP14 reduction requires PRKR-like ER kinase (PERK)-mediated eukaryotic translation initiation factor 2α (eIF2α) phosphorylation but is independent of ATF4 or ATF3 transcription factors. The decrease of SRP14 correlates with reduced translocation of fusion proteins and endogenous cathepsin D. Enforced expression of an SRP14 variant with elongation arrest capability prevents the reduced translocation of cathepsin D in stressed cells, whereas an SRP14 mutant without the activity does not. Finally, overexpression of SRP14 augments the UPR and aggravates ER-stress-induced cell death. These data suggest that translocational attenuation mediated by the PERK-SRP14 axis is a protective measure for the UPR to mitigate ER stress.
PubMed: 38943644
DOI: 10.1016/j.celrep.2024.114402 -
Molekuliarnaia Biologiia 2024Melatonin (N-acetyl-5-methoxytryptamine, MEL) is a hormone synthesized by the pineal gland. Due to its oncostatic effect, it can be considered as an antitumor agent and...
Melatonin (N-acetyl-5-methoxytryptamine, MEL) is a hormone synthesized by the pineal gland. Due to its oncostatic effect, it can be considered as an antitumor agent and used for combination therapy. ABT-737, a Bcl-2 inhibitor, promotes cell death after treatment with agents that induce pro-apoptotic signals. In the present study, the combined effect of MEL and ABT-737 on changes in proliferative and mitotic activity, mitochondrial membrane potential, intracellular production of reactive oxygen species (ROS), and cytosolic Ca^(2+) was studied. Moreover, changes in the expression of anti- and pro-apoptotic proteins (Bcl-2 and Bax), autophagy markers (LC3A/B (I, II)), endoplasmic reticulum stress markers (chaperones BIP and PDI, CHOP) were studied under these conditions. The effect of MEL together with ABT-737 led to an increase in the level of cytosolic Ca^(2+), intracellular production of ROS and a decrease in the membrane potential of mitochondria. The content of Bcl-2 increased, while the level of Bax decreased. Activation of CHOP stimulated autophagy and led to a decrease in the synthesis of chaperones BIP and PDI. It is assumed that melatonin can enhance the effect of other chemotherapeutic agents and can be used in the treatment of tumors.
Topics: Humans; Sulfonamides; Melatonin; Nitrophenols; Piperazines; Biphenyl Compounds; Reactive Oxygen Species; Membrane Potential, Mitochondrial; Apoptosis; Proto-Oncogene Proteins c-bcl-2; THP-1 Cells; bcl-2-Associated X Protein; Drug Synergism; Autophagy; Endoplasmic Reticulum Stress; Endoplasmic Reticulum Chaperone BiP; Cell Proliferation; Microtubule-Associated Proteins; Calcium; Neoplasm Proteins; Transcription Factor CHOP
PubMed: 38943585
DOI: No ID Found -
Acta Pharmacologica Sinica Jun 2024C/EBP homologous protein (CHOP) triggers the death of multiple cancers via endoplasmic reticulum (ER) stress. However, the function and regulatory mechanism of CHOP in...
C/EBP homologous protein (CHOP) triggers the death of multiple cancers via endoplasmic reticulum (ER) stress. However, the function and regulatory mechanism of CHOP in liver cancer remain elusive. We have reported that late endosomal/lysosomal adapter, mitogen-activated protein kinase and mTOR activator 5 (LAMTOR5) suppresses apoptosis in various cancers. Here, we show that the transcriptional and posttranscriptional inactivation of CHOP mediated by LAMTOR5 accelerates liver cancer growth. Clinical bioinformatic analysis revealed that the expression of CHOP was low in liver cancer tissues and that its increased expression predicted a good prognosis. Elevated CHOP contributed to destruction of LAMTOR5-induced apoptotic suppression and proliferation. Mechanistically, LAMTOR5-recruited DNA methyltransferase 1 (DNMT1) to the CpG3 region (-559/-429) of the CHOP promoter and potentiated its hypermethylation to block its interaction with general transcription factor IIi (TFII-I), resulting in its inactivation. Moreover, LAMTOR5-enhanced miR-182/miR-769 reduced CHOP expression by targeting its 3'UTR. Notably, lenvatinib, a first-line targeted therapy for liver cancer, could target the LAMTOR5/CHOP axis to prevent liver cancer progression. Accordingly, LAMTOR5-mediated silencing of CHOP via the regulation of ER stress-related apoptosis promotes liver cancer growth, providing a theoretical basis for the use of lenvatinib for the treatment of liver cancer.
PubMed: 38942954
DOI: 10.1038/s41401-024-01310-y -
The Journal of Neuroscience : the... Jun 2024The mechanisms utilized by neurons to regulate the efficacy of phasic and tonic inhibition and their impacts on synaptic plasticity and behavior are incompletely...
Haploinsufficiency of GABA receptor-associated Clptm1 enhances phasic and tonic inhibitory neurotransmission, suppresses excitatory synaptic plasticity, and impairs memory.
The mechanisms utilized by neurons to regulate the efficacy of phasic and tonic inhibition and their impacts on synaptic plasticity and behavior are incompletely understood. Cleft lip and palate transmembrane protein 1 (Clptm1) is a membrane-spanning protein that interacts with multiple γ-aminobutyric acid type A receptor (GABAR) subunits, trapping them in the endoplasmic reticulum and Golgi network. Overexpression and knockdown studies suggest that Clptm1 modulates GABAR-mediated phasic inhibition and tonic inhibition as well as activity-induced inhibitory synaptic homeostasis in cultured hippocampal neurons. To investigate the role of Clptm1 in the modulation of GABARs in vivo, we generated Clptm1 knockout mice. Here, we show that genetic knockout of Clptm1 elevated phasic and tonic inhibitory transmission in both male and female heterozygous mice. Although basal excitatory synaptic transmission was not affected, Clptm1 haploinsufficiency significantly blocked high-frequency stimulation induced long-term potentiation in hippocampal CA3-CA1 synapses. In the hippocampus-dependent contextual fear conditioning behavior task, both male and female Clptm1 heterozygous knockout mice exhibited impairment in contextual fear memory. In addition, LTP and contextual fear memory were rescued by application of L-655,708, a negative allosteric modulator of the extrasynaptic GABAR α5 subunit. These results suggest that haploinsufficiency of Clptm1 contributes to cognitive deficits through altered synaptic transmission and plasticity by elevation of inhibitory neurotransmission, with tonic inhibition playing a major role. The gene was originally identified as disrupted in a family with cleft lip and palate. At the molecular level, Clptm1 interacts with multiple GABA receptor subunits to limit their surface expression. Here, we generated Clptm1 knockout mice to uncover its functions in vivo. Clptm1 not only limited hippocampal inhibitory phasic and tonic transmission, it was required for excitatory synaptic plasticity and hippocampus-dependent cognitive function. A modulator of extrasynaptic GABA receptors rescued the deficits in plasticity and behavior in Clptm1 heterozygous knockout mice, indicating the importance of tonic inhibition. These findings reveal a role for Clptm1 in balancing inhibitory strength and raise the possibility that disruptions of Clptm1 function may contribute to synaptic and cognitive deficits in neurological diseases.
PubMed: 38942471
DOI: 10.1523/JNEUROSCI.0521-24.2024 -
Neurobiology of Disease Jun 2024After ischemic stroke (IS), secondary injury is intimately linked to endoplasmic reticulum (ER) stress and body-brain crosstalk. Nonetheless, the underlying mechanism...
After ischemic stroke (IS), secondary injury is intimately linked to endoplasmic reticulum (ER) stress and body-brain crosstalk. Nonetheless, the underlying mechanism systemic immune disorder mediated ER stress in human IS remains unknown. In this study, 32 candidate ER stress-related genes (ERSRGs) were identified by overlapping MSigDB ER stress pathway genes and DEGs. Three Key ERSRGs (ATF6, DDIT3 and ERP29) were identified using LASSO, random forest, and SVM-RFE. IS patients with different ERSRGs profile were clustered into two groups using consensus clustering and the difference between 2 group was further explored by GSVA. Through immune cell infiltration deconvolution analysis, and middle cerebral artery occlusion (MCAO) mouse scRNA analysis, we found that the expression of 3 key ERSRGs were closely related with peripheral macrophage cell ER stress in IS and this was further confirmed by RT-qPCR experiment. These ERS genes might be helpful to further accurately regulate the central nervous system and systemic immune response through ER stress and have potential application value in clinical practice in IS.
PubMed: 38942324
DOI: 10.1016/j.nbd.2024.106583 -
Ageing Research Reviews Jun 2024Lithium therapy received approval during the 1970s, and it has been used for its antidepressant, antimanic, and anti-suicidal effects for acute and long-term prophylaxis... (Review)
Review
Lithium therapy received approval during the 1970s, and it has been used for its antidepressant, antimanic, and anti-suicidal effects for acute and long-term prophylaxis and treatment of bipolar disorder (BPD). These properties have been well established; however, the molecular and cellular mechanisms remain controversial. In the past few years, many studies demonstrated that at the cellular level, lithium acts as a regulator of neurogenesis, aging, and Ca homeostasis. At the molecular level, lithium modulates aging by inhibiting glycogen synthase kinase-3β (GSK-3β), and the phosphatidylinositol (PI) cycle; latter, lithium specifically inhibits inositol production, acting as a non-competitive inhibitor of inositol monophosphatase (IMPase). Mitochondria and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) have been related to lithium activity, and its regulation is mediated by GSK-3β degradation and inhibition. Lithium also impacts Ca homeostasis in the mitochondria modulating the function of the lithium-permeable mitochondrial Na-Caexchanger (NCLX), affecting Ca efflux from the mitochondrial matrix to the endoplasmic reticulum (ER). A close relationship between the protease Omi, GSK-3β, and PGC-1α has also been established. The purpose of this review is to summarize some of the intracellular mechanisms related to lithium activity and how, through them, neuronal aging could be controlled.
PubMed: 38942199
DOI: 10.1016/j.arr.2024.102396 -
Biomedicine & Pharmacotherapy =... Jun 2024As a broad-spectrum anticancer drug, cisplatin is widely used in the treatment of tumors in various systems. Unfortunately, several serious side effects of cisplatin...
As a broad-spectrum anticancer drug, cisplatin is widely used in the treatment of tumors in various systems. Unfortunately, several serious side effects of cisplatin limit its clinical application, the most common of which are nephrotoxicity and ototoxicity. Studies have shown that cochlear hair cell degeneration is the main cause of cisplatin-induced hearing loss. However, the mechanism of cisplatin-induced hair cell death remains unclear. The present study aimed to explore the potential role of activating transcription factor 6 (ATF6), an endoplasmic reticulum (ER)-localized protein, on cisplatin-induced ototoxicity in vivo and in vitro. In this study, we observed that cisplatin exposure induced apoptosis of mouse auditory OC-1 cells, accompanied by a significant increase in the expression of ATF6 and C/EBP homologous protein (CHOP). In cell or cochlear culture models, treatment with an ATF6 agonist, an ER homeostasis regulator, significantly ameliorated cisplatin-induced cytotoxicity. Further, our in vivo experiments showed that subcutaneous injection of an ATF6 agonist almost completely prevented outer hair cell loss and significantly alleviated cisplatin-induced auditory brainstem response (ABR) threshold elevation in mice. Collectively, our results revealed the underlying mechanism by which activation of ATF6 significantly improved cisplatin-induced hair cell apoptosis, at least in part by inhibiting apoptosis signal-regulating kinase 1 expression, and demonstrated that pharmacological activation of ATF6-mediated unfolded protein response is a potential treatment for cisplatin-induced ototoxicity.
PubMed: 38941893
DOI: 10.1016/j.biopha.2024.117025 -
Analytical Chemistry Jun 2024Several reductases, including nitroreductase, are upregulated under hypoxic conditions characterized by an oxygen-deficient microenvironment. Given that hypoxia is a...
Several reductases, including nitroreductase, are upregulated under hypoxic conditions characterized by an oxygen-deficient microenvironment. Given that hypoxia is a prominent feature of solid tumors, our investigation focused on developing a bioconjugative probe designed for staining tissue under hypoxic conditions, particularly activated by nitroreductase. This probe, developed using our trigger-release-bioconjugation system rooted in the -quinone methide chemistry, exhibited selective activation by nitroreductase and fluorophore labeling within mitochondria and endoplasmic reticulum. As a result, it displayed sustained fluorescence that persisted even after washing steps in cells and tissues. We applied this innovative probe to stain mouse kidney tissue in an acute kidney injury model induced by inadequate oxygen supply. Among various organ tissues examined, only kidney tissue showed significantly higher fluorescence in the injury model compared with the control tissue, as revealed by two-photon microscopic imaging. This research presents a promising avenue for the development of practical staining agents for image-guided tumor surgery.
PubMed: 38940602
DOI: 10.1021/acs.analchem.4c01274