-
International Journal of Medical... 2024Inflammatory responses, apoptosis, and oxidative stress, are key factors that contribute to hepatic ischemia/reperfusion (I/R) injury, which may lead to the failure of...
Inflammatory responses, apoptosis, and oxidative stress, are key factors that contribute to hepatic ischemia/reperfusion (I/R) injury, which may lead to the failure of liver surgeries, such as hepatectomy and liver transplantation. The N6-methyladenosine (mA) modification has been implicated in multiple biological processes, and its specific role and mechanism in hepatic I/R injury require further investigation. Dot blotting analysis was used to profile mA levels in liver tissues at different reperfusion time points in hepatic I/R mouse models. Hepatocyte-specific METTL3 knockdown (HKD) mice were used to determine the function of METTL3 during hepatic I/R. RNA sequencing and western blotting were performed to assess the potential signaling pathways involved with the deficiency of METTL3. Finally, AAV8-TBG-METTL3 was injected through the tail vein to further elucidate the role of METTL3 in hepatic I/R injury. The mA modification levels and the expression of METTL3 were upregulated in mouse livers during hepatic I/R injury. METTL3 deficiency led to an exacerbated inflammatory response and increased cell death during hepatic I/R, whereas overexpression of METTL3 reduced the extent of liver injury. Bioinformatic analysis revealed that the MAPK pathway was significantly enriched in the livers of METTL3-deficient mice. METTL3 protected the liver from I/R injury, possibly by inhibiting the phosphorylation of JNK and ERK, but not P38. METTL3 deficiency aggravates hepatic I/R injury in mice by activating the MAPK signaling pathway. METTL3 may be a potential therapeutic target in hepatic I/R injury.
Topics: Animals; Humans; Male; Mice; Adenosine; Apoptosis; Disease Models, Animal; Hepatocytes; Liver; MAP Kinase Signaling System; Methyltransferases; Mice, Inbred C57BL; Mice, Knockout; Reperfusion Injury; HEK293 Cells
PubMed: 38774758
DOI: 10.7150/ijms.94177 -
Molecular Medicine (Cambridge, Mass.) May 2024Catalpol (CAT) has various pharmacological activities and plays a protective role in cerebral ischemia. It has been reported that CAT played a protective role in...
OBJECTIVE
Catalpol (CAT) has various pharmacological activities and plays a protective role in cerebral ischemia. It has been reported that CAT played a protective role in cerebral ischemia by upregulaing NRF1 expression. Bioinformatics analysis reveals that NRF1 can be used as a transcription factor to bind to the histone acetyltransferase KAT2A. However, the role of KAT2A in cerebral ischemia remains to be studied. Therefore, we aimed to investigate the role of CAT in cerebral ischemia and its related mechanism.
METHODS
In vitro, a cell model of oxygen and glucose deprivation/reperfusion (OGD/R) was constructed, followed by evaluation of neuronal injury and the expression of METTL3, Beclin-1, NRF1, and KAT2A. In vivo, a MCAO rat model was prepared by means of focal cerebral ischemia, followed by assessment of neurological deficit and brain injury in MCAO rats. Neuronal autophagy was evaluated by observation of autophagosomes in neurons or brain tissues by TEM and detection of the expression of LC3 and p62.
RESULTS
In vivo, CAT reduced the neurological function deficit and infarct volume, inhibited neuronal apoptosis in the cerebral cortex, and significantly improved neuronal injury and excessive autophagy in MCAO rats. In vitro, CAT restored OGD/R-inhibited cell viability, inhibited cell apoptosis, LDH release, and neuronal autophagy. Mechanistically, CAT upregulated NRF1, NRF1 activated METTL3 via KAT2A transcription, and METTL3 inhibited Beclin-1 via mA modification.
CONCLUSION
CAT activated the NRF1/KAT2A/METTL3 axis and downregulated Beclin-1 expression, thus relieving neuronal injury and excessive autophagy after cerebral ischemia.
Topics: Animals; Autophagy; Beclin-1; Rats; Neurons; Brain Ischemia; Male; Iridoid Glucosides; Neuroprotective Agents; Disease Models, Animal; Apoptosis; Rats, Sprague-Dawley; Reperfusion Injury; Adenosine
PubMed: 38773376
DOI: 10.1186/s10020-024-00818-7 -
Nature Communications May 2024Epigenetic mechanisms bridge genetic and environmental factors that contribute to the pathogenesis of major depression disorder (MDD). However, the cellular specificity...
Epigenetic mechanisms bridge genetic and environmental factors that contribute to the pathogenesis of major depression disorder (MDD). However, the cellular specificity and sensitivity of environmental stress on brain epitranscriptomics and its impact on depression remain unclear. Here, we found that ALKBH5, an RNA demethylase of N6-methyladenosine (m6A), was increased in MDD patients' blood and depression models. ALKBH5 in astrocytes was more sensitive to stress than that in neurons and endothelial cells. Selective deletion of ALKBH5 in astrocytes, but not in neurons and endothelial cells, produced antidepressant-like behaviors. Astrocytic ALKBH5 in the mPFC regulated depression-related behaviors bidirectionally. Meanwhile, ALKBH5 modulated glutamate transporter-1 (GLT-1) m6A modification and increased the expression of GLT-1 in astrocytes. ALKBH5 astrocyte-specific knockout preserved stress-induced disruption of glutamatergic synaptic transmission, neuronal atrophy and defective Ca activity. Moreover, enhanced m6A modification with S-adenosylmethionine (SAMe) produced antidepressant-like effects. Our findings indicate that astrocytic epitranscriptomics contribute to depressive-like behaviors and that astrocytic ALKBH5 may be a therapeutic target for depression.
Topics: Animals; Astrocytes; AlkB Homolog 5, RNA Demethylase; Mice; Humans; Depressive Disorder, Major; Male; Mice, Knockout; Female; Disease Models, Animal; Mice, Inbred C57BL; Neurons; Stress, Psychological; Adenosine; Excitatory Amino Acid Transporter 2; Behavior, Animal; Prefrontal Cortex; Depression; Adult; Synaptic Transmission; Middle Aged
PubMed: 38773146
DOI: 10.1038/s41467-024-48730-2 -
Nature Communications May 2024Hypomyelinating leukodystrophy (HLD) is an autosomal recessive disorder characterized by defective central nervous system myelination. Exome sequencing of two siblings...
Hypomyelinating leukodystrophy (HLD) is an autosomal recessive disorder characterized by defective central nervous system myelination. Exome sequencing of two siblings with severe cognitive and motor impairment and progressive hypomyelination characteristic of HLD revealed homozygosity for a missense single-nucleotide variant (SNV) in EPRS1 (c.4444 C > A; p.Pro1482Thr), encoding glutamyl-prolyl-tRNA synthetase, consistent with HLD15. Patient lymphoblastoid cell lines express markedly reduced EPRS1 protein due to dual defects in nuclear export and cytoplasmic translation of variant EPRS1 mRNA. Variant mRNA exhibits reduced METTL3 methyltransferase-mediated writing of N-methyladenosine (mA) and reduced reading by YTHDC1 and YTHDF1/3 required for efficient mRNA nuclear export and translation, respectively. In contrast to current models, the variant does not alter the sequence of mA target sites, but instead reduces their accessibility for modification. The defect was rescued by antisense morpholinos predicted to expose mA sites on target EPRS1 mRNA, or by mA modification of the mRNA by METTL3-dCas13b, a targeted RNA methylation editor. Our bioinformatic analysis predicts widespread occurrence of SNVs associated with human health and disease that similarly alter accessibility of distal mRNA mA sites. These results reveal a new RNA-dependent etiologic mechanism by which SNVs can influence gene expression and disease, consequently generating opportunities for personalized, RNA-based therapeutics targeting these disorders.
Topics: Female; Humans; Male; Adenosine; Hereditary Central Nervous System Demyelinating Diseases; Homozygote; Methyltransferases; Mutation, Missense; Nerve Tissue Proteins; RNA Splicing Factors; RNA, Messenger; RNA-Binding Proteins
PubMed: 38769304
DOI: 10.1038/s41467-024-48549-x -
Cell Death & Disease May 2024Osteosarcoma is a malignant bone tumor that primarily inflicts the youth. It often metastasizes to the lungs after chemotherapy failure, which eventually shortens...
Osteosarcoma is a malignant bone tumor that primarily inflicts the youth. It often metastasizes to the lungs after chemotherapy failure, which eventually shortens patients' lives. Thus, there is a dire clinical need to develop a novel therapy to tackle osteosarcoma metastasis. Methionine dependence is a special metabolic characteristic of most malignant tumor cells that may offer a target pathway for such therapy. Herein, we demonstrated that methionine deficiency restricted the growth and metastasis of cultured human osteosarcoma cells. A genetically engineered Salmonella, SGN1, capable of overexpressing an L-methioninase and hydrolyzing methionine led to significant reduction of methionine and S-adenosyl-methionine (SAM) specifically in tumor tissues, drastically restricted the growth and metastasis in subcutaneous xenograft, orthotopic, and tail vein-injected metastatic models, and prolonged the survival of the model animals. SGN1 also sharply suppressed the growth of patient-derived organoid and xenograft. Methionine restriction in the osteosarcoma cells initiated severe mitochondrial dysfunction, as evident in the dysregulated gene expression of respiratory chains, increased mitochondrial ROS generation, reduced ATP production, decreased basal and maximum respiration, and damaged mitochondrial membrane potential. Transcriptomic and molecular analysis revealed the reduction of C1orf112 expression as a primary mechanism underlies methionine deprivation-initiated suppression on the growth and metastasis as well as mitochondrial functions. Collectively, our findings unraveled a molecular linkage between methionine restriction, mitochondrial function, and osteosarcoma growth and metastasis. A pharmacological agent, such as SGN1, that can achieve tumor specific deprivation of methionine may represent a promising modality against the metastasis of osteosarcoma and potentially other types of sarcomas as well.
Topics: Osteosarcoma; Methionine; Humans; Animals; Mitochondria; Cell Line, Tumor; Mice; Bone Neoplasms; Cell Proliferation; Neoplasm Metastasis; S-Adenosylmethionine; Mice, Nude; Reactive Oxygen Species; Gene Expression Regulation, Neoplastic
PubMed: 38769167
DOI: 10.1038/s41419-024-06727-1 -
PLoS Genetics May 2024In many organisms, stress responses to adverse environments can trigger secondary functions of certain proteins by altering protein levels, localization, activity, or...
In many organisms, stress responses to adverse environments can trigger secondary functions of certain proteins by altering protein levels, localization, activity, or interaction partners. Escherichia coli cells respond to the presence of specific cationic antimicrobial peptides by strongly activating the PhoQ/PhoP two-component signaling system, which regulates genes important for growth under this stress. As part of this pathway, a biosynthetic enzyme called QueE, which catalyzes a step in the formation of queuosine (Q) tRNA modification is upregulated. When cellular QueE levels are high, it co-localizes with the central cell division protein FtsZ at the septal site, blocking division and resulting in filamentous growth. Here we show that QueE affects cell size in a dose-dependent manner. Using alanine scanning mutagenesis of amino acids in the catalytic active site, we pinpoint residues in QueE that contribute distinctly to each of its functions-Q biosynthesis or regulation of cell division, establishing QueE as a moonlighting protein. We further show that QueE orthologs from enterobacteria like Salmonella typhimurium and Klebsiella pneumoniae also cause filamentation in these organisms, but the more distant counterparts from Pseudomonas aeruginosa and Bacillus subtilis lack this ability. By comparative analysis of E. coli QueE with distant orthologs, we elucidate a unique region in this protein that is responsible for QueE's secondary function as a cell division regulator. A dual-function protein like QueE is an exception to the conventional model of "one gene, one enzyme, one function", which has divergent roles across a range of fundamental cellular processes including RNA modification and translation to cell division and stress response.
Topics: Escherichia coli; Cell Division; Escherichia coli Proteins; Nucleoside Q; Bacterial Proteins; Klebsiella pneumoniae; Salmonella typhimurium; Gene Expression Regulation, Bacterial; Cytoskeletal Proteins; RNA, Transfer
PubMed: 38768229
DOI: 10.1371/journal.pgen.1011287 -
Journal of Investigative Medicine High... 2024The association between Hairy Cell Leukemia (HCL) and non-tuberculous mycobacterial infections (NTMs) is well described, most notably . The exact pathophysiology is not... (Review)
Review
The association between Hairy Cell Leukemia (HCL) and non-tuberculous mycobacterial infections (NTMs) is well described, most notably . The exact pathophysiology is not known. We report a case of a 31-year-old male with concomitantly diagnosed HCL and disseminated infection who presented with rash, pancytopenia, and bulky axillary lymphadenopathy. The was initially diagnosed through use of cell-free DNA detection and confirmed by bone marrow and lymph node cultures. Hairy Cell Leukemia was diagnosed with peripheral flow cytometry and confirmed via the same bone marrow sample. His HCL was put into remission with a single course of cladribine and rituximab chemotherapy; however, his infection persisted for 6 months despite aggressive antimicrobial and surgical therapy. It was finally controlled using high-dose rifampin in combination with azithromycin and ethambutol. This case highlights the known link between HCL and Furthermore, it hints at potential causes beyond chemotherapy-induced immunocompromise. Notable possibilities include HCL cells acting as sanctuary sites for to evade the immune system, and subclinical infections causing NLRP3 inflammasome overactivation to trigger the oncogenic transformation to HCL. More research into the pathophysiologic link between HCL and infections would allow for more effective prevention, diagnosis, and treatment of these severe atypical infections which are the major cause of morbidity in the cladribine era of HCL treatment.
Topics: Humans; Male; Leukemia, Hairy Cell; Adult; Mycobacterium Infections, Nontuberculous; Mycobacterium kansasii; Cladribine; Rifampin; Azithromycin; Rituximab
PubMed: 38767131
DOI: 10.1177/23247096241253343 -
International Journal of Nanomedicine 2024The committed differentiation fate regulation has been a difficult problem in the fields of stem cell research, evidence showed that nanomaterials could promote the...
PURPOSE
The committed differentiation fate regulation has been a difficult problem in the fields of stem cell research, evidence showed that nanomaterials could promote the differentiation of stem cells into specific cell types. Layered double hydroxide (LDH) nanoparticles possess the regulation function of stem cell fate, while the underlying mechanism needs to be investigated. In this study, the process of embryonic stem cells (ESCs) differentiate to neural progenitor cells (NPCs) by magnesium aluminum LDH (MgAl-LDH) was investigated.
METHODS
MgAl-LDH with diameters of 30, 50, and 100 nm were synthesized and characterized, and their effects on the cytotoxicity and differentiation of NPCs were detected in vitro. Dot blot and MeRIP-qPCR were performed to detect the level of mA RNA methylation in nanoparticles-treated cells.
RESULTS
Our work displayed that LDH nanoparticles of three different sizes were biocompatible with NPCs, and the addition of MgAl-LDH could significantly promote the process of ESCs differentiate to NPCs. 100 nm LDH has a stronger effect on promoting NPCs differentiation compared to 30 nm and 50 nm LDH. In addition, dot blot results indicated that the enhanced NPCs differentiation by MgAl-LDH was closely related to mA RNA methylation process, and the major modification enzyme in LDH controlled NPCs differentiation may be the mA RNA methyltransferase METTL3. The upregulated METTL3 by LDH increased the mA level of mRNA, enhancing its stability.
CONCLUSION
This work reveals that MgAl-LDH nanoparticles can regulate the differentiation of ESCs into NPCs by increasing mA RNA methylation modification of .
Topics: Cell Differentiation; Animals; Neural Stem Cells; Mice; Nanoparticles; Methylation; Hydroxides; Methyltransferases; Particle Size; Embryonic Stem Cells; Adenosine; Aluminum Hydroxide; Magnesium Hydroxide
PubMed: 38766656
DOI: 10.2147/IJN.S463141 -
Scientific Reports May 2024Identifying and controlling tumor escape mechanisms is crucial for improving cancer treatment effectiveness. Experimental studies reveal tumor hypoxia and adenosine as...
Identifying and controlling tumor escape mechanisms is crucial for improving cancer treatment effectiveness. Experimental studies reveal tumor hypoxia and adenosine as significant contributors to such mechanisms. Hypoxia exacerbates adenosine levels in the tumor microenvironment. Combining inhibition of these factors with dendritic cell (DC)-based immunotherapy promises improved clinical outcomes. However, challenges include understanding dynamics, optimal vaccine dosages, and timing. Mathematical models, including agent-based, diffusion, and ordinary differential equations, address these challenges. Here, we employ these models for the first time to elucidate how hypoxia and adenosine facilitate tumor escape in DC-based immunotherapy. After parameter estimation using experimental data, we optimize vaccination protocols to minimize tumor growth. Sensitivity analysis highlights adenosine's significant impact on immunotherapy efficacy. Its suppressive role impedes treatment success, but inhibiting adenosine could enhance therapy, as suggested by the model. Our findings shed light on hypoxia and adenosine-mediated tumor escape mechanisms, informing future treatment strategies. Additionally, identifiability analysis confirms accurate parameter determination using experimental data.
Topics: Adenosine; Dendritic Cells; Humans; Immunotherapy; Tumor Escape; Tumor Microenvironment; Animals; Models, Theoretical; Neoplasms; Tumor Hypoxia; Mice; Hypoxia
PubMed: 38762567
DOI: 10.1038/s41598-024-62209-6 -
Oncology Reports Jun 2024Prostate cancer (PCa) affects males of all racial and ethnic groups, and leads to higher rates of mortality in those belonging to a lower socioeconomic status due to the... (Review)
Review
Prostate cancer (PCa) affects males of all racial and ethnic groups, and leads to higher rates of mortality in those belonging to a lower socioeconomic status due to the late detection of the disease. PCa affects middle‑aged males between the ages of 45 and 60 years, and is the highest cause of cancer‑associated mortality in Western countries. As the most abundant and common mRNA modification in higher eukaryotes, N‑methyladenosine (mA) is widely distributed in mammalian cells and influences various aspects of mRNA metabolism. Recent studies have found that abnormal expression levels of various mA regulators significantly affect the development and progression of various types of cancer, including PCa. The present review discusses the influence of mA regulatory factors on the pathogenesis and progression of PCa through mRNA modification based on the current state of research on mA methylation modification in PCa. It is considered that the treatment of PCa with micro‑molecular drugs that target the epigenetics of the mA regulator to correct abnormal mA modifications is a direction for future research into current diagnostic and therapeutic approaches for PCa.
Topics: Humans; Male; Prostatic Neoplasms; Adenosine; Gene Expression Regulation, Neoplastic; Epigenesis, Genetic; RNA, Messenger; Methyltransferases
PubMed: 38757383
DOI: 10.3892/or.2024.8747