MOLECULAR AND CELLULAR BIOCHEMISTRY

Mitochondrial dysfunction in pregnancy loss: a review
Lu L, Huang X, Shi Y, Jiang Y, Han Y and Zhang Y
A receptive endometrium, a healthy embryo, and harmonious communication between the mother and the embryo/fetus are necessary for a healthy and successful pregnancy. Pregnancy loss (PL) can be the outcome if there is a flaw in any of these critical developmental processes. Multiple risk factors contribute to PL, including genetic predispositions, uterine abnormalities, immune imbalances, endocrine dysfunctions, and environmental exposures, among others. Despite extensive investigations, more than half of women with recurrent pregnancy loss (RPL) lack identifiable risk factors, and causes of RPL remain elusive. To date, an accumulating body of evidence indicates that mitochondrial dysfunction in reproductive organs or cells is a potential underlying factor that may trigger PL. In this comprehensive review, we delve into the intricate relationship between mitochondrial dysfunction and PL, examining studies that focus on this connection in the context of diverse reproductive organs and cells, to unravel the interwoven links between these factors and gain a deeper understanding of their interconnectedness.
Correction to: Sacubitril/valsartan attenuated myocardial inflammation, fibrosis, apoptosis and promoted autophagy in doxorubicin-induced cardiotoxicity mice via regulating the AMPKα-mTORC1 signaling pathway
Hu F, Yan S, Lin L, Qiu X, Lin X and Wang W
PCSK9 and its relationship with HMGB1, TLR4, and TNFα in non-statin and statin-treated coronary artery disease patients
Desouky DA, Nosair NA, Salama MK, El-Magd MA, Desouky MA and Sherif DE
Despite statin use in coronary artery disease (CAD), significant risk remains, potentially due to increased proprotein convertase subtilisin/kexin-type 9 (PCSK9) production, which raises LDL-C levels and induces inflammation. The exact relationship between PCSK9, inflammatory markers like TNFα, TLR4, CRP, and HMGB1, and monocyte subsets is poorly understood. This study aimed to explore these relationships in non-statin and statin-taking CAD patients. This case-control study included 91 controls and 91 stable CAD patients, divided into no-statin (NS, n = 25), low-dose statin (LDS, n = 25), and high-dose statin (HDS, n = 41) groups. Serum levels of LDL-C, CRP, PCSK9, TLR4, HMGB1, and TNFα were measured. Monocyte subsets were classified using flow cytometry into classical monocytes (CM), intermediate monocytes (IM), and non-classical monocytes (NCM). CAD patients showed elevated PCSK9, LDL-C, and inflammatory markers compared to controls. Statin groups (LDS, HDS) had lower LDL-C and inflammatory markers but higher PCSK9 than the NS group, with the HDS group showing the lowest LDL-C and inflammatory markers but the highest PCSK9. In the NS group, PCSK9 positively correlated with inflammatory markers (HMGB1, TNFα, TLR4, CRP) and monocyte subsets (IM%, NCM%). In the total statin group (LDS + HDS), PCSK9 negatively correlated with HMGB1, TLR4, and NCM%, for each, respectively, and positively with CM%. Multivariable linear regression showed significant associations between PCSK9 and HMGB1, NCM%, and IM% in the NS group, and HMGB1, NCM%, and TLR4 in the total statin group. In conclusion, we recommend combining PCSK9 inhibitors with statins in high-risk CAD patients. This may enhance statin efficacy, reduce LDL-C, and inhibit the TLR4/NF-кB inflammatory pathway, decreasing atherosclerotic inflammation.
Correction to: Cytoglobin augments ferroptosis through autophagic degradation of ferritin in colorectal cancer cells
Fan C, Luo Z, Zheng Q, Xu Y, Xu Y, Chen J, Meng Y, Jiang H, Liu K and Xi Y
Catechin promotes endoplasmic reticulum stress-mediated gastric cancer cell apoptosis via NOX4-induced reactive oxygen species
Jiang J, Li D, Li F, Li H, Zhang X and Feng L
Catechin, a polyphenolic compound in various foods and beverages, shows strong anti-cancer effects against gastric cancer (GC) cells. This study explored the effect of catechin on GC cell apoptosis and endoplasmic reticulum (ER) stress. GC cells were treated with different catechin concentrations to assess effects on cell viability, LDH release, invasion, migration, apoptosis, intracellular calcium (Ca⁺), ER stress markers, and reactive oxygen species (ROS). siRNA knockdown targeted GRP78, PERK, CHOP, and NOX4 to examine their roles in catechin-induced ER stress and apoptosis. Catechin treatment significantly reduced GC cell viability, increased LDH release, and induced apoptosis dose-dependently. Catechins elevated intracellular Ca⁺ and ER stress markers. Co-treatment with thapsigargin (TG) intensified these effects, implicating ER stress in apoptosis. Knocking down GRP78, PERK, and CHOP mitigated catechin-induced apoptosis and restored viability. Additionally, catechins raised ROS levels, while co-treatment with Diphenyleneiodonium (DPI) or N-acetylcysteine (NAC) lowered ROS, cell damage, and ER stress markers. NOX4 knockdown countered catechin-induced viability loss and upregulated CHOP and cleaved caspase-3. Catechin induces apoptosis in GC cells through ER stress and ROS generation. Key mediators include GRP78, PERK, CHOP, and NOX4, suggesting potential therapeutic targets for enhancing catechin efficacy in GC treatment.
Human umbilical cord mesenchymal stem cells improve bone marrow hematopoiesis through regulation of bone marrow adipose tissue
Feng J, Zhang M, Ren H, Ren Y, Hao Z, Bian S, Cui J, Li S, Xu J, Daniel MM, Ren F, Xu Z, Tan Y, Chen X, Zhang Y, Chang J and Wang H
Bone marrow adipose tissue (BMAT) exhibits a multitude of biological functionalities and influences hematopoiesis. The adiposity status of the bone marrow may play a role in the decline of hematopoietic function. Mesenchymal stem cells (MSCs) constitute crucial regulators within the bone marrow microenvironment; however, their precise role in modulating BMAT and the subsequent implications for hematopoiesis remain poorly understood. We conducted in vivo studies to observe the effects of human umbilical cord mesenchymal stem cells (hucMSCs) on BMAT accumulation and restoration of hematopoietic function in mice with drug-induced hematopoietic impairment. Concurrently, in vitro co-culture experiments were used to investigate the impact of hucMSCs on preadipocytes and mature adipocytes, and the potential subsequent consequences for hematopoietic cells. Moreover, we explored the potential mechanisms underlying these interactions. Our findings reveal that hucMSCs concomitantly mitigate BMAT accumulation and facilitate the recovery of hematopoietic function in mouse models with drug-induced hematopoietic impairment. In vitro, hucMSCs potentially impede adipogenic differentiation of 3T3-L1 preadipocytes through interference with the JAK2/STAT3 signaling pathway and affect the functionality of mature adipocytes, thus mitigating the detrimental effects of adipocytes on hematopoietic stem cells (HSCs). Furthermore, we demonstrate that hucMSCs may protect hematopoietic cells from adipocyte-induced damage by protecting antioxidative mechanisms. These results suggest that hucMSCs exhibit an inhibitory effect on the excessive expansion of adipose tissue and modulate adipose tissue function, which may potentially contribute to the regulation of the bone marrow microenvironment and favorably influence hematopoietic function improvement.
Cytoglobin augments ferroptosis through autophagic degradation of ferritin in colorectal cancer cells
Fan C, Luo Z, Zheng Q, Xu Y, Xu Y, Chen J, Meng Y, Jiang H, Liu K and Xi Y
Autophagy has gained importance in the context of ferroptosis. Nevertheless, a deeper understanding of the regulatory mechanism governing autophagy-dependent ferroptosis is necessary. Cytoglobin (CYGB), a member of the globin family, exhibits antifibrotic effects, regulates cellular reactive oxygen species, and stimulates tumor inhibition. Herein, we present further insights into the role of CYGB in ferroptosis regulation. Our investigation confirmed that CYGB impedes cell proliferation and migration. Furthermore, a significant association between CYGB and the lysosomal pathway was suggested based on the RNA sequencing data analysis. Elevated lysosomal signal and colocalization of CYGB with lysosome-associated membrane glycoprotein 1 (LAMP1) were observed. Moreover, upregulated autophagy and augmented ferroptosis induced by RSL3 were confirmed in CYGB-overexpression cells with an obviously increased colocalization of nuclear receptor coactivator 4 (NCOA4) and LC3B. The autophagy inhibitor bafilomycin or chloroquine alleviated autophagy-dependent degradation of ferritin protein under RSL3 treated condition. Additionally, a colocalization of CYGB with the transferrin receptor (TFR) was confirmed. Our results demonstrate an important functional pathway by which CYGB regulates ferroptosis through TFR-binding and autophagic degradation of ferritin, and provide a potential pathway for the treatment of colorectal cancer.
Extracellular vesicles derived from bone marrow mesenchymal stem cells ameliorate liver fibrosis via micro-7045-5p
Liu Z, Jiang X, You H, Tang Z, Ma Y, Che N, Liu W and Ma C
Liver fibrosis is a crucial pathological factor in the persistence and progression of chronic liver disease. Increasing evidence has demonstrated the significant potential of extracellular vesicles (EVs) secreted by bone marrow mesenchymal stem cells (BMSCs) in the clinical treatment of liver fibrosis. This study aimed to mechanistically investigate the impact of BMSC-derived EVs (BMSC-EVs) containing miR-7045-5p on the autophagy of activated hepatic stellate cells (HSCs) during liver fibrosis.
Research advances in branched-chain amino acid metabolism in tumors
Li Z, Chen S, Wu X, Liu F, Zhu J, Chen J, Lu X and Chi R
The metabolic reprogramming of amino acids is an important component of tumor metabolism. Branched-chain amino acids (BCAAs) perform important functions in tumor progression. They are the important amino donor and are involved in the synthesis of various non-essential amino acids, nucleotides, and polyamines to satisfy the increased demand for nitrogen sources. This review summarizes the studies related to abnormalities in BCAA metabolism during tumorigenesis and the potential therapeutic targets. The expression of BCAA transporters was significantly upregulated in tumor cells, which increases BCAA uptake. High expression of the BCAA transaminases is prevalent in various tumors, however, the dehydrogenation step of BCAA catabolism is inhibited in tumors. This review shows that BCAA metabolic reprogramming is an important tumor metabolic feature, and metabolic genes of BCAAs play a crucial role in tumor metabolism, representing a good auxiliary target for early clinical diagnosis and treatment. In addition, BCAAs are indispensable for maintaining immune system function, and dietary supplementation with BCAAs can enhance the activity of immune cells. Therefore, BCAA supplementation in tumor patients may affect the interaction between the immune system and tumors.
Unleashing the therapeutic power of verteporfin-eluting stents: modulating YAP signaling to combat carotid artery restenosis and cerebral watershed infarction
Zhang P, Xu C, Liu Z, Geng Y and Liu H
Carotid artery stenosis is the main cause of cerebral watershed infarction (CWI). In recent years, increasing attention has been given to treating this condition. The present study aimed to investigate how Verteporfin-eluting stent (VPES) modulates the YAP signaling pathway to inhibit restenosis of the carotid artery and alleviate CWI. Through transcriptome sequencing and functional experiments, it was found that VP could regulate the Yes-associated protein (YAP) signaling pathway and effectively suppress the proliferation and migration of smooth muscle cells (SMCs). Further investigation revealed that VPES could inhibit carotid artery restenosis through the YAP signaling pathway in a rabbit model, reducing the occurrence of CWI.
Oxaliplatin and 5-fluorouracil promote epithelial-mesenchymal transition via activation of KRAS/ERK/NF-κB pathway in KRAS-mutated colon cancer cells
Hoshida T, Tsubaki M, Takeda T, Asano R, Choi IH, Takimoto K, Inukai A, Imano M, Tanabe K, Nagai N and Nishida S
Oxaliplatin (L-OHP) and 5-fluorouracil (5-FU) are used to treat colon cancer; however, resistance contributes to poor prognosis. Epithelial-mesenchymal transition (EMT) has been induced in tumor tissues after administration of anticancer drugs and may be involved in drug resistance. We investigated the mechanism of EMT induction in colon cancer cells treated with 5-FU and L-OHP. We found that L-OHP and 5-FU at clinical steady-state concentrations induced EMT in LoVo and DLD-1 cells (KRAS G13D-mutated), but not in HT-29 and Caco-2 cells (KRAS wild type). L-OHP and 5-FU elevated vimentin, N-cadherin, Twist, Slug, and Snail and decreased E-cadherin expressions. Moreover, 5-FU- and L-OHP -induced EMT cells showed increased cell migration and decreased sensitivity to 5-FU and L-OHP. L-OHP and 5-FU treatment promoted KRAS, ERK1/2, and NF-κB activation. Combined administration with KRAS siRNA, MEK1/2 inhibitor trametinib, and NF-κB inhibitor dimethyl fumarate (DMF), suppressed L-OHP- and 5-FU-induced EMT. These results suggest that KRAS/ERK/NF-κB pathway activation is important for EMT induction by L-OHP and 5-FU treatment. Thus, MEK1/2 and NF-κB inhibitors may facilitate the resistance acquisition to L-OHP and 5-FU therapy in KRAS G13D-mutated colon cancer.
KMT2A facilitates the epithelial-to-mesenchymal transition and the progression of ovarian cancer
Zhu Y, Jiang S, Tang R, Chen H, Jia G, Zhou X and Miao J
Epithelial-mesenchymal transition (EMT) plays critical roles in cancer progression and metastasis. Thus, the exploration of the molecular mechanism regulating EMT would provide potential opportunities for the therapy of metastatic ovarian cancer (OC). Herein, we investigated the putative role of KMT2A in modulating EMT and metastasis in OC. The expression of KMT2A in OC was detected by Western blot and immunohistochemistry and its relationship with clinicopathological factors was analyzed. The effect of KMT2A on the biological behavior of OC cells was examined. Moreover, the expressions of EMT-associated proteins were detected in vivo and vitro by Western blot, immunofluorescence, and immunohistochemistry. KMT2A was highly expressed in OC cell lines and tissues and was positively correlated with advanced International Federation of Gynecology and Obstetrics (FIGO) stage, pathological grade, and metastasis. KMT2A overexpression was correlated with poor prognosis. Suppression of KMT2A inhibited OC cells proliferation, migration, and invasion and induced their apoptosis in vitro and vivo. In contrast, the ectopic expression of KMT2A had the opposite effects. Furthermore, KMT2A knockdown inhibited TGF-β-induced EMT in OC and reduced the phosphorylation levels of Smad2. Taken together, these observations demonstrate that KMT2A could promote the malignant behavior of OC by activating TGF-β/Smad signaling pathway and may be a potential prognostic biomarker and therapeutic target for OC.
The role of immunoglobins in atherosclerosis development; friends or foe?
Zhang L, Li P, Li Y, Qu W, Shi Y, Zhang T and Chen Y
Coronary artery disease, atherosclerosis, and its life-threatening sequels impose the hugest burden on the healthcare systems throughout the world. The intricate process of atherosclerosis is considered as an inflammatory-based disorder, and therefore, the components of the immune system are involved in different stages from formation of coronary plaques to its development. One of the major effectors in this way are the antibody producing entities, the B cells. These cells, which play a significant and unique role in responding to different stress, injuries, and infections, contribute differently to the development of atherosclerosis, either inhibitory or promoting, depending on the type of subsets. B cells implicate in both systemic and local immune responses of an atherosclerotic artery by cell-cell contact, cytokine production, and antigen presentation. In particular, natural antibodies bind to oxidized lipoproteins and cellular debris, which are abundant during plaque growth. Logically, any defects in B cells and consequent impairment in antibody production may greatly affect the shaping of the plaque and its clinical outcome. In this comprehensive review, we scrutinize the role of B cells and different classes of antibodies in atherosclerosis progression besides current novel B-cell-based therapeutic approaches that aim to resolve this affliction of mankind.
M2 macrophage-derived exosomes promote cell proliferation, migration and EMT of non-small cell lung cancer by secreting miR-155-5p
Fang H, Chi X, Wang M, Liu J, Sun M, Zhang J and Zhang W
Tumor-associated macrophages (TAMs) are a type of highly plastic immune cells in the tumor microenvironment (TME), which can be classified into two main phenotypes: classical activated M1 macrophages and alternatively activated M2 macrophages. As previously reported, M2-polarized TAMs play critical role in promoting the progression of non-small cell lung cancer (NSCLC) via secreting exosomes, but the detailed mechanisms are still largely unknown. In the present study, the THP-1 monocytes were sequentially induced into M0 and M2-polarized macrophages, and the exosomes were obtained from M0 (M0-exos) and M2 (M2-exos) polarized macrophages, respectively, and co-cultured with NSCLC cells (H1299 and A549) to establish the exosomes-cell co-culture system in vitro. As it was determined by MTT assay, RT-qPCR and Transwell assay, in contrast with the M0-exos, M2-exos significantly promoted cell proliferation, migration and epithelial-mesenchymal transition (EMT) process in NSCLC cells. Next, through screening the contents in the exosomes, it was verified that miR-155-5p was especially enriched in the M2-exos, and M2-exos enhanced cancer aggressiveness and tumorigenesis in in vitro NSCLC cells and in vivo xenograft tumor-bearing mice models via delivering miR-155-5p. The detailed molecular mechanisms were subsequently elucidated, and it was found that miR-155-5p bound with HuR to increase the stability and expression levels of VEGFR2, which further activated the tumor-promoting PI3K/Akt/mTOR signal pathway, and M2-exos-enhanced cancer progression in NSCLC cells were apparently suppressed by downregulating VEGFR2 and PI3K inhibitor LY294002 co-treatment. Taken together, M2-polarized TAMs secreted miR-155-5p-containing exosomes to enhanced cancer aggressiveness of NSCLC by activating the VEGFR2/PI3K/Akt/mTOR pathway in a HuR-dependent manner.
RBM15-mediated the m6A modification of MAT2A promotes osteosarcoma cell proliferation, metastasis and suppresses ferroptosis
Huang Z, Chen P and Liu Y
Methionine adenosyltransferase 2 A (MAT2A) has been found to mediate osteosarcoma (OS) progression. Therefore, more roles and mechanisms of MAT2A in the development of OS deserve further exploration. The mRNA and protein levels of MAT2A and RNA binding motif protein 15 (RBM15) were tested by quantitative real-time PCR and western blot (WB). Cell proliferation and metastasis were examined using EdU assay and transwell assay. The protein levels of metastasis-related markers and ferroptosis-related marker were measured by WB. Cell ferroptosis was assessed via testing GSH, ROS, and Fe levels. Mice xenograft model was constructed to explore the roles of MAT2A and RBM15 in vivo. RBM15 and MAT2A interaction was assessed by MeRIP assay and dual-luciferase reporter assay. High expression of MAT2A was observed in OS tumor tissues and cells. MAT2A knockdown reduced OS cell proliferation, migration, invasion and enhanced ferroptosis. Silencing of MAT2A inhibited OS tumor growth in vivo. RBM15 was upregulated in OS tumor tissues and cells, which could promote MAT2A expression by N6-methyladenosine (m6A) modification. Downregulation of RBM15 repressed OS cell behaviors and tumorigenesis by decreasing MAT2A expression. In conclusion, MAT2A, regulated by RBM15-mediated m6A modification, accelerated OS malignant progression by increasing cell proliferation, metastasis and decreasing ferroptosis.
Toll-like receptors polymorphisms and COVID-19: a systematic review
Dos Santos BRC, Dos Santos LKC, Ferreira JM, Dos Santos ACM, Sortica VA and de Souza Figueiredo EVM
COVID-19 is a disease caused by SARS-CoV-2. It became a health problem affecting the lives of millions of people. Toll-like receptors are responsible for recognizing viral particles and activating the innate immune system. The genetic factors associated with COVID-19 remain unclear. Thus, this study aims to assess the association between the polymorphism in Toll-like receptors and susceptibility to COVID-19. We searched the electronic databases (Science Direct, PUBMED, Web of Science, and Scopus) for studies assessing the association between Toll-like receptor polymorphisms and susceptibility to COVID-19. The quality of the studies was assessed using the Q-Genie tool. Thirteen studies were included in this systematic review. The studies analyzed polymorphisms in TLR2, TLR3, TLR4, TLR7, TLR8 and TLR9. We used SNP2TFBS bioinformatic analysis to identify the variants influencing transcription factor binding sites. The Ensembl Genome Browser was used to assess the allele and genotype frequencies in different populations. The bioinformatic analysis revealed that the variant rs5743836 of TLR9 affects the transcription factor binding sites NFKB1 and RELA. The genotype frequency of the variants rs3775291, rs3853839, rs3764880 were higher in East Asian population compared to the other populations. The frequency of the rs3775290 variant was higher in East and South Asian populations. The rs179008 variant was higher in the European population, and the rs5743836 was higher in the African population. Toll-like receptors play an important role in COVID-19 susceptibility. Further studies in different populations are necessary to elucidate the role of Toll-like receptors polymorphisms in SARS-CoV-2 infection.
The role of the farnesoid X receptor in diabetes and its complications
Zhang S, Zhang D, Xu K, Huang X, Chen Q and Chen M
Diabetes is a metabolic disease in which tissues and organs are exposed to a hyperglycemic environment for a prolonged period. Long-term hyperglycemia can cause dysfunction of multiple organs and tissues in the body, leading to diabetic complications such as diabetic cardiomyopathy and diabetic nephropathy. Diabetes and its complications have become one of the key issues that seriously threaten the health of people worldwide. Farnesoid X receptor (FXR), as a metabolic regulator, has multiple functions in regulating insulin synthesis and secretion, insulin resistance, lipid metabolism, oxidative stress, inflammatory response, and fibrosis. It plays a key role in alleviating diabetes and its complications. In this review, we discuss the latest findings of FXR related to diabetes and its complications, focusing on its role in diabetes, diabetic nephropathy, diabetic cardiomyopathy, and diabetic liver injury. The aim is to better understand the role of FXR in diabetes and its complications and to provide new perspectives on the treatment of diabetes and its complications.
Alteration of methylation pattern and gene expression of FTO, PPARγ and Slc2a4 on pre-diabetes-induced BALB/c mice
Listiyani P, Sanjaya R, Nathanael J, Chandra PS, Artadana IBM and Dwi Putra SE
T2DM is a serious global health problem and usually caused by unhealthy diet, such diet with high carbohydrate or monosodium glutamate (MSG). In this study, we used the T2DM mice (BALB/c) model by exposing the mice with foods high in carbohydrate (HCD) or MSG (HMD) to determine the changes in molecular expression and methylation pattern of genes correlated to the development of T2DM. The data including clinical data, i.e. body weight, fasting blood glucose, and glucose tolerance, as well as gene expression, methylation pattern of glucose transport related gene (Slc2a4, FTO, and PPARγ) and also collagen deposition were measured. HCD and HMD diet for 18 weeks failed to show any clinical development of T2DM. However, it was shown that both diets significantly altered the methylation pattern and gene expression. A decrease in the expression level of Slc2a4 accompanied with a decreased methylation level in its NF-κB attachment site was observed in both groups. In addition, both treatments also showed a decrease in the expression of PPARγ in contrast to its elevated methylation level. On the other hand, a significant increase in the expression of FTO was apparent. Furthermore, an increase in collagen deposition in both groups was also detected. Overall, this study showed that an alteration on the expression and methylation pattern of the genes that are associated with glucose transportation was observed in HCD and HMD despite having no T2DM clinical development. It can potentially be a new biomarker for detection of pre-diabetes.
The tumor suppressor SALL2 opposes chemotherapeutic resistance in breast cancer
Li Q, Li C, Zhang Y, Zheng Z, Wang Y, Yang Y, Zhu Q, Wang R, Xu W, Zhu C, Tian Q, Wang M and Ye L
Chemotherapy continues to be the primary treatment for certain types of breast cancer. However, despite an initial positive response to chemotherapeutic agents, the development of resistance is inevitable. The exact molecular mechanisms underlying this phenomenon remain unclear. In this research, a significant downregulation of SALL2 expression was observed in chemo-resistant breast cancer, which was attributed to promoter methylation. Decreased SALL2 expression correlated significantly with poorer relapse-free survival in chemotherapy-treated patients with breast cancer. Functionally, SALL2 silencing induced a stem cell-like phenotype in breast cancer cells, fostering resistance to cisplatin both in vitro and in vivo. This resistance was mediated, at least in part, through the transcriptional regulation of BTG2, a negative regulator of stemness, achieved by direct binding to its promoter regions. These findings underscore the critical role of SALL2 in modulating cisplatin response and propose SALL2 as a potential prognostic biomarker for chemotherapy response in breast cancer.
Novel hypothesis and therapeutic interventions for irritable bowel syndrome: interplay between metal dyshomeostasis, gastrointestinal dysfunction, and neuropsychiatric symptoms
Nakagawa Y and Yamada S
Irritable bowel syndrome is a gastrointestinal disorder due to multiple pathologies. While patients with this condition experience anxiety and depressed mood more frequently than healthy individuals, it is unclear how gastrointestinal dysfunction interacts with such neuropsychiatric symptoms. Data suggest that irritable bowel syndrome patients predominantly display a lower zinc intake, which presumably impairs enterochromaffin cells producing 5-hydroxytryptamine, gut bacteria fermenting short-chain fatty acids, and barrier system in the intestine, with the accompanying constipation, diarrhea, low-grade mucosal inflammation, and visceral pain. Dyshomeostasis of copper and zinc concentrations as well as elevated pro-inflammatory cytokine levels in the blood can disrupt blood-cerebrospinal fluid barrier function, leading to locus coeruleus neuroinflammation and hyperactivation with resultant amygdalar overactivation and dorsolateral prefrontal cortex hypoactivation as found in neuropsychiatric disorders. The dysregulation between the dorsolateral prefrontal cortex and amygdala is likely responsible for visceral pain-related anxiety, depressed mood caused by anticipatory anxiety, and visceral pain catastrophizing due to catastrophic thinking or cognitive distortion. Collectively, these events can result in a spiral of gastrointestinal symptoms and neuropsychiatric signs, prompting the progression of irritable bowel syndrome. Given that the negative feedback mechanism in regulation of the hypothalamic-pituitary-adrenal axis is preserved in a subset of neuropsychiatric cases, dorsolateral prefrontal cortex abnormality accompanied by neuropsychiatric symptoms may be a more significant contributing factor in brain-gut axis malfunction than activation of the hypothalamic corticotropin-releasing hormone system. The proposed mechanistic model could predict novel therapeutic interventions for comorbid irritable bowel syndrome and neuropsychiatric disorders.
The neuroinflammatory role of microRNAs in Alzheimer's disease: pathological insights to therapeutic potential
Liu W, Rao X, Sun W, Chen X, Yu L, Zhang J, Chen J and Zheng X
Alzheimer's disease (AD) is a neurodegenerative disease and the most common cause of dementia, contributing to around 60-80% of cases. The main pathophysiology of AD is characterized by an abnormal accumulation of protein aggregates extracellularly (beta-amyloid plaques) and intracellularly (neurofibrillary tangles of hyperphosphorylated tau). However, an increasing number of studies have also suggested neuroinflammation may have a crucial role in precipitating the cascade reactions that result in the development of AD neuropathology. In particular, several studies indicate microRNAs (miRNAs) can act as regulatory factors for neuroinflammation in AD, with potential to affect the occurrence and/or progression of AD inflammation by targeting the expression of multiple genes. Therefore, miRNAs may have potential as therapeutic targets for AD, which requires more research. This article will review the existing studies on miRNAs that have been identified to regulate neuroinflammation, aiming to gain further insights into the specific regulatory processes of miRNAs, highlight the diagnostic and therapeutic potential of miRNAs as biomarkers in AD, as well as current challenges, and suggest the further work to bridge the gap in knowledge to utilize miRNAs as therapeutic targets for AD.