Exogenous IGF-1 improves tau pathology and neuronal pyroptosis in high-fat diet mice with cognitive dysfunction.

Insulin-like growth factor-1 (IGF-1) improves obesity-induced cognitive dysfunction, but its mechanism is not fully clarified. The aim of the study was to reveal whether IGF-1 treated cognitive dysfunction by improving tau pathology and neuronal pyroptosis in high-fat diet mice. During in vitro experiment, C57BL/6J mice were fed with high-fat diet, and were treated with PEG-IGF-1, IGF-1 receptor blocker AXL1717, HO-1 blocker Znpp IX or their combinations. Cognitive function was evaluated using Morris water maze. Expression of Nrf2, HO-1, p-tau, NLRP3, caspase-1 and IL-1ß in hippocampus was determined using western blotting. Pyroptosis rate in hippocampus was measured using flow cytometry. During in vivo experiment, HN-h cells were treated with palmitic acid, pyroptosis blocker nonecrosulfonamide or their combinations. The expression of the proteins and rate of pyroptosis were also measured using western blotting and flow cytometry. During in vitro experiment, high-fat diet mice showed cognitive dysfunction, significant hyperphosphorylation of tau protein and neuronal pyroptosis in hippocampus compared with the sham mice. After exogenous IGF-1 treatment, these abnormalities were reversed and Nrf2/HO-1 signaling pathway was activated. Inhibition of the signaling pathway using AXL1717 or Znpp IX re-deteriorated cognitive function, tau pathology and neuronal pyroptosis in hippocampus. During in vivo experiment, inhibition of pyroptosis using nonecrosulfonamide improved tau pathology in palmitic acid-treated HN-h cells. Exogenous IGF-1 improved tau pathology induced by high-fat diet through inhibition of neuronal pyroptosis and activation of Nrf2/HO-1 signaling pathway.

KLF2 inhibits TGF-ß-mediated cancer cell motility in hepatocellular carcinoma.

Feedback regulation plays a pivotal role in determining the intensity and duration of TGF-ß signaling and subsequently affecting the pathophysiological roles of TGF-ß, including those in liver malignancy. KLF2, a member of the Krüppel-like factor (KLF) family transcription factors, has been implicated in impeding hepatocellular carcinoma (HCC) development. However, the underlying molecular mechanisms are not fully understood. In the present study, we found that TGF-ß stimulates the expression of KLF2 gene in several HCC cell lines. KLF2 protein is able to inhibit TGF-ß/Smad signaling in HCC cells as assessed by luciferase reporter assay. Further studies indicated that KLF2 inhibits the transcriptional activity of Smad2/3 and Smad4 and ameliorates TGF-ß-induced target gene expression, therefore creating a novel negative feedback loop in TGF-ß signaling. Functionally, stably expression of KLF2 in HCCLM3 cells attenuated TGF-ß-induced cancer cell motility in wound-healing and transwell assays by interfering with TGF-ß-mediated upregulation of MMP2. Together, our results revealed that KLF2 protein has a tumor-suppressive function in HCC through a negative feedback loop over TGF-ß signaling.

CXXC5: A novel regulator and coordinator of TGF-ß, BMP and Wnt signaling.

CXXC5 is a member of the CXXC-type zinc-finger protein family. Proteins in this family play a pivotal role in epigenetic regulation by binding to unmethylated CpG islands in gene promoters through their characteristic CXXC domain. CXXC5 is a short protein (322 amino acids in length) that does not have any catalytic domain, but is able to bind to DNA and act as a transcription factor and epigenetic factor through protein-protein interactions. Intriguingly, increasing evidence indicates that expression of the CXXC5 gene is controlled by multiple signaling pathways and a variety of transcription factors, positioning CXXC5 as an important signal integrator. In addition, CXXC5 is capable of regulating various signal transduction processes, including the TGF-ß, Wnt and ATM-p53 pathways, thereby acting as a novel and crucial signaling coordinator. CXXC5 plays an important role in embryonic development and adult tissue homeostasis by regulating cell proliferation, differentiation and apoptosis. In keeping with these functions, aberrant expression or altered activity of CXXC5 has been shown to be involved in several human diseases including tumourigenesis. This review summarizes the current understanding of CXXC5 as a transcription factor and signaling regulator and coordinator.

Feedback regulation of TGF-ß signaling.

Transforming growth factor beta (TGF-ß) is a multi-functional polypeptide that plays a critical role in regulating a broad range of cellular functions and physiological processes. Signaling is initiated when TGF-ß ligands bind to two types of cell membrane receptors with intrinsic Ser/Thr kinase activity and transmitted by the intracellular Smad proteins, which act as transcription factors to regulate gene expression in the nucleus. Although it is relatively simple and straight-forward, this TGF-ß/Smad pathway is regulated by various feedback loops at different levels, including the ligand, the receptor, Smads and transcription, and is thus fine-tuned in terms of signaling robustness, duration, specificity, and plasticity. The precise control gives rise to versatile and context-dependent pathophysiological functions. In this review, we firstly give an overview of TGF-ß signaling, and then discuss how each step of TGF-ß signaling is finely controlled by distinct modes of feedback mechanisms, involving both protein regulators and miRNAs.

Inhibitory Effects of Enterolactone on Growth and Metastasis in Human Breast Cancer.

A lignan-rich diet is associated with a lower risk of human breast cancer. Enterolactone, an active polyphenol metabolites of lignan, was reported to have an antitumor effect. We investigated the mechanism for the effect of enterolactone against human breast cancer. Cellular changes, and associated genes induced by enterolactone, were investigated in MDA-MB-231 cells. Enterolactone showed an antiproliferative effect, and its IC50 was 261.9 ± 10.5 µM for a treatment period of 48 hr. The mRNA levels of the genes related to cell proliferation, Ki67, PCNA, and FoxM1, were reduced. Enterolactone induced accumulation of cells in the S phase, and a lower expression of Cyclin E1, Cyclin A2, Cyclin B1, and Cyclin B2 genes. There were almost no changes in the transcription levels of the genes that participate in G0/G1 phase regulation, CDK4, CDK6, and Cyclin D1. Furthermore, enterolactone interfered with the cytoskeleton by downregulating phosphorylation of the FAK/paxillin pathway, inhibiting migration and invasion of cells. The results suggest that enterolactone exerts an antitumor effect by regulating the expression of genes associated with cell proliferation and the cell cycle and by blocking the FAK/paxillin signaling pathway. These findings provide new insights into the molecular mechanisms behind the antitumor effect of enterolactone.

Heat shock protein 90ß stabilizes focal adhesion kinase and enhances cell migration and invasion in breast cancer cells.

Focal adhesion kinase (FAK) acts as a regulator of cellular signaling and may promote cell spreading, motility, invasion and survival in malignancy. Elevated expression and activity of FAK frequently correlate with tumor cell metastasis and poor prognosis in breast cancer. However, the mechanisms by which the turnover of FAK is regulated remain elusive. Here we report that heat shock protein 90ß (HSP90ß) interacts with FAK and the middle domain (amino acids 233-620) of HSP90ß is mainly responsible for this interaction. Furthermore, we found that HSP90ß regulates FAK stability since HSP90ß inhibitor 17-AAG triggers FAK ubiquitylation and subsequent proteasome-dependent degradation. Moreover, disrupted FAK-HSP90ß interaction induced by 17-AAG contributes to attenuation of tumor cell growth, migration, and invasion. Together, our results reveal how HSP90ß regulates FAK stability and identifies a potential therapeutic strategy to breast cancer.

An overview of the co-transcription factor NACC1: Beyond its pro-tumor effects.

Nucleus accumbens-associated protein 1 (NACC1) is a member of the broad complex, tramtrack, bric-a-brac/poxvirus and zinc finger (BTB/POZ) protein families, mainly exerting its biological functions as a transcription co-regulator. NACC1 forms homo- or hetero-dimers through the BTB/POZ or BANP, E5R, and NACC1 (BEN) domain with other transcriptional regulators to regulate downstream signals. Recently, the overexpression of NACC1 has been observed in various tumors and is positively associated with tumor progression, high recurrence rate, indicating poor prognosis. NACC1 also regulates biological processes such as embryonic development, stem cell pluripotency, innate immunity, and related diseases. Our review combines recent research to summarize advancements in the structure, biological functions, and relative molecular mechanisms of NACC1. The future development of NACC1 clinical appliances is also discussed.

CXCL3: A key player in tumor microenvironment and inflammatory diseases.

CXCL3 (C-X-C Motif Chemokine 3), a member of the C-X-C chemokine subfamily, operates as a potent chemoattractant for neutrophils, thereby orchestrating the recruitment and migration of leukocytes alongside eliciting an inflammatory response. Recent inquiries have shed light on the pivotal roles of CXCL3 in the context of carcinogenesis. In the tumor microenvironment, CXCL3 emanating from both tumor and stromal cells intricately modulates cellular behaviors through autocrine and paracrine actions, primarily via interaction with its receptor CXCR2. Activation of signaling cascades such as ERK/MAPK, AKT, and JAK2/STAT3 underscores CXCL3's propensity to favor tumorigenic processes. However, CXCL3 exhibits dualistic behaviors, as evidenced by its capacity to exert anti-tumor effects under specific conditions. Additionally, the involvement of CXCL3 extends to inflammatory disorders like eclampsia, obesity, and asthma. This review encapsulates the structural attributes, biological functionalities, and molecular underpinnings of CXCL3 across both tumorigenesis and inflammatory diseases.

Development of an integrated and project-based laboratory course in upper-level biochemistry and molecular biology.

An integrated and projected-based laboratory course was described, integrating interconnected knowledge points and biochemistry and molecular biology techniques on a research project-based system. The program, which served as an essential extension of theoretical courses to practice, was conducted with a sophomore of basic medical science who had completed the course in medical biochemistry and molecular biology. This course engaged students in learning "genetic manipulation" and "recombinant DNA technology" to understand the target gene's role in disease mechanics, thus altering evaluation and treatment for clinical disease. Students could master applied and advanced techniques, such as cell culture, transfection, inducing exogenous fusion protein expression, purifying protein and its concentration assay, quantitative polymerase chain reaction, and western bot analysis. This laboratory exercise links laboratory practices with the methods of current basic research. Students need to complete the experimental design report and laboratory report, which could be advantageous for improving their ability to write lab summaries and scientific papers in the future. The reliability and validity analyses were conducted on the questionnaire, and we examined students' satisfaction with the course and their gains from the course. The student feedback was generally positive, indicating that the exercise helped consolidate theoretical knowledge, increase scientific research enthusiasm, and provide a powerful tool to be a better person and make informed decisions.

Exosomes derived from microglia overexpressing miR-124-3p alleviate neuronal endoplasmic reticulum stress damage after repetitive mild traumatic brain injury.

JOURNAL/nrgr/04.03/01300535-202409000-00033/figure1/v/2024-01-16T170235Z/r/image-tiff We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury. However, its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear. In this study, we first used an HT22 scratch injury model to mimic traumatic brain injury, then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p. We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress. Furthermore, luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α, while an IRE1α functional salvage experiment confirmed that miR-124-3p targeted IRE1α and reduced its expression, thereby inhibiting endoplasmic reticulum stress in injured neurons. Finally, we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced. These findings suggest that, after repetitive mild traumatic brain injury, miR-124-3 can be transferred from microglia-derived exosomes to injured neurons, where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress. Therefore, microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.

PAICS as a potential target for cancer therapy linking purine biosynthesis to cancer progression.

Tumor cells are required to undergo metabolic reprogramming for rapid development and progression, and one of the metabolic characteristics of cancer cells is the excessive synthesis and utilization of nucleotides. Abnormally increased nucleotides and their metabolites not only directly accelerate tumor cell progression but also indirectly act on stromal cells in the tumor microenvironment (TME) via a paracrine manner to regulate tumor progression. Purine nucleotides are mainly produced via de novo nucleotide synthesis in tumor cells; therefore, intervening in their synthesis has emerged as a promising strategy in anti-tumor therapy. De novo purine synthesis is a 10-step reaction catalyzed by six enzymes to synthesize inosine 5-monophosphate (IMP) and subsequently synthesize AMP and GMP. Phosphoribosylaminoimidazole carboxylase/phosphori-bosylaminoimidazole succinocarboxamide synthetase (PAICS) is a bifunctional enzyme that catalyzes de novo purine synthesis. Aberrantly elevated PAICS expression in various tumors is associated with poor prognosis. Evidence suggests that PAICS and its catalytic product, N-succinylcarboxamide-5-aminoimidazole ribonucleotide (SAICAR), could inhibit tumor cell apoptosis and promote the growth, epithelial-mesenchymal transition (EMT), invasion, and metastasis by regulating signaling pathways such as pyruvate kinase M2 (PKM2), extracellular signal-related kinases 1 and 2 (ERK1/2), focal adhesion kinase (FAK) and so on. This review summarizes the structure, biological functions and the molecular mechanisms of PAICS in cancer development and discusses its potential to be a target for tumor therapy.

Microglial exosomes alleviate intermittent hypoxia-induced cognitive deficits by suppressing NLRP3 inflammasome.

Intermittent hypoxia is the best predictor of developing cognitive decline and Alzheimer's disease progression in patients with obstructive sleep apnea. The nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasome has been poorly studied as a regulator of neuroinflammation in cognitive impairment caused by intermittent hypoxia. As critical inflammatory cells, exosomes secreted by microglia have been found to affect the spread of pathologic proteins and neuropathology in neurodegenerative diseases. However, the effects of microglial exosomes on neuroinflammation and cognitive outcomes after intermittent hypoxia remain unclear. In this study, the role of miRNAs in microglial exosomes in improving cognitive deficits in mice exposed to intermittent hypoxia was investigated. We demonstrated that miR-146a-5p fluctuated over time in microglial exosomes of mice exposed to intermittent hypoxia for different periods of time, which could regulate neuronal NLRP3 inflammasome and neuroinflammation. In primary neurons, we found that miR-146a-5p regulated mitochondrial reactive oxygen species by targeting HIF1α, thus affecting the NLRP3 inflammasome and secretion of inflammatory factors. Similarly, further studies showed that inhibition of NLRP3 by administering overexpressed miR-146a-5p in microglial exosomes and MCC950 has improved neuroinflammation and cognitive dysfunction in mice after intermittent hypoxia. In conclusion, NLRP3 inflammasome may be a regulatory target for ameliorating cognitive impairment caused by intermittent hypoxia, and microglial exosomal miR-146a-5p may be a promising therapeutic strategy.

CSF2 upregulates CXCL3 expression in adipocytes to promote metastasis of breast cancer via the FAK signaling pathway.

Recent studies have demonstrated that cancer-associated adipocytes (CAAs) in the tumor microenvironment are involved in the malignant progression of breast cancer. However, the underlying mechanism of CAA formation and its effects on the development of breast cancer are still unknown. Here, we show that CSF2 is highly expressed in both CAAs and breast cancer cells. CSF2 promotes inflammatory phenotypic changes of adipocytes through the Stat3 signaling pathway, leading to the secretion of multiple cytokines and proteases, particularly C-X-C motif chemokine ligand 3 (CXCL3). Adipocyte-derived CXCL3 binds to its specific receptor CXCR2 on breast cancer cells and activates the FAK pathway, enhancing the mesenchymal phenotype, migration, and invasion of breast cancer cells. In addition, a combination treatment targeting CSF2 and CXCR2 shows a synergistic inhibitory effect on adipocyte-induced lung metastasis of mouse 4T1 cells in vivo. These findings elucidate a novel mechanism of breast cancer metastasis and provide a potential therapeutic strategy for breast cancer metastasis.

Intranasal Delivery of Gene-Edited Microglial Exosomes Improves Neurological Outcomes after Intracerebral Hemorrhage by Regulating Neuroinflammation.

Neural inflammatory response is a crucial pathological change in intracerebral hemorrhage (ICH) which accelerates the formation of perihematomal edema and aggravates neural cell death. Although surgical and drug treatments for ICH have advanced rapidly in recent years, therapeutic strategies that target and control neuroinflammation are still limited. Exosomes are important carriers for information transfer among cells. They have also been regarded as a promising therapeutic tool in translational medicine, with low immunogenicity, high penetration through the blood-brain barrier, and ease of modification. In our previous research, we have found that exogenous administration of miRNA-124-overexpressed microglial exosomes (Exo-124) are effective in improving post-injury cognitive impairment. From this, we evaluated the potential therapeutic effects of miRNA-124-enriched microglial exosomes on the ICH mice in the present study. We found that the gene-edited exosomes could attenuate neuro-deficits and brain edema, improve blood-brain barrier integrity, and reduce neural cell death. Moreover, the protective effect of Exo-124 was abolished in mice depleted of Gr-1+ myeloid cells. It suggested that the exosomes exerted their functions by limiting the infiltration of leukocyte into the brain, thus controlling neuroinflammation following the onset of ICH. In conclusion, our findings provided a promising therapeutic strategy for improving neuroinflammation in ICH. It also opens a new avenue for intranasal delivery of exosome therapy using miRNA-edited microglial exosomes.

Effect of NMB-regulated ERK1/2 and p65 signaling pathway on proliferation and apoptosis of cervical cancer.

Aberrant expression of Neuromedin B (NMB) is associated with the malignant progression of cancer, such as breast cancer, lung cancer and glioma. However, the role of NMB in cervical cancer remains unclear. The present study found that NMB and its receptor NMBR are aberrantly expressed in cervical cancer. NMB activates ERK1/2 and NF-κB signaling pathways, which promote the proliferation of cervical cancer cells and increase the expression of tumor necrosis factor α (TNF-α). The downregulation of NMBR by the specific inhibitor, PD168368, abrogates proliferation and promotes apoptosis of cervical cancer cells. In addition, the NMB/NMBR signaling axis mediates the promoting effect of cancer-associated adipocytes on cervical cancer progression. These findings demonstrate the potential role of NMB/NMBR-regulated ERK1/2 and p65 signaling pathway in cervical cancer progression, which provide new opportunities to diagnose and treat cervical cancer.

The Molecular Basis and Therapeutic Potential of Leukemia Inhibitory Factor in Cancer Cachexia.

Cachexia is a chronic metabolic syndrome that is characterized by sustained weight and muscle mass loss and anorexia. Cachexia can be secondary to a variety of diseases and affects the prognosis of patients significantly. The increase in inflammatory cytokines in plasma is deeply related to the occurrence of cachexia. As a member of the IL-6 cytokine family, leukemia inhibitory factor (LIF) exerts multiple biological functions. LIF is over-expressed in the cancer cells and stromal cells of various tumors, promoting the malignant development of tumors via the autocrine and paracrine systems. Intriguingly, increasing studies have confirmed that LIF contributes to the progression of cachexia, especially in patients with metastatic tumors. This review combines all of the evidence to summarize the mechanism of LIF-induced cachexia from the following four aspects: (i) LIF and cancer-associated cachexia, (ii) LIF and alterations of adipose tissue in cachexia, (iii) LIF and anorexia nervosa in cachexia, and (iv) LIF and muscle atrophy in cachexia. Considering the complex mechanisms in cachexia, we also focus on the interactions between LIF and other key cytokines in cachexia and existing therapeutics targeting LIF.

Research advances in the study of sleep disorders, circadian rhythm disturbances and Alzheimer's disease.

Although there are still no satisfactory answers to the question of why we need to sleep, a better understanding of its function will help to improve societal attitudes toward sleep. Sleep disorders are very common in neurodegenerative diseases and are a key factor in the quality of life of patients and their families. Alzheimer's disease (AD) is an insidious and irreversible neurodegenerative disease. Along with progressive cognitive impairment, sleep disorders and disturbances in circadian rhythms play a key role in the progression of AD. Sleep and circadian rhythm disturbances are more common in patients with AD than in the general population and can appear early in the course of the disease. Therefore, this review discusses the bidirectional relationships among circadian rhythm disturbances, sleep disorders, and AD. In addition, pharmacological and non-pharmacological treatment options for patients with AD and sleep disorders are outlined.

Inhibition of Exosome Release Alleviates Cognitive Impairment After Repetitive Mild Traumatic Brain Injury.

BACKGROUND: Repetitive mild traumatic brain injury (rmTBI) is closely associated with chronic traumatic encephalopathy (CTE). Neuroinflammation and neuropathological protein accumulation are key links to CTE progression. Exosomes play important roles in neuroinflammation and neuropathological protein accumulation and spread. Here, we explored the role of brain-derived exosomes (BDEs) in mice with rmTBI and how the inhibition of BDE release contributes to neuroprotection. METHODS: GW4869 was used to inhibit exosome release, and behavioural tests, PET/CT and western blotting were conducted to explore the impact of this inhibition from different perspectives. We further evaluated cytokine expression by Luminex and microglial activation by immunofluorescence in mice with rmTBI after exosome release inhibition. RESULTS: Inhibition of BDE release reversed cognitive impairment in mice with rmTBI, enhanced glucose uptake and decreased neuropathological protein expression. Inhibition of BDE release also changed cytokine production trends and enhanced microglial proliferation. CONCLUSION: In this study, we found that BDEs are key factor in cognitive impairment in mice with rmTBI and that microglia are the main target of BDEs. Thus, inhibition of exosome release may be a new strategy for improving CTE prognoses.

Cancer-associated adipocytes promote the invasion and metastasis in breast cancer through LIF/CXCLs positive feedback loop.

Cancer-associated adipocytes (CAAs), which are adipocytes transformed by cancer cells, are of great importance in promoting the progression of breast cancer. However, the underlying mechanisms involved in the crosstalk between cancer cells and adipocytes are still unknown. Here we report that CAAs and breast cancer cells communicate with each other by secreting the cytokines leukemia inhibitory factor (LIF) and C-X-C subfamily chemokines (CXCLs), respectively. LIF is a pro-inflammatory cytokine secreted by CAAs, which promotes migration and invasion of breast cancer cells via the Stat3 signaling pathway. The activation of Stat3 induced the secretion of glutamic acid-leucine-arginine (ELR) motif CXCLs (CXCL1, CXCL2, CXCL3 and CXCL8) in tumor cells. Interestingly, CXCLs in turn activated the ERK1/2/NF-κB/Stat3 signaling cascade to promote the expression of LIF in CAAs. In clinical breast cancer pathology samples, the up-regulation of LIF in paracancerous adipose tissue was positively correlated with the activation of Stat3 in breast cancer. Furthermore, we verified that adipocytes enhanced lung metastasis of breast cancer cells, and the combination of EC330 (targeting LIF) and SB225002 (targeting C-X-C motility chemokine receptor 2 (CXCR2)) significantly reduced lung metastasis of breast cancer cells in vivo. Our findings reveal that the interaction of adipocytes with breast cancer cells depends on a positive feedback loop between the cytokines LIF and CXCLs, which promotes breast cancer invasion and metastasis.

Modafinil Reduces Neuronal Pyroptosis and Cognitive Decline After Sleep Deprivation.

Sleep deprivation (SD) induces systemic inflammation that promotes neuronal pyroptosis. The purpose of this study was to investigate the effect of an antioxidant modafinil on neuronal pyroptosis and cognitive decline following SD. Using a mouse model of SD, we found that modafinil improved learning and memory, reduced proinflammatory factor (IL-1ß, TNF-α, and IL-6) production, and increased the expression of anti-inflammatory factors (IL-10). Modafinil treatment attenuated inflammasome activity and reduced neuronal pyroptosis involving the NLRP3/NLRP1/NLRC4-caspase-1-IL-1ß pathway. In addition, modafinil induced an upregulation of brain-derived neurotrophic factor (BDNF) and synaptic activity. These results suggest that modafinil reduces neuronal pyroptosis and cognitive decline following SD. These effects should be further investigated in future studies to benefit patients with sleep disorders.