Traditional chemotherapy and radiotherapy for glioma are challenging due to the hypoxia in tumor microenvironment and the inability of chemotherapeutic agents to enter into tumor cells. Phototherapy is a novel therapeutic approach against various tumors in recent years. When combined with chemotherapy, the antitumor efficacy of phototherapy is superior than each alone. However, the combination of chemotherapy and phototherapy is still hampered by the hypoxic tumor microenvironment which upregulates the expression of hypoxia-inducible factor 1 (HIF-1) and its downstream pathways, as well as the thermoresistance caused by the overexpression of heat shock proteins (HSPs). To solve this, the biocompatible albumin-based nanoparticles (NPs) are developed to co-deliver IR780 iodine (IR780) and paclitaxel (PTX) simultaneously at an optimized ratio (IR780-PTX NPs) for synergistic photochemotherapy. Moreover, acriflavine (ACF), a chemical inhibitor of HIF-1, is formulated into intratumorally formed hydrogels to reinforce synergistic photochemotherapy. The continuously released ACF from hydrogel not only relieves the impact of photodynamic therapy-exacerbated tumor hypoxia by suppressing HIF-1 activity, but also efficiently attenuates HSP70 upregulation. The collaboration between IR780-PTX NPs and ACF hydrogels leads to an extraordinary antitumor effect in vitro and in vivo. The reinforced synergistic photochemotherapy via a single molecule by overcoming HIF-1 activity and HSP overexpression provides an effective therapeutic example to treat tumors, especially in those undergone severe hypoxia and/or therapy-induced thermoresistance.

Intervertebral disc degeneration (IVDD) is the major pathological cause of low back pain and global disability. Its chronic and persistent inflammatory microenvironment, resembling a flowing flood to erode the ecosystems relentlessly, disrupts the intervertebral disc homeostasis. In the present study, we first verified that Notch signaling is negatively correlated with inflammation in IVDD samples. Meanwhile, we identified a natural flavonoid hesperetin (Hes) as a potential agonist of Notch1 by molecular docking predicting. Herein, we developed an EV-inspired bioactive reservoir system, in which the natural extracts hes was encapsulated into liposomes (Hes@lipo) and embedded within a gelatin methacryloyl (GM) hydrogel (GM/Hes@lipo)to achieve sustained release. By mimicking the extracellular matrix (ECM)-like microenvironment of the intervertebral disc (IVD), GM/Hes@lipo provided physiological environment for nucleus pulposus cells (NPCs) adhesion and growth maintenance. Furthermore, by activating Notch signaling, GM/Hes@lipo effectively restored the dynamic balance between pro- and anti-inflammatory cytokines and maintained ECM metabolic homeostasis, attenuating NOD-like receptor signaling, thereby inhibiting NPC pyroptosis. Based on these aspects, GM/Hes@lipo relieved the IVDD process, maintained annulus fibrosus integrity, and effectively alleviated discogenic pain after the platform was administrated into the intervertebral disc of the rats. Collectively, as an anti-inflammatory "floodcontrol" system, the Notch signaling-targeted biomimetic hydrogel presents a biomimetic-natural compound combinatorial strategy offering promising therapy for mitigating IVDD progression.

Alzheimer's disease (AD) presents a complex pathogenesis involving amyloid-β (Aβ) plaques, tau tangles, and neuroinflammation. Recent evidence highlights δ-opioid receptor (DOR) as a unique and promising therapeutic target for AD. This review summarizes current knowledge on DOR's multifaceted neuroprotective role in AD pathology. While its involvement in Aβ regulation appears context-dependent, DOR activation consistently attenuates tau hyperphosphorylation, modulates microglial dysfunction, suppresses harmful neuroinflammation and inhibits complement-mediated synaptic pruning. All these findings have been well documented in in vitro and in vivo AD animal models. Furthermore, preclinical findings from general depression and anxiety models indicate that selective DOR agonists could help alleviate neuropsychiatric symptoms like depression and agitation, which are commonly seen in AD. DOR-associated genetic markers have also shown AD diagnostic potential. We conclude that targeting DOR offers a novel and integrative strategy impacting key AD pathological hallmarks: Aβ, tau, and neuroinflammation, as well as managing cognitive and emotional symptoms. Future research should focus on elucidating precise molecular mechanisms and translating these findings into clinical applications for AD diagnosis and therapy.

Intervertebral disc degeneration (IVDD), characterized by oxidative stress, mitochondrial dysfunction and extracellular matrix (ECM) breakdown, is a major contributor to low back pain. Current regenerative strategies often fail to address both the biological and structural aspects of IVDD in an integrated manner. Here, we demonstrate that chondroitin sulfate (CS) exerts a dual therapeutic role by enhancing endogenous antioxidant defenses and promoting anabolic ECM synthesis in both annulus fibrosus cells (AFCs) and nucleus pulposus cells (NPCs). Mechanistically, CS activates the integrin α4β1-PI3K-Akt signaling pathway, preserving mitochondrial integrity and restoring redox homeostasis. Furthermore, we developed an injectable, multifunctional PVA/collagen (Col)/CS hydrogel that integrates mechanical support, bioactivity and targeted CS delivery to enable unified repair of the disc's biphasic structure. In a rat IVDD model, this hydrogel effectively preserved disc architecture, restored disc height and MRI signal and upregulated key matrix and antioxidant markers, demonstrating coordinated repair of both the annulus fibrosus (AF) and the nucleus pulposus (NP). Our study establishes CS as a potent dual-function agent and presents an integrated hydrogel-based strategy for functional disc regeneration.

Intervertebral disc degeneration (IVDD) is a globally prevalent disease, yet achieving dual repair of tissue and function presents significant challenges. Considering reactive oxygen species (ROS) is a primary cause of IVDD, and given the decrease of nucleus pulposus cells (NPCs) and extensive degradation of extracellular matrix (ECM) during IVDD development, the present study, inspired by the "seeds-and-soil" strategy, has developed NPCs-loaded TBA@Gel&Chs hydrogel microspheres. These microspheres serve as exogenous supplements of NPCs and ECM analogs, replenishing "seeds" and "soil" for nucleus pulposus repair, and incorporating polyphenol antioxidant components to interrupt the oxidative stress-IVDD cycle, thereby constructing a microsphere system where NPCs and ECM support each other. Experiments proved that TBA@Gel&Chs exhibited significant extracellular ROS-scavenging antioxidant capabilities while effectively upregulating intracellular antioxidant proteins expression (Sirt3 and Sod2). This dual-action antioxidant capability effectively protects the vitality and physiological functions of NPCs. The therapeutic effects of microspheres on IVDD were also confirmed in rat models, which was found significantly restore histological structure and mechanical properties of degenerated discs. Additionally, RNA-seq results have provided evidences of antioxidant mechanism by which TBA@Gel&Chs protected NPCs from oxidative stress. Therefore, the NPCs-loaded TBA@Gel&Chs microspheres developed in this study have achieved excellent therapeutic effects, offering a paradigm using antioxidant biomaterials combined with cellular therapy for IVDD treatment.

Postoperative acute kidney injury (AKI) and postoperative delirium (POD) are two of the most common complications after surgery. It is essential to understand their common mechanisms not only to prevent and predict the occurrence of these complications, but also to guide perioperative management and improve surgical outcomes. This review summarizes the recent literature focused on these postoperative complications and explores the relationship between AKI and POD. Numerous clinical studies have used AKI and POD as primary outcomes and have found that AKI and POD often occur simultaneously in the perioperative period in susceptible groups undergoing major surgery. Some research findings indicate that the brain and the kidney exhibit bidirectional communication that is affected by systemic inflammation, drug accumulation, uremic toxins, vascular endothelial injury, and fluid volume redistribution during the perioperative period. AKI and POD share common mechanisms involving a variety of complex physiological and pathological pathways, leading to impairment of renal and cerebral function.

While previous studies have well established δ-opioid receptor (DOR)-mediated neuroprotection against Alzheimer's pathology, the underlying mechanisms remain poorly understood. Our present work reveals a strong negative correlation between DOR and the classical complement pathway (CCP) initiator C1q, confirming their direct binding both in vitro and in APP/PS1 transgenic mice. Activating DOR with the specific agonist UFP-512 in aged APP/PS1 mice reduced cerebral C1q levels, while increasing DOR-C1q binding affinity. This interaction subsequently suppressed CCP activation, ameliorated complement-dependent synaptic engulfment by microglia, prevented synaptic protein loss, and consequently improved cognitive performance of these Alzheimer's disease (AD) mice. Consistent with these findings, overexpressing microglial DOR effectively inhibited its shift towards a phagocytotic phenotype and protected co-cultured neurons from lipopolysaccharide (LPS) -induced injury. Collectively, our findings demonstrate a critical role of DOR in restricting complement-mediated synaptic elimination during neurodegeneration, highlighting its potential as a new therapeutic target for AD.

Recent studies suggest that opioid receptor signaling may differentially affect Alzheimer’s disease (AD) pathology and the relevant behavioral dysfunctions. However, the precise roles and mechanisms of opioid receptor subtypes in AD pathologies are still unclear with major controversies. We compared the delta-opioid receptor (DOR)- and mu-opioid receptor (MOR)-mediated effects on AD-associated cognitive deficits, pathologies, neuroinflammations, cell death using transgenic APP/PS1 mouse model and BV2 cell line at behavioral, molecular, and cellular levels. Unpaired t-test and one/two way analysis for variance (ANOVA) were used to analyze statistical significance of the data. We show a distinct role of DOR and its major difference with MOR in AD injury in an APP/PS1 mouse model. DOR activation by UFP-512, but not MOR activation by DAMGO, attenuated cognitive impairment, reduced beta-amyloid (Aβ) production and aggregation, as well as protected the neurons from apoptosis in APP/PS1 mice. DOR and MOR also differentially modulated microglia in APP/PS1 mice and in vitro AD cell model with a DOR-mediated inhibition on the excessive activation of microglia and the release of pro-inflammatory cytokines in AD pathologies. Gene expression profiling further revealed that the alternations in DOR/MOR are closely associated with microglial homeostatic signatures and high mobility group protein B1 (HMGB1) in AD. DOR activation inhibited HMGB1 secretion and its translocation from nuclear to cytoplasm. Our in-vitro studies further confirmed that DOR overexpression mitigated microglial inflammatory response and rescued neurons from AD injury via HMGB1-NF-κB signaling pathway. These novel findings uncover previously unappreciated roles of DOR in neuroprotection against AD injury via modulating microglia-related inflammatory responses.

Intervertebral disc (IVD) degeneration represents a significant cause of chronic back pain and disability, with a substantial impact on the quality of life. Conventional therapeutic modalities frequently address the symptoms rather than the underlying etiology, underscoring the necessity for regenerative therapies that restore disc function. Polysaccharide-based materials, such as hyaluronic acid, alginate, chitosan, and chondroitin sulfate, have emerged as promising candidates for intervertebral disc degeneration (IVDD) therapy due to their biocompatibility, biodegradability, and ability to mimic the native extracellular matrix (ECM) of the nucleus pulposus (NP). These materials have demonstrated the capacity to support cell viability, facilitate matrix production, and alleviate inflammation in vitro and in vivo, thus supporting tissue regeneration and restoring disc function in comparison to conventional treatment. Furthermore, polysaccharide-based hydrogels have demonstrated the potential to deliver bioactive molecules, including growth factors, cytokines and anti-inflammatory drugs, directly to the degenerated disc environment, thereby enhancing therapeutic outcomes. Therefore, polysaccharide-based materials provide structural support and facilitate the regeneration of native tissue, representing a versatile and effective approach for the treatment of IVDD. Despite their promise, challenges such as limited long-term stability, potential immunogenicity, and the difficulty in scaling up production for clinical use remain. This review delineates the potential of various polysaccharides during the fabrication of hydrogels and scaffolds for disc regeneration, guiding and inspiring future research to focus on optimizing these materials for clinical translation for IVDD repair and regeneration.

Intervertebral disc degeneration (IDD) is an important cause of disability worldwide, where abnormal compressive loading plays a crucial role. Several microRNAs (miRNAs) have been reported to be involved in IDD. However, mechanically responsive miRNAs in IDD have not been fully investigated. Furthermore, the deficiency of an effective miRNA delivery system is a key prerequisite for achieving intradiscal therapy. In the present study, mechanically responsive miR-1249 is identified via miRNA-sequencing to be down-regulated in compression-induced IDD of rats. It is further revealed that miR-1249 exerts a protective effect on the metabolism of the extracellular matrix of the nucleus pulposus (NP) by targeting Nrarp. Based on the mechanism study, extracellular vesicle-mimetic nanovesicles are developed by extruding NP cells as a miRNA therapeutic system to integrate with miR-1249 mimics (NV-mimics). In vivo, the local injection of NV-mimics could effectively alleviate the progression of abnormal compressive stress-induced IDD, including the retention of the water content and height of the disks, the conservation of the NP tissues, and the improvement of imbalance metabolism of extracellular matrix, which is evidenced by imaging examination and histological analyses, respectively. The present study provides a promising therapeutic strategy for delaying the progression of IDD.

Hypoxia and reactive oxygen species (ROS) overaccumulation cause persistent oxidative stress and impair intrinsic regenerative potential upon tissue injury. For local tissue injury with hypoxia, such as bone fracture and defects, a localized-sufficient oxygen supply is highly desirable but remains challenging. Therefore, to explore a strategy and its intrinsic mechanism for supplying oxygen locally and remodeling the regenerative microenvironment, an innovative oxygenating hydrogel microsphere system with sustained oxygenation and antioxidant properties is introduced by loading CaO2@SiO2@PDA (CSP) nanoparticles. Specifically, the CSP nanoparticles exhibited broad-spectrum free radicals scavenging ability, along with prolonged controlled-release of oxygen once integrated into the gelatin methacrylate anhydride (GelMA) microspheres (CSP-GM). The CSP-GM with extra cellular matrix (ECM)-mimicking structures reconstructed living niches, promoting the adhesion and proliferation of bone marrow stromal cells (BMSCs). As a multifaceted microenvironment regulator, CSP-GM remodeled the regenerative microenvironment by synergistically producing oxygen and scavenging ROS, recovering mitochondrial homeostasis and antioxidant defenses of BMSCs, promoting angiogenesis and osteogenesis under hypoxia conditions via precisely modulating the Nrf2/HO-1 signaling pathway. The multiple pro-regenerative effects of the implantable functionalized micro-oxygen reservoir on bone repair are further corroborated by the enhanced vascularized bone formation in rat femoral defects, presenting a comprehensive and promising strategy for tissue repair.

Mesenchymal glioma stem cells (MES GSCs) are a subpopulation of cells in glioblastoma (GBM) that contribute to a worse prognosis owing to their highly aggressive nature and resistance to radiation therapy. Here, OCT4 is characterized as a critical factor in sustaining the stemness phenotype of MES GSC. We find that OCT4 is expressed intensively in MES GSC and is intimately associated with poor prognosis, moreover, OCT4 depletion leads to diminished invasive capacity and impairment of the stem phenotype in MES GSC. Subsequently, we demonstrated that USP5 is a deubiquitinating enzyme which directly interacts with OCT4 and preserves OCT4 stability through its deubiquitination. USP5 was additionally proven to be aberrantly over-expressed in MES GSCs, and its depletion resulted in a noticeable diminution of OCT4 and consequently a reduced self-renewal and tumorigenic capacity of MES GSCs, which can be substantially restored by ectopic expression of OCT4. In addition, we detected the dominant molecule that regulates USP5 transcription, E2F1, with dual luciferase reporter gene analysis. In combination, targeting the E2F1-USP5-OCT4 axis is a potentially emerging strategy for the therapy of GBM.

Neuroinflammation underlies the pathophysiology of multiple age-related neurological disorders. Microglia, the resident immune cells of the central nervous system, are critically involved in neuroinflammatory regulation and neural survival. Modulating microglial activation is thus a promising approach to alleviate neuronal injury. Our serial studies have revealed a neuroprotective role of the.-opioid receptor (DOR) in several acute and chronic cerebral injuries by regulating neuroinflammation and cellular oxidative stress. More recently, we found an endogenous mechanism for the inhibition of neuroinflammation is closely related to DOR's modulation of microglia. Our recent studies showed that DOR activation could strongly protect neurons from hypoxia- and lipopolysaccharide (LPS)-induced injury by inhibiting microglial pro-inflammatory transformation, while knocking-down DOR or restraining DOR activity promoted microglia activation and the relevant inflammatory events with an aggravation of cell injury. This novel finding highlights a therapeutic potential of DOR in numerous age-related neurological disorders through the modulation of neuroinflammation by targeting microglia. This review summarized the current data regarding the role of microglia in neuroinflammation, oxidative stress, and age-related neurological diseases focusing on the pharmacological effects and signaling transduction of DOR in microglia.

Neuroinflammation underlies the pathophysiology of multiple age-related neurological disorders. Microglia, the resident immune cells of the central nervous system, are critically involved in neuroinflammatory regulation and neural survival. Modulating microglial activation is thus a promising approach to alleviate neuronal injury. Our serial studies have revealed a neuroprotective role of the δ-opioid receptor (DOR) in several acute and chronic cerebral injuries by regulating neuroinflammation and cellular oxidative stress. More recently, we found an endogenous mechanism for the inhibition of neuroinflammation is closely related to DOR's modulation of microglia. Our recent studies showed that DOR activation could strongly protect neurons from hypoxia- and lipopolysaccharide (LPS)-induced injury by inhibiting microglial pro-inflammatory transformation, while knocking-down DOR or restraining DOR activity promoted microglia activation and the relevant inflammatory events with an aggravation of cell injury. This novel finding highlights a therapeutic potential of DOR in numerous age-related neurological disorders through the modulation of neuroinflammation by targeting microglia. This review summarized the current data regarding the role of microglia in neuroinflammation, oxidative stress, and age-related neurological diseases focusing on the pharmacological effects and signaling transduction of DOR in microglia.

The PI3K/AKT pathway plays an essential role in tumour development. NOD-like receptors (NLRs) regulate innate immunity and are implicated in cancer, but whether they are involved in PI3K/AKT pathway regulation is poorly understood. Here, we report that NLRP6 potentiates the PI3K/AKT pathway by binding and destabilizing p85α, the regulatory subunit of PI3K. Mechanistically, NLRP6 recruits the E3 ligase RBX1 to p85α and ubiquitinates lysine 256 on p85α, which is recognized by the autophagy cargo receptor OPTN, causing selective autophagic degradation of p85α and subsequent activation of the PI3K/AKT pathway by reducing PTEN stability. We further show that loss of NLRP6 suppresses cell proliferation, colony formation, cell migration, and tumour growth in glioblastoma cells in vitro and in vivo. Disruption of the NLRP6/p85α interaction using the Pep9 peptide inhibits the PI3K/AKT pathway and generates potent antitumour effects. Collectively, our results suggest that NLRP6 promotes p85α degradation via selective autophagy to drive tumorigenesis, and the interaction between NLRP6 and p85α can be a promising therapeutic target for tumour treatment.

Cell death and functional loss of nucleus pulposus cell play essential roles in intervertebral disc degeneration (IDD). Ferroptosis is a newly identified cell death type, and its role in IDD is still under investigation. Identifying the key genes of ferroptosis in IDD helps to identify the therapeutic targets of IDD. In this study, we downloaded the human IDD mRNA microarray data from the Gene Expression Omnibus and ferroptosis genes from FerrDb, then performed a series of analyses using strict bioinformatics algorithms. In general, we obtained 40 ferroptosis-related differential expression genes (FerrDEGs) and identified six ferroptosis key gene signatures, namely, ATF3, EIF2S1, AR, NQO1, TXNIP, and AKR1C3. In addition, enrichment analysis of the FerrDEGs was conducted, the protein-protein interaction network was constructed, the correlations between ferroptosis key genes and immune infiltrating cells were analyzed, and the lncRNA-miRNA-mRNA ceRNA network was constructed. In particular, ATF3 and EIF2S1 showed the strongest correlation with immune cell function, which might lead to the development of IDD. Finally, the expressions of ferroptosis key genes were verified in the rat compression-induced IDD. In conclusion, this preliminary study analyzed and verified the mechanism of ferroptosis in IDD, laid a foundation for the follow-up study of the mechanism of ferroptosis in IDD, and provided new targets for preventing and delaying IDD.

Microglia are involved in the regulation of cerebral homeostasis and pathogen confrontation. There is, however, evidence showing that excessive microglia activation is implicated in various age-related cerebral diseases. On the other hand, microglia may experience complex changes of polarization in pathological insults, i.e., from a proinflammatory M1 to an anti-inflammatory M2 phenotype, which differentially contribute to the exacerbation or alleviation of cellular injury. Remolding the phenotype of microglia or inhibiting the excessive activation of microglia seems to be a promising approach against neurodegenerative pathologies. Since δ-opioid receptor (DOR) activation exhibits a strong protective capacity against various neuronal injuries, especially the hypoxic/ischemic injury, we asked if the DOR-induced neuroprotection is associated with its effect on microglia. We explored this fundamental issue by using pharmacological and genetic approaches in the BV2 cell line, a general type of microglial cells. The results showed that DOR expression significantly increased in the activated microglial M2 phenotype, but slightly decreased in the microglial M1 phenotype. Hypoxia induced dual polarizations of BV2 cells with an increase in DOR expression. Administration of a specific DOR agonist, UFP-512, largely inhibited lipopolysaccharide (LPS) or hypoxia-induced microglial M1 activation and inflammatory activity with high concentrations of UFP-512 being effective to reverse the interleukin-4 (IL4)-induced microglial activation. Consistent with these observations, inhibiting DOR or knocking-down DOR promoted the excessive activation of BV2 cells in both M1 and M2 directions, while DOR overexpression did the opposite. Furthermore, the PC12 cells exposed to the conditioned medium of BV2 cells treated by UFP-512 grew better than those treated directly with UFP-512 under LPS or hypoxic insults. DOR inhibitor naltrindole could block all the effects of DOR activation. The medium from the BV2 cells with DOR knock-down decreased the viability of PC12 cell, while the medium from the BV2 cells with DOR overexpression largely attenuated LPS or hypoxic injury in the PC12 cells. These first data suggest a close linkage between DOR expression/function and microglial polarization and a critical role of DOR in negative controlling microglial activation. Our work provides a novel clue for new protective strategies against neurodegenerative pathophysiology through DOR-mediated regulation of microglia.

Objective:To evaluate the role of Nod-like receptor family pyrin domain-containing 3 (NLRP3) in the dorsal root ganglion (DRG) in persistent postoperative pain in rats.Methods:Forty-eight male Sprague-Dawley rats, in which IT catheters were successfully implanted, weighing 200-250 g, aged 2-3 months, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (S group), persistent postoperative pain group (P group), persistent postoperative pain+ NLRP3-siRNA group (P+ siRNA group) and persistent postoperative pain+ NLRP3-scrRNA group (P+ scrRNA group). A persistent postoperative pain model was established by skin/muscle incision and retraction (SMIR) in anesthetized animals.Normal saline 10 μl were intrathecally injected in S group and P group, NLRP3-siRNA 10 μl and NLRP3-scrRNA 10 μl were intrathecally injected in CP+ siRNA group and CP+ scrRNA group, respectively, at 3 days before operation.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation (T 0) and 1, 5, 10, 15 and 20 days after operation (T 1-5). Six rats in each group were randomly selected and sacrificed at T 3, and the L 4-5 DRGs on the operated side were harvested for determination of the expression of NLRP3 and caspase-1 (by Western blot), NLRP3 mRNA expression (by real-time polymerase chain reaction) and content of interleukin-1beta (IL-1β) (by enzyme-linked immunosorbent assay). Results:Compared with group S, the MWT was significantly decreased at T 2-5, the expression of NLRP3 protein and mRNA in DRGs was up-regulated, and the content of IL-1β was increased in group P ( P<0.05). Compared with group P, the MWT was significantly increased at T 2-5, the expression of NLRP3 protein and mRNA and caspase-1 was down-regulated, and the content IL-1β was decreased in group P+ siRNA ( P<0.05), and no significant change was found in the parameters mentioned above in group P+ scrRNA ( P>0.05). Conclusion:NLRP3 in DRGs is involved in the development of persistent postoperative pain, and the mechanism may be related to the development of NLPR3 inflammasomes which further induces peripheral neuroinflammatory response in rats.