Nitric Oxide Scavenging and Hydrogen Sulfide Production Synergistically Treat Rheumatoid Arthritis

Semisynthesis and biological evaluation of 17-hydroxybrevianamide N derivatives as anti-inflammatory agents by mediating NF-κB and MAPK signaling pathways

Chronic inflammation is a trigger for many diseases that affect approximately 10-20 % of the population around the world. Herein, (±)-17-hydroxybrevianamide N (1) was isolated from the fungus Aspergillus sp. (CHNSCLM-0151) and exhibited strong inhibitory activity against nitric oxide (NO) in lipopolysaccharide (LPS)-induced RAW264.7 cell. A series of new derivatives (±)-3-(±)-29 was semisynthesized by structural modification of the imide, phenolic hydroxyl, and carbonyl groups from the natural product (±)-1. The results of anti-inflammatory activity demonstrated that (±)-4, (±)-6, (±)-9, (±)-22, (±)-23, and (±)-24 exhibited obviously NO inhibitory (P < 0.0001) in LPS-stimulated RAW264.7 cells. To further investigate the relationship between chirality and activity, the enantiomers of the above six compounds were obtained by chiral resolution. As expected, the bioactivity results indicated stereoselectivity in the anti-inflammatory effect among the different isomers. In particular, compound (+)-4S-23 inhibited NO concentration with an IC50 value of 0.5 μM, demonstrating 3-fold greater potency compared to its (R)-enantiomer, and achieving 40-fold superior potency over the positive control NG-monomethyl-l-arginine (L-NMMA). This compound demonstrated suppression of TNF-α (25.7 ± 1.5 %), IL-6 (54.5 ± 3.9 %) and IL-1β (92.9 ± 4.1 %) production at 2 μM. More importantly, mechanistic investigations revealed that (+)-4S-23 (0.2 μM) modulates the MAPK signaling pathway, specifically downregulating phosphorylation of p38, ERK, and JNK. Furthermore, (+)-4S-23 also exhibited potent inhibitory activity against the NF-κB pathway by suppressing the phosphorylation of IκB-α and blocking nuclear translocation of phosphorylated p65. Notably, these findings position (+)-4S-23 as a promising candidate for development as a novel anti-inflammatory therapeutic targeting both MAPK and NF-κB signaling nodes.

Monitoring the level of hydrogen sulfide in arthritis and its treatment with a novel near-infrared fluorescent probe

Hydrogen sulfide (H2S) is a physiological gaseous transmitter that plays a crucial role in maintaining the cellular redox state. Arthritis is usually accompanied by redness, swelling, pain, dysfunction and deformity of the joints, and in severe cases can lead to joint disability. Disorders of H2S level are associated with the pathological process of arthritis. In this paper, a near-infrared fluorescent probe (TX-H2S) was developed to detect the alterations in H2S levels of arthritis. TX-H2S has excellent response performance to H2S such as near-infrared emission (725 nm), large Stokes shift (125 nm) and high fluorescence enhancement (72-fold). Owing to low cytotoxicity, the probe can be employed to observe the alterations of exogenous and endogenous H2S level in HeLa and HepG2 cells. By making full use of near-infrared emission and good biocompatibility, the probe can be employed for exogenous H2S imaging in mice, and is able to track the fluctuation of H2S level during arthritis and its treatment. These make the probe have the potential to invent an efficient tool for the diagnosis of arthritic disease and its treatment.

Erythrocyte membrane camouflaged celastrol and bilirubin self-assembly for rheumatoid arthritis immunotherapy based on STING inhibition and RONS clearance

Activation of cGAS-STING signaling pathway and accumulation of reactive oxygen and nitrogen species (RONS) are important issues facing the treatment of rheumatoid arthritis (RA). Here, we report a biomimetic nano-Chinese medicine (HA-RM-Cel-BR) for RA immunotherapy based on STING inhibition of celastrol (Cel) and RONS clearance of bilirubin (BR). HA-RM-Cel-BR is constructed by the carrier-free self-assembly of active ingredients Cel and BR from traditional Chinese medicine, and then camouflaged by hyaluronic acid (HA)-modified red blood cell membranes (RM). HA-RM-Cel-BR prolongs circulation time through RM camouflage, targets inflamed joints by HA modification, and remodels the joint immune microenvironment by STING inhibition and RONS clearance. More importantly, HA-RM-Cel-BR shows excellent therapeutic effects on RA rat model, and significantly reduces hepatotoxicity associated with Cel. Our work provides a new strategy for RA immunotherapy with traditional Chinese medicine ingredients.

S-propargyl-cysteine attenuates temporomandibular joint osteoarthritis by regulating macrophage polarization via Inhibition of JAK/STAT signaling

BACKGROUND

Temporomandibular joint osteoarthritis (TMJ-OA) is a disease characterized by cartilage degradation and synovial inflammation, with limited effective treatment currently. Synovial macrophage polarization is pivotal in TMJ-OA progression, making it a promising therapeutic aspect. This study investigated the effects of S-propargyl-cysteine (SPRC), an endogenous H2S donor, on macrophage polarization and its therapeutic potential in alleviating TMJ-OA.

METHODS

A MIA-induced TMJ-OA rat model and LPS-stimulated RAW264.7 macrophages were employed to evaluate the effects of SPRC in vivo and in vitro. TMJ bone and cartilage were analyzed via micro-CT and histological methods, while macrophage polarization markers expression were assessed via RT-qPCR, western blot, and immunofluorescence. RNA sequencing was performed on macrophages, and the JAK2/STAT3 signaling pathway was validated using the JAK2-specific inhibitor AG490. The direct effects of SPRC on rat primary condylar chondrocytes were examined by evaluating ECM synthesis and degradation. Co-culture experiments further assessed macrophage-chondrocyte interactions.

RESULTS

SPRC significantly alleviated cartilage and bone damage in the TMJ-OA rat model, as demonstrated by improved bone volume and cartilage structure. SPRC reduced pro-inflammatory M1 macrophage infiltration and enhanced anti-inflammatory M2 macrophage polarization. SPRC effectively inhibited the JAK2/STAT3, leading to reduction of inflammatory markers, including TNF-α, IL-6, and iNOS. Co-culture experiments revealed that SPRC-treated macrophage-conditioned medium improved chondrocyte metabolic activity and restored ECM integrity.

CONCLUSIONS

SPRC-modulated macrophage polarization alleviates TMJ-OA via JAK/STAT downregulation, thereby reducing synovial inflammation and cartilage degradation. These findings position SPRC as a promising therapeutic candidate for TMJ-OA and provide insights into novel strategies targeting macrophage polarization and synovium-cartilage crosstalk.

Photoacoustic Imaging in Inflammatory Orthopedic Diseases: Progress toward Precise Diagnostics and Predictive Regulation

With the intensification of aging issues, inflammatory orthopedic diseases almost occur in the majority of elderly people, which is becoming increasingly severe. Photoacoustic imaging (PAI) is a non-invasive visualization technique for a clear diagnosis of the inflammation areas through detecting acoustic signals generated by the laser irradiation. The combination of "light input" and "acoustic output" provides unprecedented scalability as well as high penetration depth and resolution. This new imaging technology can also present more anatomical information and feedback status of inflammatory activity for the orthopedic diseases. Especially in inflammation imaging, this technology can effectively supplement current clinical imaging methods in diagnosis, staging, and monitoring of pathophysiological processes. With the rapid development of these new technologies, the goals of precise diagnosis, predictive regulation, and ultimately personalized treatment strategies are becoming increasingly realistic. Herein, this article introduces various orthopedic inflammations and related imaging technology applications. It covers the types of PA nanoprobes and their research progress in orthopedic inflammation, as well as the potential applications of PAI in various aspects. The review also discusses the recent researches and emerging translational applications of PAI in orthopedic inflammation, as well as the prospects and future development challenges of clinical transformation.

NaHS@Cy5@MS@SP nanoparticles improve rheumatoid arthritis by inactivating the Hedgehog signaling pathway through sustained and targeted release of H2S into the synovium

BACKGROUND

Aberrant proliferation and inflammation of fibroblast-like synoviocytes (FLSs) significantly contribute to the pathogenesis of rheumatoid arthritis (RA). Deficiency of hydrogen sulfide (H2S) is a driving force for the development of RA, and the short half-life of the H2S-releasing donor sodium hydrosulfide (NaHS) limits its clinical application in RA therapy. Designing a targeted delivery system with slow-release properties for FLSs could offer novel strategies for treating RA.

METHODS

Herein, we designed a strategy to achieve slow release of H2S targeted to the synovium, which was accomplished by synthesizing NaHS-CY5@mesoporous silic@LNP targeted peptide Dil (NaHS@Cy5@MS@SP) nanoparticles.

RESULTS

Our results demonstrated that NaHS@Cy5@MS@SP effectively targets FLSs, upregulates H2S and its-producing enzyme cystathionine-γ-lyase (CSE) in the joints of arthritic mice. Overexpression of CSE inhibited the proliferation, migration, and inflammation of FLSs upon lipopolysaccharide (LPS) exposure, effects that were mimicked by NaHS@Cy5@MS@SP. In vivo studies showed that NaHS@Cy5@MS@SP achieved a threefold higher AUCinf than that of free NaHS, significantly improving the bioavailability of NaHS. Further, NaHS@Cy5@MS@SP inhibited synovial hyperplasia and reduced bone and cartilage erosion in the DBA/1J mouse model of collagen-induced arthritis (CIA), which was superior to NaHS. RNA sequencing and molecular studies validated that NaHS@Cy5@MS@SP inactivated the Hedgehog signaling pathway in FLSs, as evidenced by reductions in the protein expression of SHH, SMO, GLI1 and phosphorylated p38/MAPK.

CONCLUSION

This study highlights NaHS@Cy5@MS@SP as a promising strategy for the controlled and targeted delivery of H2S to synoviocytes, offering potential for RA management.

Contribution of macrophage polarization in bone metabolism: A literature review

Macrophage polarization divides macrophages into two main cell subpopulations, classically and alternatively activated macrophages (M1 and M2, respectively). M1 polarization promotes osteoclastogenesis, while M2 polarization promotes osteogenesis. The physiological homeostasis of bone metabolism involves a high dynamic balance between osteoclastic-mediated bone resorption and formation. Reportedly, M1/M2 imbalance causes the onset and persistence of inflammation-related bone diseases. Therefore, understanding the research advances in functions and roles of macrophages in such diseases will provide substantial guidance for improved treatment of bone diseases. In this review, we underscore and summarize the research advances in macrophage polarization, and bone-related diseases, such as rheumatoid arthritis, osteoarthritis, and osteoporosis, over the last 5 years. Our findings showed that targeting macrophages and balancing macrophage polarization can effectively reduce inflammation and decrease bone destruction while promoting bone formation and vascular repair. These results indicate that regulating macrophage and macrophage polarization to restore homeostasis is a prospective approach for curing bone-related diseases.

The Latest Applications of Carbon-Nitride-Based Materials for Combination Treatment of Cancer

Carbon-nitride-based (CN-based) materials have shown great potential in combination therapy in recent years. Due to their outstanding biocompatibility, ease of modification, and adjustable band-gap position, CN-based materials can be applied as photosensitizers in photodynamic therapy (PDT) and light-driven water-splitting catalysts in gas therapy. After doping with other elements, the photocatalytic performance of CN-based materials will be enhanced, and more interesting functions will be obtained. In addition, the large specific surface area also promotes CN-based materials as drug carriers combined with other therapeutic modalities to achieve combination therapy. This Review analyzes and summarizes the latest research on CN-based materials in combined therapies, such as PDT with photothermal therapy (PTT), PDT with sonodynamic therapy (SDT), PDT with drug therapy, PDT with gene therapy, gas therapy with PDT, and bioimaging-guided combined therapy. In particular, the applications of CN-based materials in gas and gene combination therapy are summarized for the first time. Finally, the current challenges faced by CN-based materials in combination therapy are further discussed.

Synergistic rheumatoid arthritis therapy by interrupting the detrimental feedback loop to orchestrate hypoxia M1 macrophage polarization using an enzyme-catalyzed nanoplatform

A detrimental feedback loop between hypoxia and oxidative stress consistently drives macrophage polarization toward a pro-inflammatory M1 phenotype, thus persistently aggravating rheumatoid arthritis (RA) progression. Herein, an enzyme-catalyzed nanoplatform with synergistic hypoxia-relieving and reactive oxygen species (ROS)-scavenging properties was developed using bovine serum albumin-bilirubin-platinum nanoparticles (BSA-BR-Pt NPs). Bilirubin was employed to eliminate ROS, while platinum exhibited a synergistic effect in scavenging ROS and simultaneously generated oxygen. In mice RA model, BSA-BR-Pt NPs treatment exhibited superior effects, resulting in significant improvements in joint inflammation, cartilage damage, and bone erosion, compared to methotrexate, the most widely used antirheumatic drug. Mechanistically, RNA-sequencing data and experimental results elucidated that BSA-BR-Pt NPs induced a re-polarization of hypoxic M1 macrophages to M2 macrophages via switching glycolysis to oxidative phosphorylation through the inhibition of HIF-1α pathway. Collectively, this research for the first time elaborated the underlying mechanism of enzyme-catalyzed nanoplatform in orchestrating macrophage polarization, and identified a novel therapeutic strategy for RA and other inflammatory disorders.

Nanomaterial-Based Repurposing of Macrophage Metabolism and Its Applications

Macrophage immunotherapy represents an emerging therapeutic approach aimed at modulating the immune response to alleviate disease symptoms. Nanomaterials (NMs) have been engineered to monitor macrophage metabolism, enabling the evaluation of disease progression and the replication of intricate physiological signal patterns. They achieve this either directly or by delivering regulatory signals, thereby mapping phenotype to effector functions through metabolic repurposing to customize macrophage fate for therapy. However, a comprehensive summary regarding NM-mediated macrophage visualization and coordinated metabolic rewiring to maintain phenotypic equilibrium is currently lacking. This review aims to address this gap by outlining recent advancements in NM-based metabolic immunotherapy. We initially explore the relationship between metabolism, polarization, and disease, before delving into recent NM innovations that visualize macrophage activity to elucidate disease onset and fine-tune its fate through metabolic remodeling for macrophage-centered immunotherapy. Finally, we discuss the prospects and challenges of NM-mediated metabolic immunotherapy, aiming to accelerate clinical translation. We anticipate that this review will serve as a valuable reference for researchers seeking to leverage novel metabolic intervention-matched immunomodulators in macrophages or other fields of immune engineering.

Dissecting hair breakage in alopecia areata: the central role of dysregulated cysteine homeostasis

In the initial stages of Alopecia Areata (AA), the predominance of hair breakage or exclamation mark hairs serves as vital indicators of disease activity. These signs are non-invasive and are commonly employed in dermatoscopic examinations. Despite their clinical salience, the underlying etiology precipitating this hair breakage remains largely uncharted territory. Our exhaustive review of the existing literature points to a pivotal role for cysteine-a key amino acid central to hair growth-in these mechanisms. This review will probe and deliberate upon the implications of aberrant cysteine metabolism in the pathogenesis of AA. It will examine the potential intersections of cysteine metabolism with autophagy, ferroptosis, immunity, and psychiatric manifestations associated with AA. Such exploration could illuminate new facets of the disease's pathophysiology, potentially paving the way for innovative therapeutic strategies.

Large-scale genome-wide association studies reveal the genetic causal etiology between air pollutants and autoimmune diseases

BACKGROUND

Epidemiological evidence links a close correlation between long-term exposure to air pollutants and autoimmune diseases, while the causality remained unknown.

METHODS

Two-sample Mendelian randomization (TSMR) was used to investigate the role of PM10, PM2.5, NO2, and NOX (N = 423,796-456,380) in 15 autoimmune diseases (N = 14,890-314,995) using data from large European GWASs including UKB, FINNGEN, IMSGC, and IPSCSG. Multivariable Mendelian randomization (MVMR) was conducted to investigate the direct effect of each air pollutant and the mediating role of common factors, including body mass index (BMI), alcohol consumption, smoking status, and household income. Transcriptome-wide association studies (TWAS), two-step MR, and colocalization analyses were performed to explore underlying mechanisms between air pollution and autoimmune diseases.

RESULTS

In TSMR, after correction of multiple testing, hypothyroidism was causally associated with higher exposure to NO2 [odds ratio (OR): 1.37, p = 9.08 × 10-4] and NOX [OR: 1.34, p = 2.86 × 10-3], ulcerative colitis (UC) was causally associated with higher exposure to NOX [OR: 2.24, p = 1.23 × 10-2] and PM2.5 [OR: 2.60, p = 5.96 × 10-3], rheumatoid arthritis was causally associated with higher exposure to NOX [OR: 1.72, p = 1.50 × 10-2], systemic lupus erythematosus was causally associated with higher exposure to NOX [OR: 4.92, p = 6.89 × 10-3], celiac disease was causally associated with lower exposure to NOX [OR: 0.14, p = 6.74 × 10-4] and PM2.5 [OR: 0.17, p = 3.18 × 10-3]. The risky effects of PM2.5 on UC remained significant in MVMR analyses after adjusting for other air pollutants. MVMR revealed several common mediators between air pollutants and autoimmune diseases. Transcriptional analysis identified specific gene transcripts and pathways interconnecting air pollutants and autoimmune diseases. Two-step MR revealed that POR, HSPA1B, and BRD2 might mediate from air pollutants to autoimmune diseases. POR pQTL (rs59882870, PPH4=1.00) strongly colocalized with autoimmune diseases.

CONCLUSION

This research underscores the necessity of rigorous air pollutant surveillance within public health studies to curb the prevalence of autoimmune diseases.

Harnessing anti-inflammatory pathways and macrophage nano delivery to treat inflammatory and fibrotic disorders

Targeting specific organs and cell types using nanotechnology and sophisticated delivery methods has been at the forefront of applicative biomedical sciences lately. Macrophages are an appealing target for immunomodulation by nanodelivery as they are heavily involved in various aspects of many diseases and are highly plastic in their nature. Their continuum of functional "polarization" states has been a research focus for many years yielding a profound understanding of various aspects of these cells. The ability of monocyte-derived macrophages to metamorphose from pro-inflammatory to reparative and consequently to pro-resolving effectors has raised significant interest in its therapeutic potential. Here, we briefly survey macrophages' ontogeny and various polarization phenotypes, highlighting their function in the inflammation-resolution shift. We review their inducing mediators, signaling pathways, and biological programs with emphasis on the nucleic acid sensing-IFN-I axis. We also portray the polarization spectrum of macrophages and the characteristics of their transition between different subtypes. Finally, we highlighted different current drug delivery methods for targeting macrophages with emphasis on nanotargeting that might lead to breakthroughs in the treatment of wound healing, bone regeneration, autoimmune, and fibrotic diseases.

Inflammation-Responsive Nanoagents for Activatable Photoacoustic Molecular Imaging and Tandem Therapies in Rheumatoid Arthritis

Rheumatoid arthritis (RA) severely lowers the life quality by progressively destructing joint functions and eventually causing permanent disability, representing a pressing public health concern. The pathogenesis of RA includes the excessive production of proinflammatory cytokines and harmful oxygen-derived free radicals, such as nitric oxide (NO), which constitute vital targets for precise diagnosis and effective treatment of RA. In this study, we introduce an advanced nanoagent that integrates the RA microenvironment-activatable photoacoustic (PA) imaging with multitarget synergistic treatment for RA. A highly sensitive organic probe with NO-tunable energy transformation and molecular geometry is developed, which enables strong near-infrared absorption with a turn-on PA signal, and the active intramolecular motion could further boost PA conversion. The probe is coassembled with an inflammation-responsive prodrug to construct the theranostic nanoagent, on which a macrophage-derived cell membrane with natural tropism to the inflammatory sites is camouflaged to improve the targeting ability to inflamed joints. The nanoagent could not only sensitively detect RA and differentiate the severity but also efficiently alleviate RA symptoms and improve joint function. The combination of activatable probe-mediated NO scavenging and on-demand activation of anti-inflammatory prodrug significantly inhibits the proinflammatory factors and promotes macrophage repolarization from M1 to M2 phenotype. This meticulously designed nanoagent ingeniously integrates RA-specific PA molecular imaging with synergistic multitarget therapy, rendering tremendous promise for precise intervention of RA-related diseases.

A Single-Component Dual Donor Enables Ultrasound-Triggered Co-release of Carbon Monoxide and Hydrogen Sulfide

The development of dual gasotransmitter donors can not only provide robust tools to investigate their subtle interplay under pathophysiological conditions but also optimize therapeutic efficacy. While conventional strategies are heavily dependent on multicomponent donors, we herein report an ultrasound-responsive water-soluble copolymer (PSHF) capable of releasing carbon monoxide (CO) and hydrogen sulfide (H2 S) based on single-component sulfur-substituted 3-hydroxyflavone (SHF) derivatives. Interestingly, sulfur substitution can not only greatly improve the ultrasound sensitivity but also enable the co-release of CO/H2 S under mild ultrasound irradiation. The co-release of CO/H2 S gasotransmitters exerts a bactericidal effect against Staphylococcus aureus and demonstrates anti-inflammatory activity in lipopolysaccharide-challenged macrophages. Moreover, the excellent tissue penetration of ultrasound irradiation enables the local release of CO/H2 S in the joints of septic arthritis rats, exhibiting superior therapeutic efficacy without the need for any antibiotics.

Study of hydrogen sulfide biosynthesis in synovial tissue from diabetes-associated osteoarthritis and its influence on macrophage phenotype and abundance

Type 2 diabetes (DB) is an independent risk factor for osteoarthritis (OA). However, the mechanisms underlying the connection between both diseases remain unclear. Synovial macrophages from OA patients with DB present a marked pro-inflammatory phenotype. Since hydrogen sulphide (H₂S) has been previously described to be involved in macrophage polarization, in this study we examined H₂S biosynthesis in synovial tissue from OA patients with DB, observing a reduction of H₂S-synthetizing enzymes in this subset of individuals. To elucidate these findings, we detected that differentiated TPH-1 cells to macrophages exposed to high levels of glucose presented a lower expression of H₂S-synthetizing enzymes and an increased inflammatory response to LPS, showing upregulated expression of markers associated with M1 phenotype (i.e., CD11c, CD86, iNOS, and IL-6) and reduced levels of those related to M2 fate (CD206 and CD163). The co-treatment of the cells with a slow-releasing H₂S donor, GYY-4137, attenuated the expression of M1 markers, but failed to modulate the levels of M2 indicators. GYY-4137 also reduced HIF-1α expression and upregulated the protein levels of HO-1, suggesting their involvement in the anti-inflammatory effects of H₂S induction. In addition, we observed that intraarticular administration of H₂S donor attenuated synovial abundance of CD68⁺ cells, mainly macrophages, in an in vivo model of OA. Taken together, the findings of this study seem to reinforce the key role of H₂S in the M1-like polarization of synovial macrophages associated to OA and specifically its metabolic phenotype, opening new therapeutic perspectives in the management of this pathology.

From Gasotransmitter to Immunomodulator: The Emerging Role of Hydrogen Sulfide in Macrophage Biology

Hydrogen sulfide (H2S) has been increasingly recognized as a crucial inflammatory mediator in immune cells, particularly macrophages, due to its direct and indirect effects on cellular signaling, redox homeostasis, and energy metabolism. The intricate regulation of endogenous H2S production and metabolism involves the coordination of transsulfuration pathway (TSP) enzymes and sulfide oxidizing enzymes, with TSP's role at the intersection of the methionine pathway and glutathione synthesis reactions. Additionally, H2S oxidation mediated by sulfide quinone oxidoreductase (SQR) in mammalian cells may partially control cellular concentrations of this gasotransmitter to induce signaling. H2S is hypothesized to signal through the posttranslational modification known as persulfidation, with recent research highlighting the significance of reactive polysulfides, a derivative of sulfide metabolism. Overall, sulfides have been identified as having promising therapeutic potential to alleviate proinflammatory macrophage phenotypes, which are linked to the exacerbation of disease outcomes in various inflammatory conditions. H2S is now acknowledged to have a significant influence on cellular energy metabolism by affecting the redox environment, gene expression, and transcription factor activity, resulting in changes to both mitochondrial and cytosolic energy metabolism processes. This review covers recent discoveries pertaining to the involvement of H2S in macrophage cellular energy metabolism and redox regulation, and the potential implications for the inflammatory response of these cells in the broader framework of inflammatory diseases.