N-Butyrylated Hyaluronic Acid Achieves Anti-Inflammatory Effects In Vitro and in Adjuvant-Induced Immune Activation in Rats

Menisoxoisoaporphine A, a novel oxoisoaporphine alkaloid from Menispermi Rhizoma, inhibits inflammation by targeting PDE4B

Background

Dysregulated and excessive inflammatory reactions can lead to tissue damage, which is the underlying cause of most human diseases. Menisoxoisoaporphine A (MA), a novel oxoisoaporphine alkaloid, was obtained from Menispermi Rhizoma, a traditional Chinese medicinal herb used in the treatment of inflammatory conditions in clinical practice. This suggests that MA has very promising potential for the development of anti-inflammatory therapeutics. Hence, this study aims to investigate the anti-inflammatory effects and underlying mechanisms of MA.

Method

The anti-inflammatory effects of MA were evaluated in lipopolysaccharide (LPS)-induced mouse macrophage RAW264.7 cells. Its underlying mechanisms were explored through RNA sequencing and Western blotting. The binding modes and interactions sites between MA and phosphodiesterase 4B (PDE4B) were predicted using molecular docking and validated by molecular dynamics simulation.

Results

MA treatment significantly reduced LPS-induced morphological changes, inflammatory cytokine relesae, and proinflammatory genes expression in RAW264.7 cells compared to the LPS-induced controls. Transcriptome sequencing analysis suggested that PDE4B might be a key target for MA to exert its therapeutic effect. Mechanismly, MA directly acted on Tyr405 site of PDE4B, thus leading to a sustained elevation of the cyclic adenosine monophosphate (cAMP) levels, which subsequently inactivated NF-κB signaling pathway by phosphorylating protein kinase A (PKA). MA inhibited the NF-κB-mediated inflammatory response depending on PDE4B.

Conclusion

MA, a natural and novel compound, exerted anti-inflammatory effects in LPS-induced RAW264.7 macrophage cells. It demonstrated a strong binding ability to the Tyr405 sites of PDE4B, thereby inhibiting NF-κB signaling pathway by regulating the cAMP-PKA axis. Elucidating the interaction between MA and PDE4B holds significant potential for the advancement of innovative therapeutic strategies aimed at inflammatory diseases. By strategically modulating this interaction, it may be feasible to achieve more precise regulation of inflammatory responses, thereby offering promising therapeutic benefits for conditions such as rheumatoid arthritis, asthma, and inflammatory bowel disease.

Advancements in the study of IL-6 and its receptors in the pathogenesis of gout

Gout is an autoinflammatory disease characterized by the deposition of monosodium urate crystals in or around the joints, primarily manifesting as inflammatory arthritis that recurs and resolves spontaneously. Interleukin-6 (IL-6) is a versatile cytokine with both anti-inflammatory and pro-inflammatory capabilities, linked to a variety of inflammatory diseases such as gouty arthritis, rheumatoid arthritis, inflammatory bowel disease, vasculitis, and several types of cancer. The rapid production of IL-6 during infections and tissue damage aids in host defense. However, excessive synthesis of IL-6 and dysregulation of its receptor signaling (IL-6R) might contribute to the pathology of diseases. Recent advancements in clinical and basic research, along with developments in animal models, have established the significant role of IL-6 and its receptors in the pathogenesis of gout, although the precise mechanisms remain to be fully elucidated. This review discusses the role of IL-6 and its receptors in gout progression and examines contemporary research on modulating IL-6 and its signaling pathways for treatment. It aims to provide insights into the pathogenesis of gout and to advance the development of targeted therapies for gout-related inflammation.

Rapid Characterization of the Potential Active of Sinomenine in Rats by Ultra-High-Performance Liquid Chromatography-Quadrupole-Exactive Orbitrap Mass Spectrometry and Molecular Docking

Sinomenium acutum (Thunb.) Rehd. et Wils is widely used in the treatment of rheumatoid arthritis, with its alkaloid compound sinomenine (SIN) being renowned for its significant anti-inflammatory properties. However, despite its widespread application, the in vivo anti-inflammatory mechanisms and metabolic pathways of SIN remain incompletely understood. This study established a rapid and reliable method based on an ultra-high-performance liquid chromatography method coupled with Quadrupole-Exactive Orbitrap mass spectrometry and molecular docking to identify and characterize SIN and 69 metabolites in rat plasma, urine, and feces, revealing primary metabolic pathways of hydroxylation, demethylation, sulfation, and glucuronidation. Molecular docking results revealed that phase I reactions, including dedimethylation, demethylation, dehydrogenation, and dihydroxylation, along with their composite reactions, were pivotal in influencing SIN's in vivo anti-inflammatory activity. M28, M36, and M59 are potentially the most anti-inflammatory active metabolites of SIN in vivo. This comprehensive analysis unveils SIN's metabolic pathways, offering insights into its biological processes and suggesting a novel approach for exploring active drug constituents. These findings pave the way for further understanding SIN's anti-inflammatory mechanisms, contributing significantly to the development of new therapeutic strategies.

Osteoarthritis: Insights into Diagnosis, Pathophysiology, Therapeutic Avenues, and the Potential of Natural Extracts

Osteoarthritis (OA) stands as a prevalent and progressively debilitating clinical condition globally, impacting joint structures and leading to their gradual deterioration through inflammatory mechanisms. While both non-modifiable and modifiable factors contribute to its onset, numerous aspects of OA pathophysiology remain elusive despite considerable research strides. Presently, diagnosis heavily relies on clinician expertise and meticulous differential diagnosis to exclude other joint-affecting conditions. Therapeutic approaches for OA predominantly focus on patient education for self-management alongside tailored exercise regimens, often complemented by various pharmacological interventions primarily targeting pain alleviation. However, pharmacological treatments typically exhibit short-term efficacy and local and/or systemic side effects, with prosthetic surgery being the ultimate resolution in severe cases. Thus, exploring the potential integration or substitution of conventional drug therapies with natural compounds and extracts emerges as a promising frontier in enhancing OA management. These alternatives offer improved safety profiles and possess the potential to target specific dysregulated pathways implicated in OA pathogenesis, thereby presenting a holistic approach to address the condition's complexities.

Glutamic-acid grafted hyaluronic acid inhibits inflammatory factors via fibroblast and skin model tests

BACKGROUND

Excessive inflammation may cause tissue damage and disrupt the function of the skin barrier. Hyaluronic acid (HA), an endogenous component, was found to regulate multiple inflammatory factors for skin health. This work aims to further enhance its efficacy by grafting amino acid onto its molecule.

METHODS

Glutamic acid (Glu) was selected as the ligand to react with low-molecular-weight HA. Fibroblast tests and a 3D skin model were used to investigate the anti-inflammation efficacy of HA-Glu.

RESULTS

For IL-1α, IL-6 and TNF-α, the grafted compound presents stronger inhibition ability versus native HA. Moreover, HA-Glu could promote the repair of damaged skin by improving the compactness of the stratum corneum and increasing the thickness of the living cell layer.

CONCLUSION

The application of HA-Glu compound in skin care formulas would be effective to alleviate inflammation-induced skin symptoms and skin aging.

The dysregulation of immune cells induced by uric acid: mechanisms of inflammation associated with hyperuricemia and its complications

Changes in lifestyle induce an increase in patients with hyperuricemia (HUA), leading to gout, gouty arthritis, renal damage, and cardiovascular injury. There is a strong inflammatory response in the process of HUA, while dysregulation of immune cells, including monocytes, macrophages, and T cells, plays a crucial role in the inflammatory response. Recent studies have indicated that urate has a direct impact on immune cell populations, changes in cytokine expression, modifications in chemotaxis and differentiation, and the provocation of immune cells by intrinsic cells to cause the aforementioned conditions. Here we conducted a detailed review of the relationship among uric acid, immune response, and inflammatory status in hyperuricemia and its complications, providing new therapeutic targets and strategies.

Hyaluronan and Reactive Oxygen Species Signaling—Novel Cues from the Matrix?

Hyaluronan (HA) is a naturally occurring non-sulfated glycosaminoglycan (GAG) localized to the cell surface and the tissue extracellular matrix (ECM). It is composed of disaccharides containing glucuronic acid and N-acetylglucosamine, is synthesized by the HA synthase (HAS) enzymes and is degraded by hyaluronidase (HYAL) or reactive oxygen and nitrogen species (ROS/RNS) actions. HA is deposited as a high molecular weight (HMW) polymer and degraded to low molecular weight (LMW) fragments and oligosaccharides. HA affects biological functions by interacting with HA-binding proteins (hyaladherins). HMW HA is anti-inflammatory, immunosuppressive, and antiangiogenic, whereas LMW HA has pro-inflammatory, pro-angiogenetic, and oncogenic effects. ROS/RNS naturally degrade HMW HA, albeit at enhanced levels during tissue injury and inflammatory processes. Thus, the degradation of endothelial glycocalyx HA by increased ROS challenges vascular integrity and can initiate several disease progressions. Conversely, HA exerts a vital role in wound healing through ROS-mediated HA modifications, which affect the innate immune system. The normal turnover of HA protects against matrix rigidification. Insufficient turnover leads to increased tissue rigidity, leading to tissue dysfunction. Both endogenous and exogenous HMW HA have a scavenging capacity against ROS. The interactions of ROS/RNS with HA are more complex than presently perceived and present an important research topic.

Abrocitinib Attenuates Microglia-Mediated Neuroinflammation after Traumatic Brain Injury via Inhibiting the JAK1/STAT1/NF-κB Pathway

BACKGROUND AND PURPOSE

Neuroinflammation has been shown to play a critical role in secondary craniocerebral injury, leading to poor outcomes for TBI patients. Abrocitinib, a Janus kinase1 (JAK1) selective inhibitor approved to treat atopic dermatitis (AD) by the Food and Drug Administration (FDA), possesses a novel anti-inflammatory effect. In this study, we investigated whether abrocitinib could ameliorate neuroinflammation and exert a neuroprotective effect in traumatic brain injury (TBI) models.

METHODS

First, next-generation sequencing (NGS) was used to select genes closely related to neuroinflammation after TBI. Then, magnetic resonance imaging (MRI) was used to dynamically observe the changes in traumatic focus on the 1st, 3rd, and 7th days after the induction of fluid percussion injury (FPI). Moreover, abrocitinib's effects on neurobehaviors were evaluated. A routine peripheral blood test was carried out and Evans blue dye extravasation, cerebral cortical blood flow, the levels of inflammatory cytokines, and changes in the numbers of inflammatory cells were evaluated to investigate the function of abrocitinib on the 1st day post-injury. Furthermore, the JAK1/signal transducer and activator of transcription1 (STAT1)/nuclear factor kappa (NF-κB) pathway was assessed.

RESULTS

In vivo, abrocitinib treatment was found to shrink the trauma lesions. Compared to the TBI group, the abrocitinib treatment group showed better neurological function, less blood-brain barrier (BBB) leakage, improved intracranial blood flow, relieved inflammatory cell infiltration, and reduced levels of inflammatory cytokines. In vitro, abrocitinib treatment was shown to reduce the pro-inflammatory M1 microglia phenotype and shift microglial polarization toward the anti-inflammatory M2 phenotype. The WB and IHC results showed that abrocitinib played a neuroprotective role by restraining JAK1/STAT1/NF-κB levels after TBI.

CONCLUSIONS

Collectively, abrocitinib treatment after TBI is accompanied by improvements in neurological function consistent with radiological, histopathological, and biochemical changes. Therefore, abrocitinib can indeed reduce excessive neuroinflammation by restraining the JAK1/STAT1/NF-κB pathway.