Potential of Sulforaphane and Broccoli Membrane Vesicles as Regulators of M1/M2 Human Macrophage Activity

Sulforaphane promotes diabetic wound healing by regulating macrophage efferocytosis and polarization

BACKGROUND

Delayed wound healing frequently occurs as a complication of diabetes. Diabetic wounds that are difficult to heal are associated with chronic, persistent inflammation, characterized by impaired efferocytosis and a sustained pro-inflammatory state of macrophages at the wound site. Sulforaphane (SFN), a bioactive compound found in cruciferous vegetables, possesses anti-inflammatory and antioxidant activities. Numerous studies have shown that SFN can inhibit various inflammatory diseases such as atherosclerosis and psoriasis; however, its potential in treating diabetic wounds remains unknown.

PURPOSE

This study investigates the effects and potential mechanisms of SFN on diabetic wound healing.

METHODS

Network pharmacology approaches were employed to identify potential targets of SFN for diabetic wound treatment. Additionally, an STZ-induced diabetic mouse model (C57/B6) was used in in vivo studies to examine SFN's impact on diabetic wound healing. Simultaneously, immunofluorescence staining, immunohistochemical staining, Western blotting, and qPCR analysis were employed to detect phenotypes associated with macrophage efferocytosis and M2 polarization. Subsequently, the mechanism underlying SFN treatment was explored through in vitro experiments utilizing the THP-1 human monocyte cell line.

RESULTS

The results demonstrated that topical SFN application accelerated wound healing in diabetic mice, partly through the enhancement of impaired macrophage efferocytosis and the promotion of M2 macrophage polarization, thereby reducing the inflammatory response at the wound site. SFN promoted the phagocytosis of apoptotic Jurkat cells by THP-1 differentiated macrophages, reducing the resulting inflammatory response. Mechanistic studies revealed that SFN promotes macrophage efferocytosis by activating nuclear factor E2-related factor 2 (Nrf2), leading to upregulation of heme oxygenase 1 (HO-1) expression and subsequent enhancement of mer proto-oncogene tyrosine kinase (MERTK), a recognition receptor for efferocytosis. Furthermore, SFN enhanced macrophage polarization toward the M2 phenotype and reduced the lipopolysaccharide (LPS)-induced inflammatory response in vitro.

CONCLUSION

These data suggest that SFN could serve as an effective adjunct or novel therapeutic agent for treating chronic non-healing wounds in diabetes.

The biphasic role of Hspb1 on ferroptotic cell death in Parkinson's disease

Rationale: Ferroptosis-driven loss of dopaminergic neurons plays a pivotal role in the pathogenesis of Parkinson's disease (PD). In PD patients, Hspb1 is commonly observed at abnormally high levels in the substantia nigra. The precise consequences of Hspb1 overexpression in PD, however, have yet to be fully elucidated. Methods: We used human iPSC-derived dopaminergic neurons and Coniferaldehyde (CFA)-an Nrf2 agonist known for its ability to cross the blood-brain barrier-to investigate the role of Hspb1 in PD. We examined the correlation between Hspb1 overexpression and Nrf2 activation and explored the transcriptional regulation of Hspb1 by Nrf2. Gene deletion techniques were employed to determine the necessity of Nrf2 and Hspb1 for CFA's neuroprotective effects. Results: Our research demonstrated that Nrf2 can upregulate the transcription of Hspb1 by directly binding to its promoter. Deletion of either Nrf2 or Hspb1 gene abolished the neuroprotective effects of CFA. The Nrf2-Hspb1 pathway, newly identified as a defense mechanism against ferroptosis, was shown to be essential for preventing neurodegeneration progression. Additionally, we discovered that prolonged overexpression of Hspb1 leads to neuronal death and that Hspb1 released from ruptured cells can trigger secondary cell death in neighboring cells, exacerbating neuroinflammatory responses. Conclusions: These findings highlight a biphasic role of Hspb1 in PD, where it initially provides neuroprotection through the Nrf2-Hspb1 pathway but ultimately contributes to neurodegeneration and inflammation when overexpressed. Understanding this dual role is crucial for developing therapeutic strategies targeting Hspb1 and Nrf2 in PD.

Sulforaphane decreases oxidative stress and inhibits NLRP3 inflammasome activation in a mouse model of ulcerative colitis

Excessive oxidative stress and NLRP3 inflammasome activation are considered the main drivers of inflammatory bowel disease (IBD), and inhibition of inflammasomes ameliorates clinical symptoms and morphological manifestations of IBD. Herein, we examined the roles of NLRP3 activation in IBD and modulation of NLRP3 by sulforaphane (SFN), a compound with multiple pharmacological activities that is extracted from cruciferous plants. To simulate human IBD, we established a mouse colitis model by administering dextran sodium sulfate in the drinking water. SFN (25, 50 mg·kg-1·d-1, ig) or the positive control sulfasalazine (500 mg/kg, ig) was administered to colitis-affected mice for 7 days. Model mice displayed pathological alterations in colon tissue as well as classic symptoms of colitis beyond substantial tissue inflammation. Expression of NLRP3, ASC, and caspase-1 was significantly elevated in the colonic epithelium. The expression of NLRP3 inflammasomes led to activation of downstream proteins and increases in the cytokines IL-18 and IL-1β. SFN administration either fully or partially reversed these changes, thus restoring IL-18 and IL-1β, substantially inhibiting NLRP3 activation, and decreasing inflammation. SFN alleviated the inflammation induced by LPS and NLRP3 agonists in RAW264.7 cells by decreasing the levels of reactive oxygen species. In summary, our results revealed the pathological roles of oxidative stress and NLRP3 in colitis, and indicated that SFN might serve as a natural NLRP3 inhibitor, thereby providing a new strategy for alternative colitis treatment.

Regulation of immunomodulatory networks by Nrf2-activation in immune cells: Redox control and therapeutic potential in inflammatory diseases

Inflammatory diseases present a serious health challenge due to their widespread prevalence and the severe impact on patients' lives. In the quest to alleviate the burden of these diseases, nuclear factor erythroid 2-related factor 2 (Nrf2) has emerged as a pivotal player. As a transcription factor intimately involved in cellular defense against metabolic and oxidative stress, Nrf2's role in modulating the inflammatory responses of immune cells has garnered significant attention. Recent findings suggest that Nrf2's ability to alter the redox status of cells underlies its regulatory effects on immune responses. Our review delves into preclinical and clinical evidence that underscores the complex influence of Nrf2 activators on immune cell phenotypes, particularly in the inflammatory milieu. By offering a detailed analysis of Nrf2's role in different immune cell populations, we cast light on the potential of Nrf2 activators in shaping the immune response towards a more regulated state, mitigating the adverse effects of inflammation through modeling redox status of immune cells. Furthermore, we explore the innovative use of nanoencapsulation techniques that enhance the delivery and efficacy of Nrf2 activators, potentially advancing the treatment strategies for inflammatory ailments. We hope this review will stimulate the development and expansion of Nrf2-targeted treatments that could substantially improve outcomes for patients suffering from a broad range of inflammatory diseases.