MAPKs and NF‑κB pathway inhibitory effect of bisdemethoxycurcumin on phorbol‑12‑myristate‑13‑acetate and A23187‑induced inflammation in human mast cells

Diospyros malabarica (Desr.) Kostel fruits extract attenuated acute and chronic inflammation through modulation of the expression of pro- and anti-inflammatory biomarkers in rat models

Rheumatoid arthritis is a chronic inflammatory disorder of polyarticular tissues, characterised by progressive synovitis. Its prolonged treatment imparts a huge burden on the healthcare system and results in toxicity, which necessitates the search for safe, efficacious and cost-effective therapies. Diospyros malabarica (Desr.) Kostel is traditionally used for anti-inflammatory purposes; however, to the best of our knowledge, there is no detailed study reporting the in vivo anti-inflammatory potential of this plant. Therefore, in the current study, the methanol extract of D. malabarica (Desr.) Kostel fruit (mDMF) was evaluated for its antioxidant, anti-inflammatory and anti-arthritic potentials, along with its underlying mechanisms. The antioxidant activity was evaluated by DPPH assay. Total phenolic and flavonoid contents were estimated via colorimetric and high-performance liquid chromatography (HPLC) methods. Different doses (250, 500 and 750 mg/kg) of mDMF were used to evaluate the anti-inflammatory and anti-arthritis actions in acute inflammatory (carrageenan and histamine-induced paw oedema) and Freund's complete adjuvant (FCA)-induced arthritis rat models. Levels of various pro- and anti-inflammatory biomarkers were estimated using ELISA and RT-PCR techniques. Paw samples were used for different histopathological and radiographic studies. Qualitative phytochemical and HPLC analyses indicated the presence of various polyphenolic compounds in mDMF, which exhibited marked antioxidant activity in the DPPH assay. mDMF showed time-dependent anti-inflammatory and anti-arthritic effects in in vivo models. ELISA assay data showed significant (p < 0.05) reduction in the serum levels of C-reactive protein and rheumatoid factor in the mDMF treatment groups. RT-PCR data showed significant (p < 0.05) down-regulation of various pro-inflammatory markers (TNF-α, NF-κB, COX-2, IL-1β and IL-6) and up-regulation of anti-inflammatory markers (IκB, IL-4 and IL-10) in serum samples of rats treated with mDMF. The histopathology of the ankle joints showed reduced pannus formation, joint swelling and synovial hyperplasia in mDMF-treated animals when compared with the untreated disease control group. Overall, it may be concluded that the antioxidant, anti-inflammatory and anti-arthritis properties of mDMF are due to its flavonoid and phenolic constituents. Further studies using a stable oral dosage form of D. malabarica (Desr.) Kostel fruits extract are warranted to explore its effects in other inflammatory disorders, including irritable bowel syndrome, appendicitis and hepatitis.

Targeting Mast Cells in Allergic Disease: Current Therapies and Drug Repurposing

The incidence of allergic disease has grown tremendously in the past three generations. While current treatments are effective for some, there is considerable unmet need. Mast cells are critical effectors of allergic inflammation. Their secreted mediators and the receptors for these mediators have long been the target of allergy therapy. Recent drugs have moved a step earlier in mast cell activation, blocking IgE, IL-4, and IL-13 interactions with their receptors. In this review, we summarize the latest therapies targeting mast cells as well as new drugs in clinical trials. In addition, we offer support for repurposing FDA-approved drugs to target mast cells in new ways. With a multitude of highly selective drugs available for cancer, autoimmunity, and metabolic disorders, drug repurposing offers optimism for the future of allergy therapy.

Bisdemethoxycurcumin attenuates OVA‑induced food allergy by inhibiting the MAPK and NF‑κB signaling pathways

Bisdemethoxycurcumin (BDMC) is an important ingredient derived from turmeric in addition to curcumin. It has been reported that BDMC can be used to treat mast cell-mediated allergic diseases. In the present study, a food allergy (FA) murine model sensitized by intraperitoneal injection followed by oral challenge with ovalbumin (OVA) was established. BDMC was orally administered at 100 and 200 mg/kg for 11 days in the challenge phase to treat OVA-induced FA mice. FA symptoms such as diarrhea score, anaphylactic symptom score and rectal temperature were recorded. Intestinal tissue was also observed by hematoxylin and eosin staining. In addition, other allergic indicators were also analyzed by ELISA and western blot analysis. The present study demonstrated that BDMC could suppress the decreases in rectal temperature, diarrhea and anaphylactic symptoms in FA mice. BDMC could also ameliorate the inflammation of intestinal tissues in FA mice. BDMC not only decreased the production of OVA-specific immunoglobulin (OVA-sIg)E, IgG1, histamine, mouse mast cell protease-1, diamine oxidase, cytokines (IL-4, IL-5 and IL-13) but increased cytokines interferon-γ production. The protein expression results showed that the levels of Gata-3 were decreased but T-bet levels were increased. Furthermore, compared with the OVA group, phosphorylated (p)-p38, p-JNK, p-ERK and p-NF-κBp65 levels were decreased and p-IκBα level was increased. In conclusion, the results showed that BDMC possessed a protective effect on FA. Furthermore, BDMC was able to regulate the T-helper cells (Th)1/Th2 immune balance and inhibit the activation of MAPK and NF-κB pathways in FA mice.

Anti-Inflammatory Efficacy of Curcumin as an Adjunct to Non-Surgical Periodontal Treatment: A Systematic Review and Meta-Analysis

Objective: Curcumin has been used as an adjunct to non-surgical periodontal treatment. However, the efficacy of curcumin in the periodontal therapy remained controversial. This study aimed to evaluate the anti-inflammatory efficacy of curcumin as an adjunct to non-surgical periodontal treatment (NPT) by systematic review.

Methods: Databases including Embase, PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov were searched to identify relevant RCTs on the use of curcumin as an adjunct to NPT for the treatment of periodontal disease from inception to July 21, 2021. Two reviewers independently screened literature, extracted data and assessed the risk of bias of the included studies. Meta-analysis was then performed using Review Manager 5.3 software.

Results: A total of 18 RCTs involving 846 patients/sites were included in this meta-analysis. The results of the meta-analysis revealed that as compared to NPT alone, curcumin as an adjunct to NPT resulted in significant reduction in gingival index (GI) at the 1-week (mean differences (MD) = −0.15, 95% confidence intervals (CI) −0.26 to −0.05, p = 0.005), 2-week (MD = −0.51, 95%CI −0.74 to −0.28, p &lt; 0.0001), 3-week (MD = −0.34, 95%CI −0.66 to −0.02, p = 0.03), 4-week (MD = −0.25, 95%CI −0.48 to −0.02, p = 0.04) or 6-week (MD = −0.33, 95%CI −0.58 to −0.08, p = 0.01) follow-ups. Similar significant reductions were also observed for sulcus bleeding index (SBI) at 1, 2, 4, and 12 weeks. However, there were no statistically significant differences in reducing bleeding on probing (BOP) between curcumin as an adjunct and NPT alone at 4, 12, and 24 weeks.

Conclusion: Based on the current evidence, curcumin demonstrates anti-inflammatory efficacies in terms of reducing GI and SBI compared with NPT alone. Moreover, curcumin is a natural herbal medicine with few side effects, and it is a good candidate as an adjunct treatment for periodontal disease.

Bisdemethoxycurcumin attenuates lipopolysaccharide-induced intestinal damage through improving barrier integrity, suppressing inflammation, and modulating gut microbiota in broilers

Bisdemethoxycurcumin has good antioxidant and anti-inflammatory effects and has been widely used as food and feed supplements in the form of curcuminoids. However, the beneficial effect of individual bisdemethoxycurcumin on preventing lipopolysaccharide (LPS)-induced inflamed intestinal damage is unclear. The present study aimed to investigate whether dietary bisdemethoxycurcumin supplementation could attenuate LPS-induced intestinal damage and alteration of cecal microbiota in broiler chickens. In total, 320 one-day-old male Arbor Acres broiler chickens with a similar weight were randomly divided into four treatments. The treatments were designed as a 2 × 2 factorial arrangement: basal diet (CON); 150 mg/kg bisdemethoxycurcumin diet (BUR); LPS challenge + basal diet (LPS); LPS challenge + 150 mg/kg bisdemethoxycurcumin diet (L-BUR). Results showed that dietary bisdemethoxycurcumin supplementation attenuated the LPS-induced decrease of average daily feed intake. LPS challenge compromised the intestinal morphology and disrupted the intestinal tight junction barrier. Dietary bisdemethoxycurcumin supplementation significantly increased villus length:crypt depth ratio and upregulated the mRNA expression of intestinal tight junction proteins. Moreover, a remarkably reduced mRNA expression of inflammatory mediators was observed following bisdemethoxycurcumin supplementation. The cecal microbiota analysis showed that bisdemethoxycurcumin supplementation increased the relative abundance of the genus Faecalibacterium while decreased the relative abundance of the genera Bacteroides and Subdoligranulum. In conclusion, dietary bisdemethoxycurcumin supplementation could counteract LPS-induced inflamed intestinal damage in broiler chickens by improving intestinal morphology, maintaining intestinal tight junction, downregulating pro-inflammatory mediators, and restoring cecal microbiota.

The Immunomodulatory and Anti-Inflammatory Effect of Curcumin on Immune Cell Populations, Cytokines, and In Vivo Models of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a widespread chronic autoimmune disorder affecting the joints, causing irreversible cartilage, synovium, and bone degradation. During the course of the disease, many immune and joint cells are activated, causing inflammation. Immune cells including macrophages, lymphocytes, neutrophils, mast cells, natural killer cells, innate lymphoid cells, as well as synovial tissue cells, like fibroblast-like synoviocytes, chondrocytes, and osteoclasts secrete different proinflammatory factors, including many cytokines, angiogenesis-stimulating molecules and others. Recent studies reveal that curcumin, a natural dietary anti-inflammatory compound, can modulate the response of the cells engaging in RA course. This review comprises detailed data about the pathogenesis and inflammation process in rheumatoid arthritis and demonstrates scientific investigations about the molecular interactions between curcumin and immune cells responsible for rheumatoid arthritis development to discuss this herbal drug’s immunoregulatory role in RA treatment.

Protein Kinase C Regulates ASIC1a Protein Expression and Channel Function via NF-kB Signaling Pathway

Tissue acidosis is a common feature in many pathological conditions. Activation of acid-sensing ion channel 1a (ASIC1a) plays a key role in acidosis-mediated neurotoxicity. Protein kinase C (PKC) activity has been proved to be associated with many physiological processes and pathological conditions; however, whether PKC activation regulates ASIC1a protein expression and channel function remains ill defined. In this study, we demonstrated that treatment with phorbol 12-myristate 13-acetate (PMA, a PKC activator) for 6 h significantly increased ASIC1a protein expression and ASIC currents in NS20Y cells, a neuronal cell line, and in primary cultured mouse cortical neurons. In contrast, treatment with Calphostin C (a nonselective PKC inhibitor) for 6 h or longer decreased ASIC1a protein expression and ASIC currents. Similar to Calphostin C, PKC α and βI inhibitor Go6976 exposure also reduced ASIC1a protein expression. The reduction in ASIC1a protein expression by PKC inhibition involves a change in ASIC1a protein degradation, which is mediated by ubiquitin-proteasome system (UPS)-dependent degradation pathway. In addition, we showed that PKC regulation of ASIC1a protein expression involves NF-κB signaling pathway. Consistent with their effects on ASIC1a protein expression and channel function, PKC inhibition protected NS20Y cells against acidosis-induced cytotoxicity, while PKC activation potentiated acidosis-induced cells injury. Together, these results indicate that ASIC1a protein expression and channel function are closely regulated by the activity of protein kinase C and its downstream signaling pathway(s).

Therapeutic effect of Bacillus Calmette-Guerin polysaccharide nucleic acid on mast cell at the transcriptional level

Background

Chronic spontaneous urticaria (CSU) is a common and recurrent autoimmune-related disease with unclear pathogenesis. Dysfunction of immune cells, such as T cells, mast cells, and basophils, is involved. Bacillus Calmette-Guerin polysaccharide nucleic acid (BCG-PSN), an immunomodulator partially extracted from BCG, can be used in the combined treatment of CSU with an unknown mechanism.

Methods

To study the therapeutic effect and mechanism of BCG-PSN on CSU, we initially assessed the clinical efficacy in 110 enrolled CSU patients of 4-week antihistamine monotherapy vs. antihistamine plus BCG-PSN combined therapy. Subsequently, to explore the further mechanism of BCG-PSN, the mast cell line RBL-2H3 pretreated with BCG-PSN was used to evaluate the transcriptional expression profiles via lncRNA sequencing. Real time PCR was conducted to validate the candidate gene expression.

Results

We found no significant difference in treatment efficacy between the BCG-PSN group (71.7%) and the monotherapy group (71.9%). However, the average time of complete relief in the BCG-PSN group was significantly shorter than that in the monotherapy group (36.77 ± 17.33 vs. 51.27 ± 16.80, p = 0.026). In vitro experiments showed that BCG-PSN inhibited β-hexosaminidase release rates in IgE-sensitized RBL-2H3 cells (p < 0.001). Sequencing data revealed the expression profiles of functional genes, including a significant decrease in Erb-B2 receptor tyrosine kinase 4, which can be regulated by the nuclear factor kappa B (NF-κB) pathway.

Discussion

CSU is a chronic, recurrent disease with complex pathogenesis. Mast cells and basophils are the primary target cells of the disease. BCG-PSN decrease the β-HEX release rates and regulated IgE-mediated mast cell activation in RBL-2H3 cells by mediating immune-related gene expression including ERBB4. These findings suggest that BCG-PSN may mediate ERBB4 expression via the NF-κB pathway and may have value in the treatment of CSU.