Corrigendum: Unveiling the therapeutic potential of exogenous β-hydroxybutyrate for chronic colitis in rats: novel insights on autophagy, apoptosis, and pyroptosis

[This corrects the article DOI: 10.3389/fphar.2023.1239025.].

Design and construction of novel pyridine-pyrimidine hybrids as selective COX-2 suppressors: anti-inflammatory potential, ulcerogenic profile, molecular modeling and ADME/Tox studies

NSAIDs represent a mainstay in pain and inflammation suppression, and their actions are mainly based on inhibiting COX-1 and COX-2 enzymes.Due to the adverse effects of these drugs, especially on the stomach and heart, scientists efforts have been directed to manufacture selective COX-2 without cardiovascular side effects and with minimal effects on the stomach. The cardiovascular side effects are thought to be related to the chemical composition rather than mechanism of action of these drugs.Novel pyridopyrimidines, 9a-j, were prepared and their chemical structures were confirmed by NMR, mass and IR Spectra, and elemental analysis. The effect of the 9a-j compounds on COX-1 and COX-2 was assessed and it was found that 2-hydrazino-5-(4-methoxyphenyl)-7-phenyl-3H-pyrido[2,3-d)pyrimidin-4-one (9d) was the most potent COX-2 inhibitor (IC50 = 0.54 uM) compared to celecoxib (IC50 = 1.11 uM) with selectivity indices of 6.56 and 5.12, respectively.The in vivo inhibition of paw edema of novel compounds 9a-j was measured using carrageenan-induced paw edema method, and that 2-hydrazino-5-(4-methoxyphenyl)-7-phenyl-3H-pyrido[2,3-d)pyrimidin-4-one (9d) showed the best inhibitory activity in comparison with the other compounds and celecoxib.The gastroprotective effect of the potent derivatives 9d, 9e, 9f, 9 g and 9h was investigated. 2-Hydrazino-5-(4-methoxyphenyl)-7-phenyl-3H-pyrido[2,3-d)pyrimidin-4-one (9d) and 7-(chlorophenyl)-hydrazino-5-(4-methoxyphenyl)-3H-pyrido[2,3-d)pyrimidin-4-one (9e) showed ulcer indices comparable to celecoxib (1 and 0.5 vs 0.5, respectively). Docking studies were carried out and they confirmed the mechanistic action of the designed compoundsCommunicated by Ramaswamy H. Sarma.

Piperidine: A Versatile Heterocyclic Ring for Developing Monoamine Oxidase Inhibitors

The monoamine oxidase enzyme (MAO), which is bound on the membrane of mitochondria, catalyzes the oxidative deamination of endogenous and exogenous monoamines, including monoamine neurotransmitters such as serotonin, adrenaline, and dopamine. These enzymes have been proven to play a significant role in neurodegeneration; thus, they have recently been researched as prospective therapeutic targets for neurodegenerative illness treatment and management. MAO inhibitors have already been marketed as neurodegeneration illness treatments despite their substantial side effects. Hence, researchers are concentrating on developing novel molecules with selective and reversible inhibitory properties. Piperine, which is a phytochemical component present in black pepper, has been established as a potent MAO inhibitor. Piperine encompasses a piperidine nucleus with antibacterial, anti-inflammatory, antihypertensive, anticonvulsant, antimalarial, antiviral, and anticancer properties. The current Review focuses on the structural changes and structure-activity relationships of piperidine derivatives as MAO inhibitors.

WITHDRAWN: Vinpocetine and Lactobacillus improve fatty liver in rats via modulating the oxidative stress, inflammation, adiponectin and gut microbiome

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/policies/article-withdrawal.

Geraniol Suppresses Oxidative Stress, Inflammation, and Interstitial Collagenase to Protect against Inflammatory Arthritis

Geraniol (GER) is a plant-derived acyclic isoprenoid monoterpene that has displayed anti-inflammatory effects in numerous in vivo and in vitro models. This study was therefore designed to evaluate the antiarthritic potential of GER in complete Freund's adjuvant (CFA)-induced inflammatory arthritis (IA) model in rats. IA was induced by intraplantar injection of CFA (0.1 mL), and a week after CFA administration, rats were treated with various doses of methotrexate (MTX; 1 mg/kg) or GER (25, 50, and 100 mg/kg). Treatments were given on every alternate day, and animals were sacrificed on the 35th day. Paw volume, histopathological, hematological, radiographic, and qPCR analyses were performed to analyze the severity of the disease. GER significantly reduced paw edema after 35 days of treatment, and these results were comparable to the MTX-treated group. GER-treated animals displayed a perfect joint structure with minimal inflammation and no signs of cartilage or bone damage. Moreover, GER restored red blood cell and hemoglobin levels, normalized erythrocyte sedimentation rate, platelet, and c-reactive protein values, and also attenuated the levels of rheumatoid factor. RT-qPCR analysis demonstrated that GER decreased mRNA expression of pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta. GER also down-regulated the transcript levels of cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1, prostaglandin D2 synthase, and interstitial collagenase (MMP-1). Molecular docking of GER with COX-2, TNF-α, and MMP-1 also revealed that the antiarthritic effects of GER could be due to its direct interactions with these mediators. Based on our findings, it is conceivable that the antiarthritic effects of GER could be attributed to downregulation of pro-inflammatory mediators and protease like MMP-1.

Unveiling the therapeutic potential of exogenous β-hydroxybutyrate for chronic colitis in rats: novel insights on autophagy, apoptosis, and pyroptosis

Ulcerative colitis (UC) is a chronic relapsing inflammatory disease of the colorectal area that demonstrates a dramatically increasing incidence worldwide. This study provides novel insights into the capacity of the exogenous β-hydroxybutyrate and ketogenic diet (KD) consumption to alleviate dextran sodium sulfate (DSS)-induced UC in rats. Remarkably, both interventions attenuated disease activity and colon weight-to-length ratio, and improved macro and microstructures of the damaged colon. Importantly, both β-hydroxybutyrate and KD curbed the DSS-induced aberrant NLRP3 inflammasome activation as observed in mRNA and protein expression analysis. Additionally, inhibition of the NLRP3/NGSDMD-mediated pyroptosis was detected in response to both regimens. In parallel, these modalities attenuated caspase-1 and its associated consequences of IL-1β and IL-18 overproduction. They also mitigated apoptosis as indicated by the inactivation of caspase-3. The anti-inflammatory effects of BHB and KD were confirmed by the reported decline in the levels of inflammatory markers including MPO, NFκB, IL-6, and TNF-α. Moreover, these interventions exhibited antioxidative properties by reducing ROS production and improving antioxidative enzymes. Their effectiveness in mitigating UC was also evident in the renovation of normal intestinal epithelial barrier function, as shown by correcting the discrepancies in the levels of tight junction proteins ZO-1, OCLN, and CLDN5. Furthermore, their effects on the intestinal microbiota homeostasis were investigated. In terms of autophagy, exogenous β-hydroxybutyrate upregulated BECN-1 and downregulated p62, which may account for its superiority over KD in attenuating colonic damage. In conclusion, this study provides experimental evidence supporting the potential therapeutic use of β-hydroxybutyrate or β-hydroxybutyrate-boosting regimens in UC.

Corrigendum: Mitigation of acetaminophen-induced liver toxicity by the novel phosphatidylinositol 3-kinase inhibitor alpelisib

[This corrects the article DOI: 10.3389/fphar.2023.1212771.].

Assembling a Cinnamyl Pharmacophore in the C3-Position of Substituted Isatins via Microwave-Assisted Synthesis: Development of a New Class of Monoamine Oxidase-B Inhibitors for the Treatment of Parkinson's Disease

Monoamine oxidase (MAO, EC 1.4.3.4) is responsible for the oxidative breakdown of both endogenous and exogenous amines and exists in MAO-A and MAO-B isomers. Eighteen indole-based phenylallylidene derivatives were synthesized via nucleophilic addition reactions comprising three sub-series, IHC, IHMC, and IHNC, and were developed and examined for their ability to inhibit MAO. Among them, compound IHC3 showed a strong MAO-B inhibitory effect with an IC50 (half-maximal inhibitory concentration) value of 1.672 μM, followed by IHC2 (IC50 = 16.934 μM). Additionally, IHC3 showed the highest selectivity index (SI) value of >23.92. The effectiveness of IHC3 was lower than the reference pargyline (0.14 μM); however, the SI value was higher than pargyline (17.16). Structurally, the IHC (-H in the B-ring) sub-series exhibited relatively stronger MAO-B inhibition than the others. In the IHC series, IHC3 (-F in the A-ring) exhibited stronger MAO-B suppression than the other substituted derivatives in the order -F > -Br > -Cl > -OCH3, -CH3, and -H at the 2-position in the A-ring. In the reversibility and enzyme kinetics experiments, IHC3 was a reversible inhibitor with a Ki value of 0.51 ± 0.15 μM for MAO-B. Further, it was observed that IHC3 greatly decreased the cell death caused by rotenone in SH-SY5Y neuroblastoma cells. A molecular docking study of the lead molecule was also performed to determine hypothetical interactions in the enzyme-binding cavity. These findings suggest that IHC3 is a strong, specific, and reversible MAO-B inhibitor that can be used to treat neurological diseases.

Mitigation of acetaminophen-induced liver toxicity by the novel phosphatidylinositol 3-kinase inhibitor alpelisib

The sterile inflammatory response mediated by Toll-like receptors (TLRs) 4 and 9 is implicated in the massive hepatic damage caused by acetaminophen (APAP)-overdose. There is a crosstalk between TLR-dependent signaling with other intracellular kinases like phosphatidylinositol 3-kinases (PI3Ks). Nevertheless, the detailed role of PI3Kα is still unknown in hepatic sterile inflammation. Accordingly, the effect of the novel PI3Kα inhibitor alpelisib was investigated in the setting of APAP-driven sterile inflammation in the liver. This was examined by pretreating mice with alpelisib (5 and 10 mg/kg, oral) 2 h before APAP (500 mg/kg, i.p.)-intoxication. The results indicated that alpelisib dose-dependently lowered APAP-induced escalation in serum liver function biomarkers and hepatic necroinflammation score. Alpelisib also attenuated APAP-induced rise in cleaved caspase 3 and proliferating cell nuclear antigen (PCNA) in the liver hepatocytes, as indices for apoptosis and proliferation. Mechanistically, inhibition of PI3Kα by alpelisib limited APAP-induced overproduction of the pro-inflammatory tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in the blood circulation via switching off the activation of several signal transduction proteins, including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), signal transducer and activator of transcription-3 (Stat-3), glycogen Synthase Kinase (GSK)-3β and nuclear factor (NF)-κB. Alpelisib also impaired APAP-instigated immune cell infiltration in the liver via reducing systemic granulocyte/macrophage-colony stimulating factor (GM-CSF) release and reversed APAP-induced abnormalities in the systemic and hepatic levels of the anti-inflammatory IL-10 and IL-22. In conclusion, selective modulation of the PI3Kα activity by alpelisib can hinder the inflammatory response and infiltration of immune cells occurring by APAP-hepatotoxicity.

Emerging roles of tyrosine kinases in hepatic inflammatory diseases and therapeutic opportunities

Inflammation has been convicted of causing and worsening many liver diseases like acute liver failure, fibrosis, cirrhosis, fatty liver and liver cancer. Pattern recognition receptors (PRRs) like TLRs 4 and 9 localized on resident or recruited immune cells are well known cellular detectors of pathogen and damage-associated molecular patterns (PAMPs/DAMPs). Stimulation of these receptors generates the sterile and non-sterile inflammatory responses in the liver. When these responses are repeated, there will be a sustained liver injury that may progress to fibrosis and its outcomes. Crosstalk between inflammatory/fibrogenic-dependent streams and certain tyrosine kinases (TKs) has recently evolved in the context of hepatic diseases. Because of TKs increasing importance, their role should be elucidated to highlight effective approaches to manage the diverse liver disorders. This review will give a brief overview of types and functions of some TKs like BTK, JAKs, Syk, PI3K, Src and c-Abl, as well as receptors for TAM, PDGF, EGF, VEGF and HGF. It will then move to discuss the roles of these TKs in the regulation of the proinflammatory, fibrogenic and tumorigenic responses in the liver. Lastly, the therapeutic opportunities for targeting TKs in hepatic inflammatory disorders will be addressed. Overall, this review sheds light on the diverse TKs that have substantial roles in hepatic disorders and potential therapeutics modulating their activity.

The anticancer and EGFR-TK/CDK-9 dual inhibitory potentials of new synthetic pyranopyrazole and pyrazolone derivatives: X-ray crystallography, in vitro, and in silico mechanistic investigations

Treatment options for the management of breast cancer are still inadequate. This inadequacy is attributed to the lack of effective targeted medications, often resulting in the recurrence of metastatic disorders. Cumulative evidence suggests that epidermal growth factor receptor (EGFR-TK) and cyclin-dependent kinases-9 (CDK-9) overexpression correlates with worse overall survival in breast cancer patients. Pyranopyrazole and pyrazolone are privileged options for the development of anticancer agents. Inspired by this proven scientific fact, we report here the synthesis of two new series of suggested anticancer molecules incorporating both heterocycles together with their characterization by IR, 1H NMR, 13C NMR, 13C NMR-DEPT, and X-ray diffraction methods. An attempt to get the pyranopyrazole-gold complexes was conducted but unexpectedly yielded benzylidene-2,4-dihydro-3H-pyrazol-3-one instead. This unexpected result was confirmed by X-ray crystallographic analysis. All newly synthesized compounds were assessed for their anti-proliferative activity against two different human breast cancer cells, and the obtained results were compared with the reference drug Staurosporine. The target compounds revealed variable cytotoxicity with IC50 at a low micromolar range with superior selectivity indices. Target enzyme EGFR-TK and CDK-9 assays showed that compounds 22 and 23 effectively inhibited both biological targets with IC50 values of 0.143 and 0.121 µM, respectively. Molecular docking experiments and molecular dynamics simulation were also conducted to further rationalize the in vitro obtained results.Communicated by Ramaswamy H. Sarma.

New Sulfamethoxazole Derivatives as Selective Carbonic Anhydrase IX and XII Inhibitors: Design, Synthesis, Cytotoxic Activity and Molecular Modeling

In this study new sulphamethoxazole derivatives (S1-S4, S6-S12, and S14-S22) were designed and synthesized and their structures were fully characterized and validated using NMR, mass, and IR spectroscopy, as well as elemental analyses. All new derivatives (S1-S22) were assayed against human carbonic anhydrase (hCAs IX and XII) for their inhibitory activities. hCAs IX and XII were chosen due to the fact that CAIX expression is recognized as a hypoxia marker with a poor prognosis in breast cancer. When compared to Dorzolamide HCl as a standard reference, derivatives S2, S3, S8, S9, and S15 had the most effective inhibition with low IC₅₀ values. The active compounds were further evaluated against hCAs I and II inhibitory activity and compounds S8, S9 and S15 showed the least inhibitory effect compared to the reference standard, acetazolamide, indicating that their effect in normal cells is the lowest. Cell viability tests for the selected compounds were carried out on MCF7 (normoxia and hypoxia) and on the normal breast cell line (MCF10a) with Staurosporine as a standard. The results showed that compound S15 had a highly potent cytotoxic effect. Furthermore, cell cycle analysis results showed that compound S15 triggered cell cycle arrest and apoptosis in G1/S of MCF7 cancer cells. Finally, molecular docking was performed to point out the possible explanation for the vital structural features and key-interactions exerted by our ligands with hCAs IX and XII that might share additional designs and highlight possible leads for a hopeful anticancer agent. Consequently, sulphamethoxazole Derivative S15 could be the potential lead for emerging selective cytotoxic compounds directing h CAs IX and XII.

The contribution of sterile inflammation to the fatty liver disease and the potential therapies

Hepatic inflammation is prevalent in several metabolic liver diseases. Recent scientific advances about the pathogenesis of metabolic liver diseases showed an emerging role of several damage-associated molecular patterns (DAMPs), including DNA, high-mobility group box 1 (HMGB1), ATP and uric acid. For these DAMPs to induce inflammation, they should stimulate pattern recognition receptors (PRRs), which are located in the hepatic immune cells like resident Kupffer cells, infiltrated neutrophils, monocytes or dendritic cells. As a consequence, proinflammatory cytokines like interleukins (ILs)-1β and 18 alongside tumor necrosis factor (TNF)-α are overproduced and released, leading to pronounced hepatic inflammation and cellular death. This review highlights the contribution of these DAMPs and PRRs in the settings of alcoholic and nonalcoholic steatohepatitis. The review also summarizes the therapeutic usefulness of targeting NLR family pyrin domain containing 3 (NLRP3)-inflammasome, Toll-like receptors (TLRs) 4 and 9, IL-1 receptor (IL-1R), caspase 1, uric acid and GMP-AMP synthase/stimulator of interferon genes (cGAS/STING) in these hepatic inflammatory disorders.

Design, synthesis, and biological evaluation of novel pyrido-dipyrimidines as dual topoisomerase II/FLT3 inhibitors in leukemia cells

Dual inhibition of topoisomerase (topo) II and FLT3 kinase, as in the case of C-1311, was shown to overcome the shortcomings of using topo II inhibitors solely. In the present study, we designed and synthesized two series of pyrido-dipyrimidine- and pseudo-pyrido-acridone-containing compounds. The two series were evaluated against topo II and FLT3 as well as the HL-60 promyelocytic leukemia cell line in vitro. Compounds 6, 7, and 20 showed higher potency against topo II than the standard amsacrine (AMSA), whereas compounds 19 and 20 were stronger FLT3 inhibitors than the standard DACA. Compounds 19 and 20 showed to be dual inhibitors of both enzymes. Compounds 6, 7, 19, and 20 were more potent inhibitors of the HL-60 cell line than the standard AMSA. The results of the in vitro DNA flow cytometry analysis assay and Annexin V-FITC apoptosis analysis showed that 19 and 20 induced cell cycle arrest at the G2/M phase, significantly higher total percentage of apoptosis, and late-stage apoptosis in HL-60 cell lines than AMSA. Furthermore, 19 and 20 upregulated several apoptosis biomarkers such as p53, TNFα, caspase 3/7 and increased the Bax/Bcl-2 ratio. These results showed that 19 and 20 deserve further evaluation of their antiproliferative activities, particularly in leukemia. Molecular docking studies were performed for selected compounds against topo II and FLT3 enzymes to investigate their binding patterns. Compound 19 exerted dual fitting inside the active site of both enzymes.

Digoxin mitigates diethylnitrosamine-induced acute liver injury in mice via limiting production of inflammatory mediators

The cardiotonic digoxin has been recently shown to possess an anti-inflammatory potential in numerous metabolic and inflammatory disorders. However, data about digoxin’s impact in the setting of acute liver injury and sterile inflammation are still limited. Here, we investigated the potential effect of digoxin pretreatments (0.25 and 0.5 mg/kg, oral) on the severity of acute hepatotoxicity in mice challenged with a single dose of diethylnitrosamine (DN; 150 mg/kg, intraperitoneal) for 24 h. Our results indicated that digoxin pretreatments dose-dependently mitigated DN-induced rise of hepatocellular injury parameters and necroinflammation scores. Digoxin, particularly at dose of 0.5 mg/kg, boosted the number of PCNA positive hepatocytes, leading to improvement of the reparative potential in hepatocytes of DN-intoxicated livers. Digoxin’s ameliorative effect on DN-hepatotoxicity coincided with (i) lowering the increased hepatic production and release of the proinflammatory mediators IL-17A, IL-1β and TNF-α, and (ii) impeding the attraction and infiltration of monocytes to the liver, as denoted by decreasing serum MCP-1 and F4/80 immunohistochemical expression. These effects were attributed to reducing DN-induced activation of NF-κB and overexpression of CD98 in the liver. Meanwhile, DN elicited a decline in the hepatic production and release of the anti-inflammatory cytokines IL-22 and IL-6, which was intensified by digoxin, especially at a dose 0.5 mg/kg. In conclusion, digoxin conferred liver protection against DN-insult by impairing the overproduction of proinflammatory cytokines and infiltration of inflammatory cells to the liver.

The JAK inhibitor ruxolitinib abrogates immune hepatitis instigated by concanavalin A in mice

Therapeutics that impair the innate immune responses of the liver during the inflammatory cytokine storm like that occurring in COVID-19 are greatly needed. Much interest is currently directed toward Janus kinase (JAK) inhibitors as potential candidates to mitigate this life-threatening complication. Accordingly, this study investigated the influence of the novel JAK inhibitor ruxolitinib (RXB) on concanavalin A (Con A)-induced hepatitis and systemic hyperinflammation in mice to simulate the context occurring in COVID-19 patients. Mice were orally treated with RXB (75 and 150 mg/kg) 2 h prior to the intravenous administration of Con A (20 mg/kg) for a period of 12 h. The results showed that RXB pretreatments were efficient in abrogating Con A-instigated hepatocellular injury (ALT, AST, LDH), necrosis (histopathology), apoptosis (cleaved caspase-3) and nuclear proliferation due to damage (PCNA). The protective mechanism of RXB were attributed to i) prevention of Con A-enhanced hepatic production and systemic release of the proinflammatory cytokines TNF-α, IFN-γ and IL-17A, which coincided with decreasing infiltration of immune cells (monocytes, neutrophils), ii) reducing Con A-induced hepatic overexpression of IL-1β and CD98 alongside NF-κB activation, and iii) lessening Con A-induced consumption of GSH and GSH peroxidase and generation of oxidative stress products (MDA, 4-HNE, NOx) in the liver. In summary, JAK inhibition by RXB led to eminent protection of the liver against Con A-deleterious manifestations primarily via curbing the inflammatory cytokine storm driven by TNF-α, IFN-γ and IL-17A.

Ingestion of mannose ameliorates thioacetamide-induced intrahepatic oxidative stress, inflammation and fibrosis in rats

BACKGROUND AND AIMS

The monosaccharide mannose has gained recent interest for its beneficial effect against certain inflammatory disorders. Nevertheless, the influence of mannose on experimentally-induced liver fibrosis and the ensued inflammation is still not fully clear to date.

MAIN METHODS

The current study investigated the outcomes of treating rats with mannose (0.2 ml of 20% w/v, oral gavage) 30 min before the twice weekly intoxication with thioacetamide (TAA) (200 mg/kg, intraperitoneal) for a total period of 8 weeks.

KEY FINDINGS

The data indicated that mannose markedly dampened TAA-induced liver fibrosis, as indicated by lowering the fibrotic bridges shown by Masson's trichrome staining. This effect was consistent with reducing TAA-induced hepatocellular injury, as evidenced biochemically (serum ALT and AST activities) and pathologically (necroinflammation score). These hepatoprotective effects mediated by mannose were attributed to i) reversing TAA-induced rise in malondialdehyde (MDA) and decrease in reduced glutathione (GSH) expressions in the liver, ii) limiting TAA-induced release of the proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), iii) impairing TAA-induced activation of hepatic stellate cells by downregulating α-smooth muscle actin expression (α-SMA), and more importantly, iv) dampening TAA-induced fibrogenesis driven by transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF).

SIGNIFICANCE

Mannose may be a valuable candidate for preventing oxidative stress, inflammation and fibrogenesis in the liver.

A New CDK2 Inhibitor with 3-Hydrazonoindolin-2-One Scaffold Endowed with Anti-Breast Cancer Activity: Design, Synthesis, Biological Evaluation, and In Silico Insights

Background: Cyclin-dependent kinases (CDKs) regulate mammalian cell cycle progression and RNA transcription. Based on the structural analysis of previously reported CDK2 inhibitors, a new compound with 3-hydrazonoindolin-2-one scaffold (HI 5) was well designed, synthesized, and biologically evaluated as a promising anti-breast cancer hit compound. Methods: The potential anti-cancerous effect of HI 5 was evaluated using cytotoxicity assay, flow cytometric analysis of apoptosis and cell cycle distribution, ELISA immunoassay, in vitro CDK2/cyclin A2 activity, and molecular operating environment (MOE) virtual docking studies. Results: The results revealed that HI 5 exhibits pronounced CDK2 inhibitory activity and cytotoxicity in human breast cancer MCF-7 cell line. The cytotoxicity of HI 5 was found to be intrinsically mediated apoptosis, which in turn, is associated with low Bcl-2 expression and high activation of caspase 3 and p53. Besides, HI 5 blocked the proliferation of the MCF-7 cell line and arrested the cell cycle at the G2/M phase. The docking studies did not confirm which one of geometric isomers (syn and anti) is responsible for binding affinity and intrinsic activity of HI 5. However, the molecular dynamic studies have confirmed that the syn-isomer has more favorable binding interaction and thus is responsible for CDK2 inhibitory activity. Discussion: These findings displayed a substantial basis of synthesizing further derivatives based on the 3-hydrazonoindolin-2-one scaffold for favorable targeting of breast cancer.

Inhibition of Bruton tyrosine kinase by acalabrutinib dampens lipopolysaccharide/galactosamine-induced hepatic damage

Bruton tyrosine kinase (BTK) sits at the crossroads of adaptive and innate immunities. Nevertheless, the detailed role of BTK activation in hepatic inflammatory disorders is still elusive to date. Accordingly, we investigated the impact of blocking BTK activation by acalabrutinib (ACB) on lipopolysaccharide/galactosamine (LPS/D-GaIN)-induced deleterious manifestations in the liver. This was achieved by pretreating mice with ACB (6, 12 or 24 mg/kg, oral) 2 h before challenge with LPS/D-GaIN (70 μg/kg and 700 mg/kg, respectively, i.p.) for 6 h. The results showed that ACB (6 and 12 mg/kg) (i) curbed LPS/D-GaIN-induced rise in biochemical (serum ALT, AST and LDH) and histological (necrosis, degeneration and congestion scores) indices of hepatocellular injury; (ii) attenuated LPS/D-GaIN-induced elevation in parameters of hepatocellular apoptosis (cleaved caspase 3) and proliferation (PCNA); and (iii) importantly, mitigated LPS/D-GaIN-induced recruitment and infiltration of the inflammatory cells to the liver evidenced by lowering elevated serum MCP-1 concentration and hepatic F4/80 immunostaining. These effects were linked to ACB dose-dependent inhibition of NF-κB nuclear translocation that subsequently reduced LPS/D-GaIN-mediated release of TNF-α, IL-1β and IL-22 in the blood circulation. However, a dose of 12 mg/kg of ACB elevated the hepatic TNF-α, IL-1β and IL-22 concentrations that arose from a compensatory activation of ERK and JNK. Inhibition of BTK also attenuated LPS/D-GaIN-induced overexpression of CD98, which is another contributor alongside cytokines for monocyte recruitment. Therapeutically, targeting BTK by ACB is an efficient approach for hitting multiple points with one agent that can dampen hepatocellular injury, death, immune cell recruitment and inflammation cascade.

The c-Met inhibitor capmatinib alleviates acetaminophen-induced hepatotoxicity

Acetaminophen (APAP)-induced hepatotoxicity comes among the most frequent humans' toxicities caused by drugs. So far, therapeutic interventions for such type of drug-induced toxicity are still limited. In the current study, we examined the influence of capmatinib (Cap), a novel c-Met inhibitor, on APAP-induced hepatotoxicity in mice when administered 2 h prior, 2 h post and 4 h post APAP-challenge. The results revealed that Cap administration significantly attenuated APAP-induced liver injury when administered only 2 h prior and post APAP-administration. Cap hepatoprotective effect was mediated by lowering the excessive formation of lipid peroxidation and nitrosative stress products caused by APAP. Besides, Cap attenuated APAP-induced overproduction and release of proinflammatory mediators like TNF-α, IL-1β, IL-17A, IL-6, and MCP-1. Cap treatment also led to avoidance of APAP-subsequent repair by abating APAP-induced elevation of hepatic IL-22 and PCNA expressions. In conclusion, c-Met receptor inhibition may be a potential strategy for alleviating APAP-hepatotoxicity, especially when administered in the early phase of intoxication.

Impact of interferon β-1b, interferon β-1a and fingolimod therapies on serum interleukins-22, 32α and 34 concentrations in patients with relapsing-remitting multiple sclerosis

Interleukins (ILs)-22, 32α and 34 were monitored in the sera of relapsing-remitting multiple sclerosis (RRMS) patients at different time intervals with or without interferon β-1b, interferon β-1a and fingolimod treatments. The results showed that sera of untreated RRMS patients were statistically higher in concentration of IL-22 (P < .001), but not IL-32α and IL-34, than those of healthy individuals. Interestingly, interferon β-1b, interferon β-1a and fingolimod treatments led to a significant decrease of serum concentrations of ILs-22 and 32α, but not 34, at 6 and 12 months of treatment, compared to their initial concentrations before initiating therapy. The correlation analysis revealed that the changes of serum IL-22 (r = 0.814) and, to a lesser extent, IL-32α (r = 0.381) concentrations were positively correlated with those of expanded disability status score. In conclusion, serum IL-22 concentration may be a potential marker for MS disease severity and efficacy of treatment.

Repression of acetaminophen-induced hepatotoxicity by a combination of celastrol and brilliant blue G

The sterile inflammatory response is an eminent contributor to acetaminophen (APAP)-hepatotoxicity in humans. Recent advances unraveled an axial role of the NLRP3-inflammasome in APAP-post injury inflammation. Nevertheless, the role of signaling events preceded the NLRP3-inflammasome activation, like the transcription factor NF-κB and the purinergic receptor P2X7, is still unclear and needs further elucidation. Here, we investigated the pharmacological inhibition of these upstream signaling molecules by celastrol and brilliant blue G (BBG) (separately or simultaneously) in APAP-hepatotoxicity in mice. The results indicated that both celastrol and BBG pretreatments, especially when combined together, curbed APAP-induced hepatocellular injury (ALT, AST and LDH) and death (necrosis and apoptosis). The underlying mechanisms of protection of such combination against APAP-challenge were attributed to their efficient cooperation in: i) preventing the consumption of hepatic antioxidants (reduced glutathione and superoxide dismutase); ii) limiting the overproduction of lipid peroxidation aldehydes (malondialdehyde and 4-hydroxynonenal) and total nitrate/nitrite products; iii) attenuating the inflammatory cells accumulation in the liver, as evidenced by reducing the number of F4/80 positive cells/field in immunostaining and myeloperoxidase activity; iv) reversing the dysregulation in production of pro-inflammatory (TNF-α, IL-17A and IL-23) and anti-inflammatory (IL-10) cytokines; and v) enhancing the reparative capacity of injured hepatocytes, as demonstrated by increasing the percentage of PCNA positive hepatocytes per field of immunostaining. In conclusion, this murine study elicits a potential clinical applicability and therapeutic utility of celastrol and BBG combination in human cases of APAP-overdose hepatotoxicity.

Inhibition of the JAK/STAT pathway by ruxolitinib ameliorates thioacetamide-induced hepatotoxicity

In an attempt to explore the role of the JAK/STAT pathway in liver inflammation, we investigated the effect of intervening this pathway by ruxolitinib in thioacetamide (TAA)-induced hepatotoxicity. Ruxolitinib treatments were administered to male mice either before or after intoxication with TAA. The hepatic histopathological and serum biochemical assessment revealed that ruxolitinib pre-treatments dose-dependently reduced TAA-induced liver injury, caspase 3 cleavage and increase in number of hepatocytes positive for the pro-apoptotic Bax, as well as inflammatory cells positive for F4/80 and myeloperoxidase activity in the liver. Ruxolitinib pre-treatments also curbed TAA-induced rise in NF-κB nuclear expression and STAT3 phosphorylation. Ruxolitinib pre-treatments also lowered TAA-induced elevation of hepatic oxidative stress parameters (total nitrate/nitrite and 4-hydroxynonenal), but did not restore the hepatic antioxidant reduced glutathione. Interestingly, ruxolitinib, especially at a dose of 200 mg/kg, dampened the overproduction of pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ, IL-23 and IL-17A), which coincided with boosting the release of the anti-inflammatory cytokine IL-10. Ruxolitinib when used as a post-treatment (1 and 3 h after TAA-insult) could still spare the liver from injury and might be clinically applicable. In conclusion, the multimechanistic-hepatoprotective activity of ruxolitinib can be linked to its ameliorative properties on cellular death, oxidative stress and inflammation machinery.

The SMAC mimetic BV6 induces cell death and sensitizes different cell lines to TNF-α and TRAIL-induced apoptosis

The inhibitors of apoptosis proteins are implicated in promoting cancer cells survival and resistance toward immune surveillance and chemotherapy. Second mitochondria-derived activator of caspases (SMAC) mimetics are novel compounds developed to mimic the inhibitory effect of the endogenous SMAC/DIABLO on these IAPs. Here, we examined the potential effects of the novel SMAC mimetic BV6 on different human cancer cell lines. Our results indicated that BV6 was able to induce cell death in different human cancer cell lines. Mechanistically, BV6 dose dependently induced degradation of IAPs, including cIAP1 and cIAP2. This was coincided with activating the non-canonical NF -kappa B (NF-κB) pathway, as indicated by stabilizing NF-κB-inducing kinase (NIK) for p100 processing to p52. More interestingly, BV6 was able to sensitize some of the resistant cancer cell lines to apoptosis induced by the death ligands tumor necrosis factor-α (TNF-α) and TNF-related apoptosis-inducing ligand (TRAIL) that are produced by different cells of the immune system. Such cell death enhancement was mediated by inducing an additional cleavage of caspase-9 to augment that of caspase-8 induced by death ligands. This eventually led to more processing of the executioner caspase-3 and poly (ADP-ribose) polymerase (PARP). In conclusion, therapeutic targeting of IAPs by BV6 might be an effective approach to enhance cancer regression induced by immune system. Our data also open up the future possibility of using BV6 in combination with other antitumor therapies to overcome cancer drug resistance.

The novel TLR9 antagonist COV08-0064 protects from ischemia/reperfusion injury in non-steatotic and steatotic mice livers

Ischemia/reperfusion (I/R) injury constitutes a major reason for failure of liver surgeries and transplantation. I/R injury is more severe in steatotic livers and limits their use in transplantation. Here, we present a novel and selective Toll-like receptor 9 (TLR9) antagonist COV08-0064 and test its potential to protect from I/R-induced injury in normal and steatotic livers. The in vivo effects of COV08-0064 pretreatment were investigated on normal chow diet (NCD) and high fat diet (HFD)-fed mice subjected to segmental (70%) warm hepatic I/R. Also, the in vitro effects of COV08-0064 were elucidated in murine macrophages and dendritic cells. Mice on a HFD had pronouncedly greater hepatic I/R injury than mice on a NCD. COV08-0064-pretreatment to both NCD and HFD-fed mice reduced hepatic I/R injury. COV08-0064-pretreatment was associated with less production of the liver inflammatory cytokines and mediators TNF-α, IL-1β, IL-6, NLRP3, iNOS and MCP-1. These manifestations were preceded with inhibition of JNK and ERK phosphorylation and TLR9 cleavage in the liver. COV08-0064 enhanced the hepatic expression of the endogenous anti-inflammatory cytokines IL-10 and IL-1Ra at the early phase I/R injury. In vitro, COV08-0064 selectively blocked mRNA upregulation of TNF-α, IL-1β, NLRP3 and MCP-1 in macrophages and IFN-β mRNA in dendritic cells induced by the TLR9 agonist CpG-ODN. These effects were concordant with inhibition of JNK, ERK, IκBα and IKKα/β phosphorylation. In conclusion, TLR9 signaling inhibition by COV08-0064 may be an effective approach in liver surgeries including transplantation to limit I/R-injury and overcome the shortages in the donor pool by incorporating steatotic livers.

Polymorphisms of glutathione S-transferase π 1 and toll-like receptors 2 and 9: Association with breast cancer susceptibility

Polymorphisms in antioxidant enzymes and innate immune receptors have been implicated in the development of various types of cancer. The present study aimed to investigate whether polymorphisms of glutathione S-transferase π 1 (GSTP1) and toll-like receptors (TLRs) 2 and 9 are associated with susceptibility to breast cancer among females. The study was conducted on 72 Egyptian female patients with breast cancer, along with 100 healthy volunteers. Polymorphisms of GSTP1 (codon 105 Ile/Val) and TLR9 rs187084 (1237T/C) genes were assessed by polymerase chain reaction (PCR)-restriction fragment length polymorphism, while the -196 to -174 deletion/insertion (del/ins) polymorphism of TLR2 was detected by PCR. The results indicated a decrease in GSTP1 Val allele frequency in breast cancer patients compared with healthy controls, at rates of 22.9 vs. 32.5%, respectively. In addition, the breast cancer group demonstrated a decreased TLR9 C allele frequency compared with the control group, at rates of 36.1 vs. 51.5%, respectively (P=0.0047). A non-significant difference was detected in the frequency of the TLR2 -196 to -174 del allele in breast cancer patients when compared to normal controls. In conclusion, these results suggested that the GSTP1 Val and TLR9 1237C alleles, but not TLR2 -196 to -174 del, are likely to be associated with breast cancer development among females.

Synthesis and Biological Evaluation of New N-(4-Substituted phenyl)glycine Derivatives as Potential Anti-inflammatory Agents

BACKGROUND

Designing new anti-inflammatory agents possessing safe therapeutic profiles and devoid of potential undesirable side effects is an active field in medicinal chemistry. Thus, a series of N-(4-substituted phenyl)glycine derivatives was designed and synthesized. The idea behind the design is to utilize the bifunctionality of 4-aminoacetophenone via converting the amino group into glycine derivative as a side arm to mimic the glycine amino acid enhancing the overall physicochemical and biological characteristics. In addition, the opposite acetyl group was used as a center for modification and derivatization.

METHODS

The starting N-(4-acetylphenyl)glycine was converted into two intermediates: the chalcone analog 2 and the thiosemicarbazone derivative 8. Both 2 and 8 were derivatized and/or cyclized into different heterocyclic target derivatives (3-7 and 9-12). The target compounds were screened for anti-inflammatory activity using carrageenan-induced rat paw edema assay.

RESULTS

The results showed that compounds 6, 7, and 3, were the most active among the tested compounds at 50 mg/kg dose level with % inhibition of edema of 51.82, 43.80, and 40.39, respectively.

CONCLUSION

The authors succeeded to introduce a simple and versatile skeleton with a side arm resembling the glycine amino acid; imparting a potential improvement in physicochemical properties. We utilize the other side of the skeleton’s aromatic ring as a center for derivatization. The chalcone analog and its cyclized heterocyclic derivatives were of remarkably higher anti-inflammatory activity than the thiosemicarbazone and its derivatives.

Therapeutic Opportunities in Damage-Associated Molecular Pattern-Driven Metabolic Diseases

SIGNIFICANCE

Sterile inflammation is a common finding present in various metabolic disorders. This type of inflammation is mediated by damage-associated molecular patterns (DAMPs) that are released upon cellular injury to activate pattern recognition receptors on innate immune cells and amplify organ damage.

RECENT ADVANCES

In the last decade, DAMPs, such as high-mobility group protein B1, nucleic acids (DNA, RNA), adenosine triphosphate, and other metabolites, were found to contribute to the inflammatory response in diabetes, gout, obesity, steatohepatitis, and atherosclerosis. Varied receptors, including Toll-like receptors (TLRs), the purinergic P2X(7) receptors, and nucleotide-binding domain, and leucine-rich repeat protein 3 (NLRP3)-inflammasome sense DAMPs and DAMP-like molecules and release the proinflammatory cytokines, interleukin (IL)-1β and IL-18.

CRITICAL ISSUES

Available therapeutic approaches that interfered with the signaling of TLRs, P2X(7), NLRP3-inflammasome, and IL-1β showed encouraging results in metabolic diseases, which will be also highlighted in this review.

FUTURE DIRECTIONS

It is important to understand the origination of DAMPs and how they contribute to the inflammatory response in metabolic disorders to develop selective and efficient therapeutics for intervention.

The novel Janus kinase inhibitor ruxolitinib confers protection against carbon tetrachloride-induced hepatotoxicity via multiple mechanisms

Therapeutic targeting of the JAK/STAT pathway, the principal signaling mechanism for numerous cytokines, might be an effective approach for limiting inflammation in different organs, including the liver. Therefore, we investigated whether targeting this pathway by the novel JAK inhibitor ruxolitinib could mitigate hepatic damage provoked by carbon tetrachloride (CCl4). Male mice received ruxolitinib treatments (75 and 150 mg/kg, oral) 2 h prior to intoxication with CCl4 (10 ml/kg of 0.3% v/v CCl4 solution in olive oil, intraperitoneal) for 24 h. Our results showed that ruxolitinib treatments dose-dependently alleviated CCl4-induced hepatic injury and necroinflammation, as indicated by biochemical markers of injury and histopathology. We unraveled also the mechanisms involved in these hepatoprotective effects. These comprise (i) reducing infiltration of neutrophils and macrophages, as demonstrated by reducing myeloperoxidase activity and F4/80 positive macrophages; (ii) abating apoptosis of hepatocytes, as denoted by decreasing hepatocytes positive for Bax protein; (iii) inhibiting elevation of TNF-α, IL-1β and IL-10; (iv) inhibiting NF-κB activation and translocation to the nucleus, as visualized immunohistochemically; (v) attenuating activation of the IL-23/IL-17 pathway via targeting IL-17, but not IL-23; (vi) antagonizing hepatic oxidative stress by increasing the antioxidant levels (reduced glutathione, glutathione-S-transferase and superoxide dismutase) and decreasing products of lipid peroxidation (malondialdehyde and 4-hydroxynonenal) and total nitrate/nitrite; and (vii) more interestingly, modulating hepatocyte regeneration according to the extent of damage, as quantified by PCNA-immunohistochemistry. In conclusion, our study sheds light on the therapeutic usefulness and the potential underlying mechanisms of the novel JAK inhibitor ruxolitinib in hepatic inflammatory disorders.

Celastrol ameliorates murine colitis via modulating oxidative stress, inflammatory cytokines and intestinal homeostasis

Therapeutic agents that block the nuclear factor-kappa B (NF-κB) pathway might be beneficial for incurable inflammatory diseases, such as ulcerative colitis. Here, we investigated the effect of the novel NF-κB inhibitor celastrol on murine colitis. Colitis was induced in male mice by administration of 5% (w/v) dextran sulfate sodium (DSS) in drinking water for a period of 5 days, followed by a 2 day recovery period. Celastrol (2mg/kg, oral) was administered daily over the 1 week of the study. Our results indicated that treatment with celastrol attenuated DSS-induced colon shortening and neutrophil infiltration. Besides, celastrol ameliorated DSS-induced colon injury and inflammatory signs as visualized by histopathology. The mechanisms behind these beneficial effects of celastrol were also elucidated. These include (i) counteracting DSS-induced oxidative stress in the colon via decreasing lipid peroxidation products (malondialdehyde and 4-hydroxynonenal) and increasing the antioxidant levels (reduced glutathione, glutathione-S-transferase and superoxide dismutase); (ii) inhibiting DSS-induced activation of the NLRP3-inflammasome, as evidenced by decreased production of IL-1β and IFN-γ as indirect measure of IL-18 in the colon; (iii) targeting DSS-induced activation of the IL-23/IL-17 pathway by abating the elevation of IL-23 and IL-17A levels in the colon; (iv) augmenting the anti-inflammatory defense mechanisms via increasing IL-10 and TNF-α levels in the colon; (v) and more importantly, maintaining intestinal epithelial reconstitution and homeostasis via attenuating the overexpression of CD98 in colonic epithelial cells. In conclusion, our study provides novel insights into the beneficial effects of celastrol as a promising candidate for the treatment of ulcerative colitis in humans.

Comparison of early treatment with low doses of nilotinib, imatinib and a clinically relevant dose of silymarin in thioacetamide-induced liver fibrosis

Our previous study has already confirmed a promising anti-fibrotic activity especially for nilotinib; when given at a daily dose of 10 mg/kg during the last 4 weeks of thioacetamide (TAA)-induced liver fibrosis for 12 weeks in rats. Therefore, this study was carried out to compare the prophylactic potential of low dose of nilotinib to that of its predecessor, imatinib, and a clinically relevant dose of the standard hepatoprotective treatment, silymarin, in TAA-intoxication. Male Wistar rats received intraperitoneal injections of TAA (150 mg/kg, twice weekly) for 8 weeks, as well as oral treatments with imatinib (5 mg/kg/day), nilotinib (5 mg/kg/day) and silymarin (50 mg/kg/day) from the first day of TAA-intoxication. At the end of the study, chronic hepatic injury was evaluated by analysis of liver function tests in serum. Hepatic oxidative stress was assessed by measuring malondialdehyde, 4-hydroxynonenal, total nitrate/nitrite and reduced glutathione contents, as well as myeloperoxidase and superoxide dismutase activities. Hepatic fibrosis was evaluated by histopathology and collagen content. Our results suggest that the prophylactic potential of nilotinib (5 mg/kg/day), imatinib (5mg/kg/day) and silymarin (50 mg/kg/day) in TAA-intoxication for 8 weeks is lower than the late treatments of nilotinib (10 mg/kg/day), imatinib (10mg/kg/day) and silymarin (100 mg/kg/day) during the last 4 weeks of TAA-intoxication for 12 weeks in rats. Taken together, this study suggests that nilotinib may have higher anti-fibrotic activity when administered at a significant stage of fibrosis as a result of impairment of its metabolism in the fibrotic livers.

Nilotinib counteracts thioacetamide-induced hepatic oxidative stress and attenuates liver fibrosis progression

The aim of this study was to evaluate and compare the effects of imatinib and nilotinib to that of silymarin on established liver fibrosis and oxidative stress in a thioacetamide (TAA) rat model. Male Wistar rats received intraperitoneal (i.p.) injections of TAA (150mg/kg, twice weekly) for 12weeks. Daily treatments with imatinib (10mg/kg), nilotinib (10mg/kg), and silymarin (100mg/kg) were administered orally during the last 4weeks of TAA-administration. At the end of the study, hepatic damage was evaluated by analysis of liver function tests in serum. Hepatic histopathology and collagen content were employed to quantify liver fibrosis. Hepatic oxidative stress was assessed by measuring malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), total nitrate/nitrite (NOx), and reduced glutathione (GSH) contents, as well as myeloperoxidase (MPO) and superoxide dismutase (SOD) activities. Nilotinib, silymarin and, to a lesser extent, imatinib treatments ameliorated TAA-induced hepatic oxidative stress and damage as indicated by hepatic MDA, 4-HNE, NOx, GSH, MPO and SOD levels, as well as liver function tests. Hepatic histopathology results revealed that nilotinib, imatinib, and silymarin treatments decreased the mean score of fibrosis in TAA-treated rats by 24, 14, and 3%, respectively. However, nilotinib and silymarin, but not imatinib, treatments decreased hepatic collagen content in TAA-treated rats by 17 and 36%, respectively. In conclusion, we demonstrated for the first time that nilotinib not only protected against hepatic oxidative stress, but also slowed down liver fibrosis progression. Thus, we provide the first evidence that nilotinib might be a promising anti-fibrotic drug.

Comparison of imatinib, nilotinib and silymarin in the treatment of carbon tetrachloride-induced hepatic oxidative stress, injury and fibrosis

Effective and well-tolerated anti-fibrotic drugs are currently lacking. Therefore, this study was carried out to investigate the potential anti-fibrotic effects of imatinib, nilotinib and silymarin on established hepatic fibrosis in the carbon tetrachloride (CCl(4)) rat model. Male Wistar rats received intraperitoneal injections of CCl(4) twice weekly for 8weeks, as well as daily intraperitoneal treatments of imatinib (10 and 20mg/kg), nilotinib (10 and 20mg/kg) and silymarin (100mg/kg) during the last 4weeks of CCl(4)-intoxication. At the end of the study, hepatic damage was evaluated by analysis of liver function tests and hepatic oxidative stress parameters. Hepatic fibrosis was evaluated by histopathology and morphometry, as well as collagen and 4-hydroxyproline contents. Nilotinib (20mg/kg) was the most effective treatment to counteract CCl(4)-induced hepatic injury as indicated by liver function tests and histopathology. Nilotinib (10mg/kg), nilotinib (20mg/kg) and silymarin (100mg/kg) treatments reduced the mean score of hepatic fibrosis by 31%, 68% and 47%, respectively, and hepatic collagen content by 47%, 49% and 18%, respectively in CCl(4)-treated rats. Hepatic morphometric evaluation and 4-hydroxyproline content revealed that CCl(4)-induced fibrosis was ameliorated significantly by nilotinib (20mg/kg) and imatinib (20mg/kg). Unlike nilotinib, imatinib (20mg/kg) showed some sort of hepatic injury evidenced by elevation of serum aminotransferases and total bilirubin levels, and hepatic total nitrate/nitrite content, as well as characteristic anisonucleosis visualized with the hematoxylin-eosin staining. In conclusion, this study provides the evidence that nilotinib exerts anti-fibrotic activity and suggests that it may be valuable in the treatment of hepatic fibrosis in humans.