Methyl palmitate: inhibitor of phagocytosis in primary rat Kupffer cells

Exploring and Analyzing the Systemic Delivery Barriers for Nanoparticles

Most nanomedicines require efficient in vivo delivery to elicit diagnostic and therapeutic effects. However, en route to their intended tissues, systemically administered nanoparticles often encounter delivery barriers. To describe these barriers, we propose the term "nanoparticle blood removal pathways" (NBRP), which summarizes the interactions between nanoparticles and the body's various cell-dependent and cell-independent blood clearance mechanisms. We reviewed nanoparticle design and biological modulation strategies to mitigate nanoparticle-NBRP interactions. As these interactions affect nanoparticle delivery, we studied the preclinical literature from 2011-2021 and analyzed nanoparticle blood circulation and organ biodistribution data. Our findings revealed that nanoparticle surface chemistry affected the in vivo behavior more than other nanoparticle design parameters. Combinatory biological-PEG surface modification improved the blood area under the curve by ~418%, with a decrease in liver accumulation of up to 47%. A greater understanding of nanoparticle-NBRP interactions and associated delivery trends will provide new nanoparticle design and biological modulation strategies for safer, more effective, and more efficient nanomedicines.

Lack of Nck1 protein and Nck-CD3 interaction caused the increment of lipid content in Jurkat T cells

Background

The non-catalytic region of tyrosine kinase (Nck) is an adaptor protein, which is ubiquitously expressed in many types of cells. In T cells, the Nck1 isoform promotes T cell receptor signalling as well as actin polymerisation. However, the role of Nck1 in the lipid metabolism in T cells is unknown. In the present study, we investigated the effect of the Nck1 protein and Nck–CD3 interaction on lipid metabolism and on the physical and biological properties of Jurkat T cells, using a newly developed holotomographic microscope.

Results

Holotomographic microscopy showed that Nck1-knocked-out cells had membrane blebs and were irregular in shape compared to the rounded control cells. The cell size and volume of Nck1-deficient cells were comparable to those of the control cells. Nck1-knocked-out Jurkat T cells had a greater lipid content, lipid mass/cell mass ratio, and lipid metabolite levels than the control cells. Interestingly, treatment with a small molecule, AX-024, which inhibited Nck–CD3 interaction, also caused an increase in the lipid content in wild-type Jurkat T cells, as found in Nck1-deficient cells.

Conclusions

Knockout of Nck1 protein and hindrance of the Nck–CD3 interaction cause the elevation of lipid content in Jurkat T cells.

Identification of Bioactive Pentacyclic Triterpenoids and Fatty Acid Derivatives from Cissus quadrangularis and C. rotundifolia Through Untargeted Metabolite Profiling

Comparative metabolite profiling of crude extracts of leaf and stem of two medicinally important species of genus Cissus was performed. Gas Chromatography - Mass Spectrometry (GC-MS/MS) of methanoloic extracts of leaf and stem of Cissus rotundifolia revealed the presence of around 30 compounds, out of which 15 were identified through NIST14 library based on their mass spectral pattern. Some of the important metabolites included betulinaldehyde, methyl palmitate, β-amyrin acetate, 2-naphthol, 2-phenylethanol and myristic acid. Among these metabolites, betulinaldehyde was the most abundant compound with 36.44% relative abundance. In contrast, 36 compounds were detected in the aqueous and methanolic extracts of C. quadrangularis stem, out of which 21 compounds were identified through NIST14 library. Saturated fatty acids and ascorbic acid derivatives constitute the major fraction with 44.30% and 36.40% of the total peak area. In addition to these, coumaran, quinoline and trans-phytol were also identified in the extracts of C. quadrangularis. The comparative metabolite profiling showed higher percentage of betulinaldehyde (~ 36%) and lauric acid (19.42%) in C. rotundifolia while that of methyl palmitate (~ 0.76%) and coumaran (1.48%) in C. qudrangularis. Cissus species are medicinally known for their bone healing properties and the metabolic profiling of these herbs will further be utilised for identification and characterization of the novel bioactive compounds responsible for various medicinal properties.

Nanoparticle based medicines: approaches for evading and manipulating the mononuclear phagocyte system and potential for clinical translation

For decades, nanomedicines have been reported as a potential means to overcome the limitations of conventional drug delivery systems by reducing side effects, toxicity and the non-ideal pharmacokinetic behaviour typically exhibited by small molecule drugs. However, upon administration many nanoparticles prompt induction of host inflammatory responses due to recognition and uptake by macrophages, eliminating up to 95% of the administered dose. While significant advances in nanoparticle engineering and consequent therapeutic efficacy have been made, it is becoming clear that nanoparticle recognition by the mononuclear phagocyte system (MPS) poses an impassable junction in the current framework of nanoparticle development. Hence, this has negative consequences on the clinical translation of nanotechnology with respect to therapeutic efficacy, systemic toxicity and economic benefit. In order to improve the translation of nanomedicines from bench-to-bedside, there is a requirement to either modify nanomedicines in terms of how they interact with intrinsic processes in the body, or modulate the body to be more accommodating for nanomedicine treatments. Here we provide an overview of the current standard for design elements of nanoparticles, as well as factors to consider when producing nanomedicines that have minimal MPS-nanoparticle interactions; we explore this landscape across the cellular to tissue and organ levels. Further, rather than designing materials to suit the body, a growing research niche involves modulating biological responses to administered nanomaterials. We here discuss how developing strategic methods of MPS 'pre-conditioning' with small molecule or biological drugs, as well as implementing strategic dosing regimens, such as 'decoy' nanoparticles, is essential to increasing nanoparticle therapeutic efficacy. By adopting such a perspective, we hope to highlight the increasing trends in research dedicated to improving nanomedicine translation, and subsequently making a positive clinical impact.

Palmitic Acid Methyl Ester Enhances Adipogenic Differentiation in Rat Adipose Tissue-Derived Mesenchymal Stem Cells through a G Protein-Coupled Receptor-Mediated Pathway

Adipogenic differentiation from stem cells has become a research target due to the increasing interest in obesity. It has been indicated that adipocytes can secrete palmitic acid methyl ester (PAME), which is able to regulate stem cell proliferation. However, the effects of PAME on adipogenic differentiation in stem cell remain unclear. Here, we present that the adipogenic differentiation medium supplemented with PAME induced the differentiation of rat adipose tissue-derived mesenchymal stem cells (rAD-MSCs) into adipocyte. rAD-MSCs were treated with PAME for 12 days and then subjected to various analyses. The results from the present study show that PAME significantly increased the levels of adipogenic differentiation markers, PPARγ and Gpd1, and enhanced adipogenic differentiation in rAD-MSCs. Furthermore, the level of GPR40/120 protein increased during induction of adipocyte differentiation in rAD-MSCs. Cotreatment with PAME and a GPR40/120 antagonist together inhibited the PAME-enhanced adipogenic differentiation. Moreover, PAME significantly increased phosphorylation of extracellular signal-regulated kinases (ERK), but not AKT and mTOR. Cotreatment with PAME and a GPR40/120 antagonist together inhibited the PAME-enhanced ERK phosphorylation and adipogenic differentiation. PAME also increased the intracellular Ca²⁺ levels. Cotreatment with PAME and a Ca²⁺ chelator or a phospholipase C (PLC) inhibitor prevented the PAME-enhanced ERK phosphorylation and adipogenic differentiation. Our data suggest that PAME activated the GPR40/120/PLC-mediated pathway, which in turn increased the intracellular Ca²⁺ levels, thereby activating the ERK, and eventually enhanced adipogenic differentiation in rAD-MSCs. The findings from the present study might help get insight into the physiological roles and molecular mechanism of PAME in regulating stem cell differentiation.

Boosting nanomedicine performance by conditioning macrophages with methyl palmitate nanoparticles

Surface PEGylation, biological camouflage, shape and stiffness modulation of nanoparticles as well as liver blockade and macrophage depletion have all improved the blood longevity of nanomedicines. Yet, the mononuclear phagocytic system still recognizes, sequesters, and processes the majority of blood borne particles. Here, the natural fatty acid methyl palmitate is combined with endogenous blood components - albumin - realizing ∼200 nm stable, spherical nanoparticles (MPN) capable of inducing a transient and reversible state of dormancy into macrophages. In primary bone marrow derived monocytes (BMDM), the rate of internalization of 5 different particles, ranging in size from 200 up to 2000 nm, with spherical and discoidal shapes, and made out of lipids and polymers, was almost totally inhibited after an overnight pre-treatment with 0.5 mM MPN. Microscopy analyses revealed that MPN reversibly reduced the extension and branching complexity of the microtubule network in BMDM, thus altering membrane bulging and motility. In immunocompetent mice, a 4 h pre-treatment with MPN was sufficient to redirect 2000 nm rigid particles from the liver to the lungs realizing a lung-to-liver accumulation ratio larger than 2. Also, in mice bearing U87-MG tumor masses, a 4 h pre-treatment with MPN enhanced the therapeutic efficacy of docetaxel-loaded nanoparticles significantly inhibiting tumor growth. The natural liver sequestering function was fully recovered overnight. This data would suggest that MPN pre-treatment could transiently and reversibly inhibit non-specific particle sequestration, thus redirecting nanomedicines towards their specific target tissue while boosting their anti-cancer efficacy and imaging capacity.

'Methyl palmitate attenuates adjuvant induced arthritis in rats by decrease of CD68 synovial macrophages

The study was designed to investigate the potential anti-arthritic effects of methyl palmitate in an adjuvant arthritis model in rats that shares many histopathological similarities with human RA. The underlying mechanism and its effect on CD68 macrophages were investigated, as a further argument to its possible efficacy in RA treatment. A normal control group was injected only with saline, arthritic group, and three treatment groups with CFA induced arthritis received methyl palmitate (MP) at three different doses (75, 150, 300 mg/kg/week for 3 weeks, intraperitoneal). The degree of ipsilateral paw swelling, ankle diameter, spleen index, thymus index and the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β were measured. In addition, the underlying molecular mechanism was investigated using CD68 expression. Methyl palpitate significantly and dose dependently decreased the arthritic symptoms as measured by ipsilateral paw volume and ankle diameter. It showed no effect on body weight but significantly decreased splenic, thymus index, serum TNF-α and IL-1β. CD68 macrophages expression and the overall synovial inflammatory cellularity were halted. Methyl palmitate exhibits significant anti-inflammatory and exerts a potential anti-arthritic effect in a rat model of adjuvant induced arthritis. Furthermore, it inhibits expression of synovial CD68 macrophage that validate its therapeutic potential adjuvant arthritis.

Methyl Palmitate-A suitable adjuvant for Sorafenib therapy to reduce in vivo toxicity and to enhance anti-cancer effects on hepatocellular carcinoma cells

This study focused on evaluating the potency of Methyl Palmitate in reducing in vivo toxicity with enhancement of anti-cancer effects of Sorafenib. In vitro anti-cancer effects on human Hep-G2 cell line were analysed by MTT, Trypan blue, clonogenic, wound scratch migration and TUNEL assays. An in vivo study for anti-angiogenesis effect, toxicity and teratogenicity was analysed in Zebrafish embryos. The combination of Sorafenib (4.5 µmol/L) with Methyl Palmitate (3 mmol/L) significantly enhanced anti-cancer effects on Hep-G2 cell line by increasing cytotoxicity (P ≤ .05 in MTT assay; P ≤ .01 in Trypan blue assay), apoptosis (P ≤ .05) and decreasing the metastatic migration (P ≤ .01) than Sorafenib alone treatment. A prominent inhibition of angiogenesis in vivo was observed for combination treatment. At 5 dpf, only <20% toxicity was observed for 3 mmol/L Methyl palmitate while it was 65.75% for Sorafenib treatment which implies that it is a safer dose for in vivo treatments. A highly significant (P ≤ .001) reduction (43.20%) in toxicity was observed in combination treatment. Thus, the Sorafenib-Methyl Palmitate combination showed a promising treatment effect with significantly reduced in vivo toxicity when compared with Sorafenib alone treatment, and hence the Methyl Palmitate may serve as a good adjuvant for Sorafenib therapy.

In Vitro and In Vivo Screening of Wild Bitter Melon Leaf for Anti-Inflammatory Activity against Cutibacterium acnes

Cutibacterium acnes (formerly Propionibacterium acnes) is a key pathogen involved in the development and progression of acne inflammation. The numerous bioactive properties of wild bitter melon (WBM) leaf extract and their medicinal applications have been recognized for many years. In this study, we examined the suppressive effect of a methanolic extract (ME) of WBM leaf and fractionated components thereof on live C. acnes-induced in vitro and in vivo inflammation. Following methanol extraction of WBM leaves, we confirmed anti-inflammatory properties of ME in C. acnes-treated human THP-1 monocyte and mouse ear edema models. Using a bioassay-monitored isolation approach and a combination of liquid–liquid extraction and column chromatography, the ME was then separated into n-hexane, ethyl acetate, n-butanol and water-soluble fractions. The hexane fraction exerted the most potent anti-inflammatory effect, suppressing C. acnes-induced interleukin-8 (IL-8) production by 36%. The ethanol-soluble fraction (ESF), which was separated from the n-hexane fraction, significantly inhibited C. acnes-induced activation of mitogen-activated protein kinase (MAPK)-mediated cellular IL-8 production. Similarly, the ESF protected against C. acnes-stimulated mouse ear swelling, as measured by ear thickness (20%) and biopsy weight (23%). Twenty-four compounds in the ESF were identified using gas chromatograph–mass spectrum (GC/MS) analysis. Using co-cultures of C. acnes and THP-1 cells, β-ionone, a compound of the ESF, reduced the production of IL-1β and IL-8 up to 40% and 18%, respectively. β-ionone also reduced epidermal microabscess, neutrophilic infiltration and IL-1β expression in mouse ear. We also found evidence of the presence of anti-inflammatory substances in an unfractionated phenolic extract of WBM leaf, and demonstrated that the ESF is a potential anti-inflammatory agent for modulating in vitro and in vivo C. acnes-induced inflammatory responses.

M3, a 1,4-Dihydropyridine Derivative and Mixed L-/T-Type Calcium Channel Blocker, Attenuates Isoproterenol-Induced Toxicity in Male Wistar Rats

Recent evidence indicates that Ca²⁺ dysregulation is involved in the pathogenesis of isoproterenol (ISP)-induced biochemical toxicity and associated oxidative stress. In this study, we investigated the chemopreventive benefit of M3, a 1,4-dihydropyridine calcium channel blocker, against ISP-induced toxicity in male Wistar rats. Adult rats were divided into eight groups of six rats/group. Groups 1-5 received normal saline (control, 10 mL/kg/day, p.o.), ISP (85 mg/kg/day, s.c.), M3 lower dose (M3LD, 5 mg/kg, p.o.), M3 upper dose (M3UD, 20 mg/kg/day, p.o.), and Nifedipine (NFD, 20 mg/kg/day, p.o.), respectively. Others (groups 6-8) were pretreated with either M3LD, M3UD or NFD one hour before ISP administration. All rats were sacrificed 24 h after the last administration and changes in biochemical, hematological, and antioxidant parameters were assessed. Histologic examination of the heart, liver and kidney was also conducted. ISP elevated (p < 0.05) Ca²⁺, alanine aminotransferase, lactate dehydrogenase, triglycerides, and low-density lipoprotein levels when compared with control. Similarly, ISP increased levels of markers of renal function (p < 0.01), C-reactive protein (148.1%) and myocardial malondialdehyde (MDA, 88.7%) and tumor necrosis factor-alpha (109.2%). Platelet level was reduced (p < 0.05) in the ISP-intoxicated control rats. M3 exhibited antioxidant property, reduced levels of triglycerides, MDA and improved biochemical and hematological alterations associated with ISP toxicity. M3, however, was not effective in restoring histological changes that characterized ISP toxicity at the doses used. M3 offers chemopreventive benefits against ISP toxicity possibly through L-/T-type calcium channels blockade and modulatory actions on biochemical and antioxidant homeostasis.

Probiotic treatment induced change of inflammation related metabolites in IBS-D patients/double-blind, randomized, placebo-controlled trial

There have been many studies suggesting that probiotics are effective in patients with diarrhea-predominant irritable bowel syndrome (IBS-D). However, its mechanism of action as well as prediction of response is still to be elucidated. In the present study, to find out metabolomic characteristics of probiotic effect in IBS-D, we compared IBS symptom changes and metabolomic characteristics in the subjects' urine samples between multi-strain probiotics (one strain of Lactobacillus sp. and four strains of Bifidobacterium sp.) group (n = 32) and placebo group (n = 31). After 8 weeks' administration (3 times/day), dissatisfaction in bowel habits and stool frequencies were significantly improved. Also, probiotics group had significantly changed seven metabolites including palmitic acid methyl ester (PAME) and 4,6-dihydroxyquinoline, 4-(2-aminophenyl)-2,4-dioxobutanoic acid (DOBA). According to IBS-SSS and IBS-QoL questionnaires, IBS-SSS responders showed higher PAME levels and IBS-QoL responders showed lower DOBA levels. This suggests potential role of these metabolites as a biomarker to predict probiotics effect in IBS-D patients.

Palmitic Acid Methyl Ester Induces G2/M Arrest in Human Bone Marrow-Derived Mesenchymal Stem Cells via the p53/p21 Pathway

Bone marrow-derived mesenchymal cells (BM-MSCs) are able to differentiate into adipocytes, which can secrete adipokines to affect BM-MSC proliferation and differentiation. Recent evidences indicated that adipocytes can secrete fatty acid metabolites, such as palmitic acid methyl ester (PAME), which is able to cause vasorelaxation and exerts anti-inflammatory effects. However, effects of PAME on BM-MSC proliferation remain unclear. The aim of this study was to investigate the effect of PAME on human BM-MSC (hBM-MSC) proliferation and its underlying molecular mechanisms. hBM-MSCs were treated with PAME for 48 h and then subjected to various analyses. The results from the present study show that PAME significantly reduced the levels of G₂/M phase regulatory proteins, cyclin-dependent kinase 1 (Cdk1), and cyclin B1 and inhibited proliferation in hBM-MSCs. Moreover, the level of Mdm2 protein decreased, while the levels of p21 and p53 protein increased in the PAME-treated hBM-MSCs. However, PAME treatment did not significantly affect apoptosis/necrosis, ROS generation, and the level of Cdc25C protein. PAME also induced intracellular acidosis and increased intracellular Ca²⁺ levels. Cotreatment with PAME and Na⁺/H⁺ exchanger inhibitors together further reduced the intracellular pH but did not affect the PAME-induced decreases of cell proliferation and increases of the cell population at the G₂/M phase. Cotreatment with PAME and a calcium chelator together inhibited the PAME-increased intracellular Ca²⁺ levels but did not affect the PAME-induced cell proliferation inhibition and G₂/M cell cycle arrest. Moreover, the half-life of p53 protein was prolonged in the PAME-treated hBM-MSCs. Taken together, these results suggest that PAME induced p53 stabilization, which in turn increased the levels of p53/p21 proteins and decreased the levels of Cdk1/cyclin B1 proteins, thereby preventing the activation of Cdk1, and eventually caused cell cycle arrest at the G₂/M phase. The findings from the present study might help get insight into the physiological roles of PAME in regulating hBM-MSC proliferation.

Ethanol Exposure Impairs AMPK Signaling and Phagocytosis in Human Alveolar Macrophages: Role of Ethanol Metabolism

BACKGROUND

Chronic alcohol consumption impairs alveolar macrophage's (AM) function and increases risk for developing lung infection and pneumonia. However, the mechanism and metabolic basis of alcohol-induced AM dysfunction leading to lung infection are not well defined, but may include altered ethanol (EtOH) and reactive oxygen species metabolism and cellular energetics. Therefore, oxidative stress, endoplasmic reticulum (ER) stress, the formation of fatty acid ethyl esters [FAEEs, nonoxidative metabolites of EtOH], AMP-activated protein kinase (AMPK) signaling, and phagocytic function were examined in freshly isolated AM incubated with EtOH.

METHODS

AMs separated from bronchoalveolar lavage fluid samples obtained from normal volunteers were incubated with EtOH for 24 hours. AMPK signaling and ER stress were assessed using Western blotting, FAEEs by GC-MS, oxidative stress by immunofluorescence using antibodies to 4-hydroxynonenal, and phagocytosis by latex beads. Oxidative stress was also measured in EtOH-treated AMs with/without AMPK activator [5-aminoimidazole-4-carboxamide ribonucleotide (AICAR)] or inhibitor (Compound C), and in AMs incubated with FAEEs. mRNA expression for interleukins (IL-6 and IL-8), monocyte chemoattractant protein (MCP)-1, and transforming growth factor (TGF)-β was measured in AM treated with EtOH or FAEEs using RT-PCR.

RESULTS

EtOH exposure to AM increased oxidative stress, ER stress, and synthesis of FAEEs, decreased phosphorylated AMPK, and impaired phagocytosis. Attenuation or exacerbation of EtOH-induced oxidative stress by AICAR or Compound C, respectively, suggests a link between AMPK signaling, EtOH metabolism, and related oxidative stress. The formation of FAEEs may contribute to EtOH-induced oxidative stress as FAEEs also produced concentration-dependent oxidative stress. An increased mRNA expression of IL-6, IL-8, and MCP-1 by FAEEs is key finding to suggest a metabolic basis of EtOH-induced inflammatory response.

CONCLUSIONS

EtOH-induced impaired phagocytosis, oxidative stress, ER stress, and dysregulated AMPK signaling are plausibly associated with the formation of FAEEs and may participate in the pathogenesis of nonspecific pulmonary inflammation.

Potential premalignant status of gastric portion excluded after Roux en-Y gastric bypass in obese women: A pilot study

We evaluated whether the excluded stomach (ES) after Roux-en-Y gastric bypass (RYGB) can represent a premalignant environment. Twenty obese women were prospectively submitted to double-balloon enteroscopy (DBE) with gastric juice and biopsy collection, before and 3 months after RYGB. We then evaluated morphological and molecular changes by combining endoscopic and histopathological analyses with an integrated untargeted metabolomics and transcriptomics multiplatform. Preoperatively, 16 women already presented with gastric histopathological alterations and an increased pH (≥4.0). These gastric abnormalities worsened after RYGB. A 90-fold increase in the concentration of bile acids was found in ES fluid, which also contained other metabolites commonly found in the intestinal environment, urine, and faeces. In addition, 135 genes were differentially expressed in ES tissue. Combined analysis of metabolic and gene expression data suggested that RYGB promoted activation of biological processes involved in local inflammation, bacteria overgrowth, and cell proliferation sustained by genes involved in carcinogenesis. Accumulated fluid in the ES appears to behave as a potential premalignant environment due to worsening inflammation and changing gene expression patterns that are favorable to the development of cancer. Considering that ES may remain for the rest of the patient’s life, long-term ES monitoring is therefore recommended for patients undergoing RYGB.

Acridocarpus Smeathmannii (DC.) Guill. & Perr. Root enhanced reproductive behavior and sexual function in male wistar rats: Biochemical and pharmacological mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Novel therapeutic opportunities from medicinal agents continue to arouse scientific interest in recent times. Still, there is a dearth of information as regards experimental evidence generated from medicinal plants that would yield pharmacological agents for the treatment of erectile dysfunction. Acridocarpus Smeathmannii (DC.) Guill. & Perr. Root (ASR) has a long history as an aphrodisiac in African traditional medicine. Thus, this study investigated the reproductive potentials and associated biochemical mechanisms of its hydroethanolic extract (HEASR) in male Wistar rats. Also, the bioactive compounds were identified.

MATERIALS AND METHODS

Fifty-four male albino rats (180 ± 20 g) were divided into nine groups of six rats/group. Control, group 1 received normal saline (10 mL/kg). Groups 2-6 rats were administered sildenafil (1.43 mg/kg/day), mesterolone (0.36 mg/kg/day), doxazocin (0.03 mg/kg/day), HEASR1 (50 mg/kg/day) and HEASR2 (200 mg/kg/day) respectively. Others received co-administration of HEASR2 with standard drugs. Treatment lasted for 28 days via oral gavage.

RESULTS

An acute oral toxicity of HEASR up to 2 g/kg produced no mortality in mice p.o. while the median lethal dose was estimated to be 810 mg/kg i.p. HEASR2 administration or in combination with sildenafil, mesterolone and doxazocin increased mounting frequencies on day 28 by 77.44%, 122.65%, 148.5% and 93.88% and sperm counts by 38.29%, 55.21%, 42.48%, and 48.98% respectively in treated rats. HEASR2 + sildenafil elevated testosterone and follicle stimulating hormone levels by 36.33% and 24.55% while HEASR2 + doxazocin elevated luteinizing hormone levels by 97.44% in rats. HEASR modulated prostate-specific antigen and malondialdehyde levels respectively. Reduced glutathione, superoxide dismutase, and catalase activities were raised in five selected organs. Serum nitric oxide but not cyclooxygenase-2 or tumor necrosis factor-α levels was moderately improved in rats.

CONCLUSION

Overall, the results obtained demonstrated the potential of HEASR as a male reproductive enhancer, thus justify its folklore applications. Further, octadecanoic acid ethyl ester was the most abundant bioactive component present.

Administration of methyl palmitate prevents non-alcoholic steatohepatitis (NASH) by induction of PPAR-α

BACKGROUND AND AIMS

The lack of valid therapeutic approach that can ameliorate the manifestations of NASH is a barrier to therapeutic development. Therefore, we investigate the novel role of Methyl Palmitate (MP) in preventing NASH and the possible mechanism involved.

METHODS

50 Male C57BL/6 J mice were randomly divided into 5 groups (n = 10). The control group was fed control diet; model group was fed MCD diet; MP 1 group was fed MCD diet supplemented with MP (75 mg/kg/day); MP 2 group was fed MCD plus MP diet (150 mg/kg/day); and MP 3 group was fed MCD plus MP diet (300 mg/kg/day). Histological staining's, and commercially available kits for serum ALT and AST and hepatic contents of TG, TC, MDA, SOD, and GSH were used to assess NASH. Furthermore, relative liver protein and gene expression levels were determined by Western Blot and qPCR, respectively.

RESULTS

Mice fed MCD diet developed NASH, which was markedly improved by MP in a dose-dependent manner. MP treatment improved hepatic content of TG, TC, MDA, SOD and GSH and serum levels of ALT and AST. In vivo studies showed that MP treatment activated PPARα expression, that in turns, promoted β-oxidation protein and gene expressions, suppressed TNFα, MCP1, TGFβ1 and Colla1 protein and gene expression levels, contributing to the prevention of NASH.

CONCLUSIONS

Our results indicated that MP could successfully prevent NASH. This effect of MP was mediated through induction of PPARα pathway. This study provides a novel therapeutic target that plays pivotal role in the prevention of NASH.

Palmitic Acid Methyl Ester and Its Relation to Control of Tone of Human Visceral Arteries and Rat Aortas by Perivascular Adipose Tissue

Background: Perivascular adipose tissue (PVAT) exerts anti-contractile effects on visceral arteries by release of various perivascular relaxing factors (PVRFs) and opening voltage-gated K⁺ (K_v) channels in vascular smooth muscle cells (VSMCs). Palmitic acid methyl ester (PAME) has been proposed as transferable PVRF in rat aorta. Here, we studied PVAT regulation of arterial tone of human mesenteric arteries and clarified the contribution of K_v channels and PAME in the effects.

Methods: Wire myography was used to measure vasocontractions of mesenteric artery rings from patients undergoing abdominal surgery. Isolated aortic rings from Sprague-Dawley rats were studied for comparison. PVAT was either left intact or removed from the arterial rings. Vasocontractions were induced by external high K⁺ (60 mM), serotonin (5-HT) or phenylephrine. PAME (10 nM−3 μM) was used as vasodilator. K_v channels were blocked by XE991, a K_v7 (KCNQ) channel inhibitor, or by 4-aminopyridine, a non-specific K_v channel inhibitor. PAME was measured in bathing solutions incubated with rat peri-aortic or human visceral adipose tissue.

Results: We found that PVAT displayed anti-contractile effects in both human mesenteric arteries and rat aortas. The anti-contractile effects were inhibited by XE991 (30 μM). PAME (EC₅₀ ~1.4 μM) was capable to produce relaxations of PVAT-removed rat aortas. These effects were abolished by XE991 (30 μM), but not 4-aminopyridine (2 mM) or NDGA (10 μM), a lipoxygenases inhibitor. The cytochrome P450 epoxygenase inhibitor 17-octadecynoic acid (ODYA 10 μM) and the soluble epoxide hydrolase inhibitor 12-(3-adamantan-1-ylureido)-dodecanoic acid (AUDA 10 μM) slightly decreased PAME relaxations. PAME up to 10 μM failed to induce relaxations of PVAT-removed human mesenteric arteries. 5-HT induced endogenous PAME release from rat peri-aortic adipose tissue, but not from human visceral adipose tissue.

Conclusions: Our data also suggest that K_v7 channels are involved in the anti-contractile effects of PVAT on arterial tone in both rat aorta and human mesenteric arteries. PAME could contribute to PVAT relaxations by activating K_v7 channels in rat aorta, but not in human mesenteric arteries.

Effect of removing Kupffer cells on nanoparticle tumor delivery

A recent metaanalysis shows that 0.7% of nanoparticles are delivered to solid tumors. This low delivery efficiency has major implications in the translation of cancer nanomedicines, as most of the nanomedicines are sequestered by nontumor cells. To improve the delivery efficiency, there is a need to investigate the quantitative contribution of each organ in blocking the transport of nanoparticles to solid tumors. Here, we hypothesize that the removal of the liver macrophages, cells that have been reported to take up the largest amount of circulating nanoparticles, would lead to a significant increase in the nanoparticle delivery efficiency to solid tumors. We were surprised to discover that the maximum achievable delivery efficiency was only 2%. In our analysis, there was a clear correlation between particle design, chemical composition, macrophage depletion, tumor pathophysiology, and tumor delivery efficiency. In many cases, we observed an 18-150 times greater delivery efficiency, but we were not able to achieve a delivery efficiency higher than 2%. The results suggest the need to look deeper at other organs such as the spleen, lymph nodes, and tumor in mediating the delivery process. Systematically mapping the contribution of each organ quantitatively will allow us to pinpoint the cause of the low tumor delivery efficiency. This, in effect, enables the generation of a rational strategy to improve the delivery efficiency of nanoparticles to solid tumors either through the engineering of multifunctional nanosystems or through manipulation of biological barriers.

Characterization of a Bvg-regulated fatty acid methyl-transferase in Bordetella pertussis

The whooping cough agent Bordetella pertussis controls the expression of its large virulence regulon in a coordinated manner through the two-component signal transduction system BvgAS. In addition to the genes coding for bona fide virulence factors, the Bvg regulon comprises genes of unknown function. In this work, we characterized a new Bvg-activated gene called BP2936. Homologs of BP2936 are found in other pathogenic Bordetellae and in several other species, including plant pathogens and environmental bacteria. We showed that the gene product of BP2936 is a membrane-associated methyl-transferase of free fatty acids. We thus propose to name it FmtB, for fatty acid methyl-transferase of Bordetella. The role of this protein was tested in cellular and animal models of infection, but the loss of BP2936 did not appear to affect host-pathogen interactions in those assays. The high level of conservation of BP2936 among B. pertussis isolates nevertheless argues that it probably plays a role in the life cycle of this pathogen.

Isolation and Culture of Single Cell Types from Rat Liver

There have been few reports on the simultaneous isolation of multiple liver cell populations thus far. As such, this study was aimed at establishing a protocol for the simultaneous separation of hepatocytes (HCs), hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs) and Kupffer cells (KCs) from the rat liver and assessing the in vitro culture of these cells. Single-cell suspensions from the liver were obtained by ethylene glycol tetraacetic acid/collagenase perfusion. After low-speed centrifugal separation of HCs, pronase was added to the nonparenchymal cell fraction to eliminate the remaining HCs. Subsequently, HSCs, LSECs and KCs were purified by two steps of density gradient centrifugation using Nycodenz and Percoll in addition to selective attachment. Pronase treatment increased the HSC yield (1.5 ± 0.2 vs. 0.7 ± 0.3 cells/g liver, p < 0.05) and improved LSEC purity (93.6 ± 3.6 vs. 82.5 ± 5.6%, p < 0.01). The isolated cells could also be cultured in vitro. LSEC apoptosis began on day 3 and reached a maximum on day 7. A few surviving LSECs began proliferating and split to form a cobblestone, sheet-like appearance on day 14. The LSECs on day 14 lost fenestrations but retained scavenger function. Thus, viable and purified liver cells were obtained with a high yield from the rat liver using the developed method, which may be useful for studying the physiology and pathology of the liver in the future.

Cytoprotective potential of tiron and methyl palmitate against acetaminophen-induced acute liver injury

Acute liver injury is a debilitating disorder associated with loss of synthetic and detoxifying functions of the liver. This investigation was designed to assess cytoprotective efficacy of daily oral tiron (300 mg/kg) and daily oral methyl palmitate (300 mg/kg) against acetaminophen-induced acute liver injury. Rats were orally pretreated with either tiron or methyl palmitate at doses (300 mg/kg) for 7 days prior to oral acetaminophen (3 g/kg). Biochemical assay of markers of hepatotoxicity indices and oxidative stress was undertaken. Expression of inflammatory cytokine IL-6 was also evaluated. Histopathological examination of liver specimens was carried out as well. Both methyl palmitate and tiron significantly reversed the acetaminophen-induced elevation of biochemical markers (ALT, AST, and ALP) with restoration of SOD levels. Serum albumin levels and GSH liver contents increased, but in a nonsignificant manner. Moreover, methyl palmitate and tiron significantly decreased the level of serum LDH and serum IL-6 levels. Histopathology revealed that tiron markedly reduced the extent of acetaminophen-induced necrosis and methyl palmitate moderately decreased the necrosis in liver tissue. Methyl palmitate (300 mg/kg) and tiron (300 mg/kg) demonstrated promising hepatoprotective effects against acetaminophen-induced acute liver injury via modulation of inflammatory response and alleviation of the oxidative stress, allowing the preservation of hepatic functions.

Sundew plant, a potential source of anti-inflammatory agents, selectively induces G2/M arrest and apoptosis in MCF-7 cells through upregulation of p53 and Bax/Bcl-2 ratio

The worldwide cancer incidences are remarkable despite the advancement in cancer drug discovery field, highlighting the need for new therapies focusing on cancer cell and its microenvironment, including inflammation. Several species of Drosera (family: Droseraceae) are used in various traditional as well as homeopathic systems of medicine. Drosera burmannii Vahl. is also enlisted in French Pharmacopoeia in 1965 for the treatment of inflammatory diseases, including chronic bronchitis, asthma and whooping cough. The present study is designed to substantiate the potential of D. burmannii in in vitro anticancer activity and its relation with anti-inflammatory property. In vitro anticancer study revealed that DBME is inhibiting the proliferation of MCF-7 cells without affecting the viability of other malignant and non-malignant cells. DBME induced G2/M phase arrest and apoptosis in MCF-7 cells by suppressing the expression of cyclin A1, cyclin B1 and Cdk-1 and increasing the expression of p53, Bax/Bcl-2 ratio leading to activation of caspases and PARP degradation. Presence of caspase-8 (Z-IETD-fmk) and caspase-9 (Z-LEHD-fmk) inhibitors alone did prevent the apoptosis partially while apoptosis prevention was significantly observed when used in combination, suggesting vital role of caspases in DBME-induced apoptosis in MCF-7 cells. DBME also downregulated LPS-induced increased expression of iNOS, COX-2 and TNF-α along with suppression on intracellular ROS production that confirms the potential of DBME as anti-inflammatory extract. GCMS analysis revealed the presence of four major compounds hexadecanoic acid, tetradecanoic acid, hexadecen-1-ol, trans-9 and 1-tetradecanol along with some other fatty acid derivatives and carotenoids (Beta-doradecin) in DBME. These findings confirmed the anti-inflammatory activity of DBME, which is already listed in French Pharmacopeia in 1965. Here we have additionally reported the anti-breast cancer activity of DBME and its relation to the anti-inflammatory potential. Hence, an ethnopharmacological approach can be considered as useful tool for the discovery of new drug leads.

Lung gene therapy-How to capture illumination from the light already present in the tunnel

Gene therapy has been considered as the most ideal medical intervention for genetic diseases because it is intended to target the cause of diseases instead of disease symptoms. Availability of techniques for identification of genetic mutations and for in vitro manipulation of genes makes it practical and attractive. After the initial hype in 1990s and later disappointments in clinical trials for more than a decade, light has finally come into the tunnel in recent years, especially in the field of eye gene therapy where it has taken big strides. Clinical trials in gene therapy for retinal degenerative diseases such as Leber's congenital amaurosis (LCA) and choroideremia demonstrated clear therapeutic efficacies without apparent side effects. Although these successful examples are still rare and sporadic in the field, they provide the proof of concept for harnessing the power of gene therapy to treat genetic diseases and to modernize our medication. In addition, those success stories illuminate the path for the development of gene therapy treating other genetic diseases. Because of the differences in target organs and cells, distinct barriers to gene delivery exist in gene therapy for each genetic disease. It is not feasible for authors to review the current development in the entire field. Thus, in this article, we will focus on what we can learn from the current success in gene therapy for retinal degenerative diseases to speed up the gene therapy development for lung diseases, such as cystic fibrosis.

Methanol Extract of Artemisia apiacea Hance Attenuates the Expression of Inflammatory Mediators via NF- κ B Inactivation

Artemisia apiacea Hance is one of the most widely used herbs for the treatment of malaria, jaundice, and dyspeptic complaint in oriental medicine. This study investigated the effects of methanol extracts of A. apiacea Hance (MEAH) on the induction of inducible nitric oxide synthase (iNOS) and proinflammatory mediators by lipopolysaccharide (LPS) in Raw264.7 macrophage cells and also evaluated the in vivo effect of MEAH on carrageenan-induced paw edema in rats. MEAH treatment in Raw264.7 cells significantly decreased LPS-inducible nitric oxide production and the expression of iNOS in a concentration-dependent manner, while MEAH (up to 100 μg/mL) had no cytotoxic activity. Results from immunoblot analyses and ELISA revealed that MEAH significantly inhibited the expression of cyclooxygenase-2, tumor necrosis factor-α, interleukin-1β, and interleukin-6 in LPS-activated cells. As a plausible molecular mechanism, increased degradation and phosphorylation of inhibitory-κBα and nuclear factor-κB accumulation in the nucleus by LPS were partly blocked by MEAH treatment. Finally, MEAH treatment decreased the carrageenan-induced formation of paw edema and infiltration of inflammatory cells in rats. These results demonstrate that MEAH has an anti-inflammatory therapeutic potential that may result from the inhibition of nuclear factor-κB activation, subsequently decreasing the expression of proinflammatory mediators.

Technologies for investigating the physiological barriers to efficient lipid nanoparticle-siRNA delivery

Small interfering RNA (siRNA) therapeutics have advanced from bench to clinical trials in recent years, along with new tools developed to enable detection of siRNA delivered at the organ, cell, and subcellular levels. Preclinical models of siRNA delivery have benefitted from methodologies such as stem-loop quantitative polymerase chain reaction, histological in situ immunofluorescent staining, endosomal escape assay, and RNA-induced silencing complex loading assay. These technologies have accelerated the detection and optimization of siRNA platforms to overcome the challenges associated with delivering therapeutic oligonucleotides to the cytosol of specific target cells. This review focuses on the methodologies and their application in the biodistribution of siRNA delivered by lipid nanoparticles.

Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models

Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). MP and EP decreased NF-κB expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models.

Insights antifibrotic mechanism of methyl palmitate: impact on nuclear factor kappa B and proinflammatory cytokines

Fibrosis accompanies most chronic liver disorders and is a major factor contributing to hepatic failure. Therefore, the need for an effective treatment is evident. The present study was designed to assess the potential antifibrotic effect of MP and whether MP can attenuate the severity of oxidative stress and inflammatory response in chronic liver injury. Male albino rats were treated with either CCl(4) (1 ml/kg, twice a week) and/or MP (300 mg/kg, three times a week) for six weeks. CCl(4)-intoxication significantly increased liver weight, serum aminotransferases, total cholesterol and triglycerides while decreased albumin level and these effects were prevented by co-treatment with MP. As indicators of oxidative stress, CCl(4)-intoxication caused significant glutathione depletion and lipid peroxidation while MP co-treatment preserved them within normal values. As markers of fibrosis, hydroxyproline content and α-SMA expression increased markedly in the CCl(4) group and MP prevented these alterations. Histopathological examination by both light and electron microscope further confirmed the protective efficacy of MP. To elucidate the antifibrotic mechanisms of MP, the expression of NF-κB, iNOS and COX-2 and the tissue levels of TNF-α and nitric oxide were assessed; CCl(4) increased the expression of NF-κB and all downstream inflammatory cascade while MP co-treatment inhibited them. Collectively these findings indicate that MP possesses a potent antifibrotic effect which may be partly a consequence of its antioxidant and anti-inflammatory properties.

Anti-inflammatory and antifibrotic effects of methyl palmitate

Methyl palmitate (MP) has been shown earlier to inhibit Kupffer cells and rat peritoneal macrophages. To evaluate the potential of MP to inhibit the activation of other macrophages, RAW cells (macrophages of alveolar origin) were treated with varying concentrations of MP (0.25, 0.5, 1mM). Assessment of cytotoxicity using MTT assay revealed that 0.25 and 0.5mM are not toxic to RAW cells. MP was able to inhibit the phagocytic function of RAW cells. Treatment of cells with MP 24hours prior to LPS stimulation significantly decreased nitric oxide release and altered the pattern of cytokines release; there was a significant decrease in TNF-α and a significant increase in IL-10 compared to the controls. However, there is a non-significant change in IL-6 level. Furthermore, phosphorylation of inhibitory kappa B (IκBα) protein was significantly decreased in RAW cells treated with 0.5mM MP after LPS stimulation. Based upon the in-vitro results, it was examined whether MP treatment will be effective in preventing bleomycin-induced lung inflammation and fibrosis in-vivo. Bleomycin given by itself caused destruction of the lung architecture characterized by pulmonary fibrosis with collapse of air alveoli and emphysematous. Bleomycin induced a significant increase in hydroxyproline level and activated NF-κB, p65 expression in the lung. MP co-treatment significantly ameliorated bleomycin effects. These results suggest that MP has a potential of inhibiting macrophages in general. The present study demonstrated for the first time that MP has anti-inflammatory and antifibrotic effect that could be through NF-kB inhibition. Thus MP like molecule could be a promising anti-inflammatory and antifibrotic drug.

Effect of hyperhomocysteinemia on the protein kinase DYRK1A in liver of mice

Hyperhomocysteinemia due to cystathionine beta synthase (CBS)-deficiency confers diverse clinical manifestations, notably liver diseases. Even if hyperhomocysteinemia in liver of CBS-deficient mice, a murine model of hyperhomocysteinemia, promotes mitochondrial oxidative stress and pro-apoptotic signals, protective signals may counteract these pro-apoptotic signals, leading to chronic inflammation. As DYRK1A, a serine/threonine kinase, has been described as a candidate antiapoptotic factor, we have analyzed the expression of DYRK1A in liver of CBS-deficient mice. We found that DYRK1A protein level was reduced in liver of CBS-deficient mice, which was not observed at the gene expression level. Moreover, the use of primary hepatocytes/Kupffer cells co-culture showed that degradation of DYRK1A induced by hyperhomocysteinemia requires calpain activation. Our results demonstrate a deleterious effect of hyperhomocysteinemia on DYRK1A protein expression, and emphasize the role of hyperhomocysteinemia on calpain activation.

Methyl palmitate prevents CCl(4)-induced liver fibrosis

Liver fibrosis is characterized by an excess of collagen fiber deposition, and it is known that Kupffer cells play an important role by immunomodulation of the toxic response. Methyl palmitate (MP) is an effective Kupffer cell inhibitor. The aim of this work was to evaluate the effect of MP on experimental liver fibrosis. Four groups were formed: the control group, which received the vehicles only; CCl(4) group (0.4 g kg(-1), i.p., three times a week, for eight weeks); CCl(4) plus MP (300 mg kg(-1), i.p., daily); and MP alone. Alanine aminotransferase was increased by CCl(4), and MP did not prevent this increase. Lipid peroxidation was increased markedly by CCl(4); again, MP was not able to prevent this effect. Fibrosis increased nearly 6-fold (measured as liver hydroxyproline content) in the CCl(4) group; MP preserved the normal content of collagen. These results were corroborated by histopathology. To elucidate the antifibrogenic mechanism of MP, we measured the production of TGF-beta; CCl(4) increased this cytokine several-fold, and MP abolished this increase. Collectively the present results indicate that MP possesses a strong antifibrogenic effect at least in the CCl(4) model of fibrosis. The antifibrotic effect of MP is probably associated with its ability to reduce TGF-beta content, maybe by immunomodulation of Kupffer cells functioning.

Methyl palmitate inhibits lipopolysaccharide-stimulated phagocytic activity of rat peritoneal macrophages

Macrophages, in general, are critical effectors of body's immune system. Chemical inhibition of phagocytic activity of such macrophages as Kupffer cells has been extensively studied. We have earlier shown that methyl palmitate (MP) inhibits the activation of Kupffer cells. To evaluate the potential of MP to inhibit the activation of other macrophages, we treated rat peritoneal macrophages with varying concentrations of MP. Its treatment led to a dose-dependent inhibition of phagocytic activity, which was found to be 34%, 47%, and 66% at 0.25, 0.50, and 1.0 mM MP, respectively, as measured by latex bead uptake. When MP-treated peritoneal macrophages were stimulated with lipopolysaccharide (LPS), the nitric oxide (.NO) release was inhibited at 6 h, while cyclooxygenase-2 expression decreased after 24 h. The treatment with MP increased the release of interleukin (IL)-10 in the LPS-treated cells at 6 h, while IL-6 and tumor necrosis factor-alpha were significantly increased both at 6 and 24 h. Our data suggest that MP inhibits phagocytic activity and .NO production similar to that observed in isolated Kupffer cells. Therefore, inhibition of phagocytosis by MP may be a general phenomenon, and it could be used as an inhibitor of macrophage function.

Fatty acid control of nitric oxide production by macrophages

Modulation of macrophage functions by fatty acids (FA) has been studied by several groups, but the effect of FA on nitric oxide production by macrophages has been poorly examined. In the present study the effect of palmitic, stearic, oleic, linoleic, arachidonic, docosahexaenoic and eicosapentaenoic acids on NF-kappaB activity and NO production in J774 cells (a murine macrophage cell line) was investigated. All FA tested stimulated NO production at low doses (1-10 microM) and inhibited it at high doses (50-200 microM). An increase of iNOS expression and activity in J774 cells treated with a low concentration of FA (5 microM) was observed. The activity of NF-kappaB was time-dependently enhanced by the FA treatment. The inhibitory effect of FA on NO production may be due to their cytotoxicity, as observed by loss of membrane integrity and/or increase of DNA fragmentation in cells treated for 48 h with high concentrations. The results indicate that, at low concentrations FA increase NO production by J774 cells, whereas at high concentrations they cause cell death.