Developmental changes in hypothalamic toll‐like‐receptor 4 mRNA expression and the effects of lipopolysaccharide on such changes in female rats

The purpose of this study was to examine the influence of resistive exercise training and hormone status on mRNA expression of toll-like receptor 4 (TLR4), CD14, IL-1β, IL-6, and TNF-α. Resistive exercise-trained women on “traditional” hormone replacements [hormone replacement therapy (HRT), n = 9], not taking hormones (NHR, n = 6), or taking medications known to influence bone (MIB, n = 7) were compared with untrained subjects not taking supplemental hormones (Con, n = 6). Blood was taken from trained subjects before, immediately after, and 2 h after resistive exercise (same time points for resting Con). TLR4 mRNA expression (RT-PCR) was not different among groups or across time but was significantly ( P = 0.044) lower (1.9-fold) when trained groups were collapsed and compared with Con. There was also a significant group effect ( P < 0.0001) for TLR4 mRNA when expressed per monocyte. CD14 expression was significantly ( P = 0.006) lower (2.3-fold) for training groups collapsed and compared with Con. CD14 mRNA, expressed per monocyte, was significantly lower immediately after resistive exercise for NHR, HRT, and MIB compared with Con. There were few significant effects detected for IL-6, IL-1β, and TNF-α mRNA, but there was a significant group effect ( P < 0.0001) for TNF-α mRNA expressed per monocyte (Con > HRT, NHR, MIB). These findings suggest that there may be a resistive exercise training-induced reduction in TLR4/CD14 expression in older women. Further research is needed to determine whether lower TLR4/CD14 could explain the lower LPS-stimulated inflammatory cytokines observed in these women.

Download Full-text

Atorvastatin suppresses LPS-induced rapid upregulation of Toll-like receptor 4 and its signaling pathway in endothelial cells

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.01335.2008 ◽

2011 ◽

Vol 300 (5) ◽

pp. H1743-H1752 ◽

Cited By ~ 38

Author(s):

Ying Wang ◽

Ming Xiang Zhang ◽

Xiao Meng ◽

Fu Qiang Liu ◽

Guang Sheng Yu ◽

...

Keyword(s):

Endothelial Cells ◽

Mrna Expression ◽

Signaling Pathways ◽

P38 Mapk ◽

Umbilical Vein ◽

Enzyme Linked Immunosorbent Assay ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Mapk Phosphorylation ◽

Tlr4 Mrna

In the present study, we tested our hypothesis that atorvastatin exerts its anti-inflammation effect via suppressing LPS-induced rapid upregulation of Toll-like receptor 4 (TLR4) mRNA and its downstream p38, ERK, and NF-κB signaling pathways in human umbilical-vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs). TLR4 mRNA expression and its downstream kinase activities induced by LPS alone or atorvastatin + LPS in endothelial cells were quantified using quantitative real-time PCR and enzyme-linked immunosorbent assay. Preincubation of LPS-stimulated endothelial cells with TLR4 siRNA was conducted to identify the target of the anti-inflammatory effects of atorvastatin. Atorvastatin incubation resulted in the reduction of LPS-induced TLR4 mRNA expression, ERK1/2 and P38 MAPK phosphorylation, and NF-κB binding activity. Pretreatment with MEK/ERK1/2 inhibitor PD98059 attenuated atorvastatin + LPS-induced NF-κB activity but had no effect on P38 MAPK phosphorylation. In contrast, pretreatment with P38 MAPK inhibitor SB203580 resulted in upregulation of atorvastatin + LPS-induced ERK1/2 phosphorylation but had no significant effects on NF-κB activity. On the other hand, blocking NF-κB with SN50 produced no effects on atorvastatin + LPS-induced ERK1/2 and P38 MAPK phosphorylation. Moreover, TLR4 gene silencing produced the same effects as the atorvastatin treatment. In conclusion, atorvastatin downregulated TLR4 mRNA expression by two distinct signaling pathways. First, atorvastatin stabilized Iκ-Bα, which directly inhibited NF-κB activation. Second, atorvastatin inactivated ERK phosphorylation, which indirectly inhibited NF-κB activation. Suppression of p38 MAPK by atorvastatin upregulates ERK but exerts no effect on NF-κB.

Download Full-text

Asparagine attenuates hepatic injury caused by lipopolysaccharide in weaned piglets associated with modulation of Toll-like receptor 4 and nucleotide-binding oligomerisation domain protein signalling and their negative regulators

British Journal Of Nutrition ◽

10.1017/s0007114515001476 ◽

2015 ◽

Vol 114 (2) ◽

pp. 189-201 ◽

Cited By ~ 4

Author(s):

Huanting Wu ◽

Yulan Liu ◽

Dingan Pi ◽

Weibo Leng ◽

Huiling Zhu ◽

...

Keyword(s):

Protein Expression ◽

Mrna Expression ◽

Nucleotide Binding ◽

Toll Like Receptor ◽

Negative Regulators ◽

Toll Like Receptor 4 ◽

Signalling Molecules ◽

Lps Challenge ◽

Tnf Α ◽

Domain Protein

Pro-inflammatory cytokines play a key role in many models of hepatic damage. In addition, asparagine (Asn) plays an important role in immune function. We aimed to investigate whether Asn could attenuate lipopolysaccharide (LPS)-induced liver damage. Forty-eight castrated barrows were allotted to four groups including: (1) non-challenged control; (2) LPS-challenged control; (3) LPS+0·5 % Asn; and (4) LPS+1·0 % Asn. After 19 d feeding with control, 0·5 or 1·0 % Asn diets, pigs were injected with LPS or saline. Blood and liver samples were obtained at 4 h (early stage) and 24 h (late stage) post-injection. Asn alleviated liver injury, indicated by reduced serum aspartate aminotransferase and alkaline phosphatase activities linearly and quadratically; it increased claudin-1 protein expression linearly and quadratically at 24 h, and less severe liver morphological impairment at 4 or 24 h. In addition, Asn decreased mRNA expression of TNF-α and heat shock protein 70 (HSP70) linearly and quadratically at 4 h; it increased TNF-α mRNA expression, and HSP70 protein expression linearly and quadratically at 24 h. Moreover, Asn increased inducible NO synthase activity linearly and quadratically. Finally, Asn down-regulated the mRNA expression of Toll-like receptor 4 (TLR4) signalling molecules (TLR4, IL-1 receptor-associated kinase 1 (IRAK1), TNF-α receptor-associated factor 6), nucleotide-binding oligomerisation domain protein (NOD) signalling molecules (NOD1, NOD2 and their adaptor molecule receptor-interacting serine/threonine-protein kinase 2 (RIPK2)), and NF-κB p65 linearly or quadratically at 4 h. Oppositely, Asn up-regulated mRNA expressions of TLR4 and NOD signalling molecules (TLR4, myeloid differentiation factor 88, IRAK1, NOD2 and RIPK2), and their negative regulators (radioprotective 105, single Ig IL-1R-related molecule, Erbb2 interacting protein and centaurin β1) linearly or quadratically at 24 h. These results indicate that, in early and late stages of LPS challenge, Asn improves liver integrity and exerts different regulatory effects on mRNA expression of TLR4 and NOD signalling molecules.

Download Full-text

Sensitivities of mRNA expression levels of Kiss1 and its receptor, Kiss1r, to nutritional status are changed during the developmental period in female rats

Journal of Endocrinology ◽

10.1677/joe-10-0129 ◽

2010 ◽

Vol 207 (2) ◽

pp. 195-202 ◽

Cited By ~ 18

Author(s):

Takeshi Iwasa ◽

Toshiya Matsuzaki ◽

Masahiro Murakami ◽

Riyo Kinouchi ◽

Ganbat Gereltsetseg ◽

...

Keyword(s):

Nutritional Status ◽

Mrna Expression ◽

Neonatal Period ◽

Mrna Level ◽

Reproductive Function ◽

Developmental Period ◽

Developmental Changes ◽

Female Rats ◽

Neuronal Systems ◽

Plasma Leptin

Decreased activity of kisspeptin, the product of the hypothalamic Kiss1 gene, is the major cause of the suppression of reproductive function in subnutritional conditions. The sensitivities of the endocrine and the hypothalamic neuronal systems to nutritional status develop during the neonatal period. We examined the developmental changes in the sensitivity of hypothalamic mRNA expression of Kiss1 and its receptor, Kiss1r, to nutritional status in female rats. Kiss1 mRNA expression was reduced by 24 h food deprivation (24 h FD) at postnatal day 25, but not at postnatal day 5 or 15. Kiss1r mRNA expression was reduced by the 12 or 24 h FD at postnatal days 5 and 25, but not at postnatal day 15. Kiss1r mRNA level was found to be correlated with the plasma leptin level, and the administration of leptin, which increased the serum leptin concentration above the physiological range, restored the acute FD-induced suppression of Kiss1r mRNA expression. These data suggest that the hypothalamic Kiss1 and Kiss1r mRNA expression is differentially affected by the nutritional condition at different age points. It is speculated that the sensitivity of Kiss1 mRNA, which is expressed in kisspeptin neuron, to nutritional status develops during the neonatal period. On the other hand, it seems that the sensitivity of Kiss1r mRNA, which is expressed in GnRH neuron, to nutritional status has been already established during the early neonatal period. These data also show that hypoleptinemia plays a role in the reduction of hypothalamic Kiss1r mRNA expression under subnutritional conditions.

Download Full-text

Vitamin D inhibits lipopolysaccharide-induced inflammatory response potentially through the Toll-like receptor 4 signalling pathway in the intestine and enterocytes of juvenile Jian carp (Cyprinus carpio var. Jian)

British Journal Of Nutrition ◽

10.1017/s0007114515003256 ◽

2015 ◽

Vol 114 (10) ◽

pp. 1560-1568 ◽

Cited By ~ 21

Author(s):

Jun Jiang ◽

Dan Shi ◽

Xiao-Qiu Zhou ◽

Long Yin ◽

Lin Feng ◽

...

Keyword(s):

Vitamin D ◽

Inflammatory Response ◽

Mrna Expression ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Jian Carp ◽

Pre Treatment ◽

Inflammatory Effect

AbstractThe present study was conducted to investigate the anti-inflammatory effect of vitamin D both in juvenile Jian carp (Cyprinus carpio var. Jian) in vivo and in enterocytes in vitro. In primary enterocytes, exposure to 10 mg lipopolysaccharide (LPS)/l increased lactate dehydrogenase activity in the culture medium (P<0·05) and resulted in a significant loss of cell viability (P<0·05). LPS exposure increased (P<0·05) the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8), which was decreased by pre-treatment with 1,25-dihydroxyvitamin D (1,25D3) in a dose-dependent manner (P<0·05). Further results showed that pre-treatment with 1,25D3 down-regulated Toll-like receptor 4 (TLR4), myeloid differentiation primary response gene 88 (Myd88) and NF-κB p65 mRNA expression (P<0·05), suggesting potential mechanisms against LPS-induced inflammatory response. In vivo, intraperitoneal injection of LPS significantly increased TNF-α, IL-1β, IL-6 and IL-8 mRNA expression in the intestine of carp (P<0·05). Pre-treatment of fish with vitamin D3 protected the fish intestine from the LPS-induced increase of TNF-α, IL-1β, IL-6 and IL-8 mainly by downregulating TLR4, Myd88 and NF-κB p65 mRNA expression (P<0·05). These observations suggest that vitamin D could inhibit LPS-induced inflammatory response in juvenile Jian carp in vivo and in enterocytes in vitro. The anti-inflammatory effect of vitamin D is mediated at least in part by TLR4-Myd88 signalling pathways in the intestine and enterocytes of juvenile Jian carp.

Download Full-text

Ventricular TLR4 Levels Abrogate TLR2-Knockout-Mediated Adverse Cardiac Remodeling upon Pressure Overload in Mice

International Journal of Molecular Sciences ◽

10.3390/ijms222111823 ◽

2021 ◽

Vol 22 (21) ◽

pp. 11823

Author(s):

Elise L. Kessler ◽

Jiong-Wei Wang ◽

Bart Kok ◽

Maike A. Brans ◽

Angelique Nederlof ◽

...

Keyword(s):

Mrna Expression ◽

Cardiac Remodeling ◽

Pressure Overload ◽

Heart Weight ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Cross Sectional ◽

Tlr4 Mrna ◽

Tibia Length

Involvement of the Toll-like receptor 4 (TLR4) in maladaptive cardiac remodeling and heart failure (HF) upon pressure overload has been studied extensively, but less is known about the role of TLR2. Interplay and redundancy of TLR4 with TLR2 have been reported in other organs but were not investigated during cardiac dysfunction. We explored whether TLR2 deficiency leads to less adverse cardiac remodeling upon chronic pressure overload and whether TLR2 and TLR4 additively contribute to this. We subjected 35 male C57BL/6J mice (wildtype (WT) or TLR2 knockout (KO)) to sham or transverse aortic constriction (TAC) surgery. After 12 weeks, echocardiography and electrocardiography were performed, and hearts were extracted for molecular and histological analysis. TLR2 deficiency (n = 14) was confirmed in all KO mice by PCR and resulted in less hypertrophy (heart weight to tibia length ratio (HW/TL), smaller cross-sectional cardiomyocyte area and decreased brain natriuretic peptide (BNP) mRNA expression, p < 0.05), increased contractility (QRS and QTc, p < 0.05), and less inflammation (e.g., interleukins 6 and 1β, p < 0.05) after TAC compared to WT animals (n = 11). Even though TLR2 KO TAC animals presented with lower levels of ventricular TLR4 mRNA than WT TAC animals (13.2 ± 0.8 vs. 16.6 ± 0.7 mg/mm, p < 0.01), TLR4 mRNA expression was increased in animals with the largest ventricular mass, highest hypertrophy, and lowest ejection fraction, leading to two distinct groups of TLR2 KO TAC animals with variations in cardiac remodeling. This variation, however, was not seen in WT TAC animals even though heart weight/tibia length correlated with expression of TLR4 in these animals (r = 0.078, p = 0.005). Our data suggest that TLR2 deficiency exacerbates adverse cardiac remodeling and that ventricular TLR2 and TLR4 additively contribute to adverse cardiac remodeling during chronic pressure overload. Therefore, both TLRs may be therapeutic targets to prevent or interfere in the underlying molecular processes.

Download Full-text

Western diet (WD) activates pancreatic Toll‐like receptor 4 (TLR4) signaling in female rats: a potential mechanism of WD‐induced insulin resistance

The FASEB Journal ◽

10.1096/fasebj.2020.34.s1.06807 ◽

2020 ◽

Vol 34 (S1) ◽

pp. 1-1

Author(s):

Shilpa Mathew ◽

Risa Kiernan ◽

Nicole Maddie ◽

Maria Alicia Carrillo-Sepulveda

Keyword(s):

Insulin Resistance ◽

Western Diet ◽

Female Rats ◽

Potential Mechanism ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Tlr4 Signaling

Download Full-text

Medium-chain TAG improve intestinal integrity by suppressing toll-like receptor 4, nucleotide-binding oligomerisation domain proteins and necroptosis signalling in weanling piglets challenged with lipopolysaccharide

British Journal Of Nutrition ◽

10.1017/s000711451800003x ◽

2018 ◽

Vol 119 (9) ◽

pp. 1019-1028 ◽

Cited By ~ 8

Author(s):

Xiao Xu ◽

Shaokui Chen ◽

Haibo Wang ◽

Zhixiao Tu ◽

Shuhui Wang ◽

...

Keyword(s):

Protein Expression ◽

Mrna Expression ◽

Nucleotide Binding ◽

Intestinal Morphology ◽

Toll Like Receptor ◽

Toll Like Receptor 4 ◽

Medium Chain ◽

Intestinal Integrity ◽

Weanling Piglets ◽

Maize Oil

AbstractThis study was conducted to evaluate whether medium-chain TAG (MCT) could alleviate Escherichia coli lipopolysaccharide (LPS)-induced intestinal injury by regulating intestinal epithelial inflammatory response, as well as necroptosis. A total of twenty-four weanling piglets were randomly allotted to one of four treatments in a 2×2 factorial arrangement including diet type (5 % maize oil v. 4 % MCT+1 % maize oil) and immune stress (saline v. E. coli LPS). The piglets were fed diets containing maize oil or MCT for 21 d. On 21 d, piglets were injected intraperitoneally with saline or LPS. The blood and intestinal samples were collected at 4 h post injection. Supplementation with MCT improved intestinal morphology, digestive and barrier function, indicated by increased jejunal villus height, increased jejunal and ileal disaccharidases (sucrase and maltase) activities, as well as enhanced protein expression of claudin-1. Furthermore, the protein expression of heat-shock protein 70 in jejunum and the concentration of TNF-α in plasma were reduced in the piglets fed diets supplemented with MCT. In addition, MCT down-regulated the mRNA expression of toll-like receptor 4 (TLR4) and nucleotide-binding oligomerisation domain proteins (NOD) signalling-related genes in jejunum and ileum. Finally, MCT inhibited jejunal and ileal enterocyte necroptosis indicated by suppressed mRNA expression of the receptor-interacting protein 3 and mixed-lineage kinase domain-like protein. These results indicate that MCT supplementation may be closely related to inhibition of TLR4, NOD and necroptosis signalling pathways and concomitant improvement of intestinal integrity under an inflammatory condition.

Download Full-text