LPS-Induced Production of Inflammatory Mediators in the Liver of Postnatal Animals

Lipopolysaccharide (LPS) is the primary component of the outer membrane of Gram-negative bacteria and is responsible for the majority of inflammatory effects of infections from Gram-negative bacteria. To gain better understanding of the effects that postnatal age has on the inflammatory response, pups were randomly assigned to be treated with 250 µg/kg of LPS or saline at postnatal day (P) 1, P21, and P70. Two hours post stimulation, the pups were sacrificed and their livers were harvested for total RN A extraction. Relative mRNA levels of inflammatory genes and �-actin were determined using RT-PCR analysis with appropriate rat sense and antisense primers. The specific inflammatory mediators examined were toll-like receptor-4 (TLR4), cluster of differentiation 14 (CD14), myeloid differentiation factor 88 (Myd88), cytokines including interleukin (IL )-1 �. IL-6, and tumor necrosis factor (TNF)-a, and chemokines including macrophage inflammatory protein (MIP)-1 �, MIP-2, and monocyte chemotactic protein (MCP)-1. We found that the LPS-induced mRNA expression of the cytokines and chemokines examined appear to be increased as compared to the control pups. Furthermore, we showed that an activation of cytokines and chemokines in the liver exhibited age-dependency in pups treated with LPS at Pl, P21, and P70. The pattern shows an increase in relative mRNA expression of cytokines and chemokines as development progresses. Furthermore, we compared the kinetics of cytokine and chemokine induction in PI and P2 l animals. We found that that there was a delayed cytokine and chemokine induction at PI as compared to P2 l pups. Our data suggest that the hepatic innate immunity undergo significant development during early postnatal development, and the delayed inflammatory response in Pl animals may contribute to increased susceptibility of neonatal animals to infections

7‑hydroxymitragynine is an active metabolite of mitragynine and a key mediator of its analgesic effects

Mitragynina speciosa, more commonly known as kratom, is a plant native to Southeast Asia, the leaves of which have been used traditionally as a stimulant, analgesic, and treatment for opioid addiction. Recently, growing use of the plant in the United States and concerns that kratom represents an uncontrolled drug with potential abuse liability, have highlighted the need for more careful study of its pharmacological activity. The major active alkaloid found in kratom, mitragynine, has been reported to have opioid agonist and analgesic activity in vitro and in animal models, consistent with the purported effects of kratom leaf in humans. However, preliminary research has provided some evidence that mitragynine and related compounds may act as atypical opioid agonists, inducing therapeutic effects such as analgesia, while limiting the negative side effects typical of classical opioids. Here we report evidence that an active metabolite plays an important role in mediating the analgesic effects of mitragynine. We find that mitragynine is converted in vitro in both mouse and human liver preparations to the much more potent mu-opioid receptor agonist 7-hydroxymitragynine, and that this conversion is mediated by cytochrome P450 3A isoforms. Further, we show that 7-hydroxymitragynine is formed from mitragynine in mice and that brain concentrations of this metabolite are sufficient to explain most or all of the opioid-receptor-mediated analgesic activity of mitragynine. At the same time, mitragynine is found in the brains of mice at very high concentrations relative to its opioid receptor binding affinity, suggesting that it does not directly activate opioid receptors. The results presented here provide a metabolism-dependent mechanism for the analgesic effects of mitragynine and clarify the importance of route of administration for determining the activity of this compound. Further, they raise important questions about the interpretation of existing data on mitragynine and highlight critical areas for further research in animals and humans.</p

Postnatal Development of Hepatic Innate Immune Response

The liver is an immunocompetent organ that plays a key role in the immune response to infections, and the development of hepatic immune function during early postnatal stages has not been thoroughly characterized. This study analyzed the constitutive expression of complement factors, namely C3 and C9, and pattern recognition receptors, namely CD14, toll-like receptor (TLR)-4, and lipopolysaccharide binding protein (LBP), in the liver of postnatal day (P)1, P21, and P70 rats, and compared the kinetics of induction of cytokines and chemokines in the liver of P 1 and P 21 animals. Our studies found that while the mRNA expression of C3, C9, CD14, and TLR-4 was lower in P1 animals, the mRNA level of LBP was higher in P1 animals as compared to older animals, and that the kinetics of induction of cytokines and chemokines was significantly delayed in P1 as compared to P21 liver following LPS stimulation. Our data suggest that hepatic innate immunity is deficient in the neonates and undergo significant development during early postnatal life

LPS-Induced Production of Inflammatory Mediators in the Liver of Postnatal Animals

Lipopolysaccharide (LPS) is the primary component of the outer membrane of Gram-negative bacteria and is responsible for the majority of inflammatory effects of infections from Gram-negative bacteria. To gain better understanding of the effects that postnatal age has on the inflammatory response, pups were randomly assigned to be treated with 250 µg/kg of LPS or saline at postnatal day (P) 1, P21, and P70. Two hours post stimulation, the pups were sacrificed and their livers were harvested for total RN A extraction. Relative mRNA levels of inflammatory genes and �-actin were determined using RT-PCR analysis with appropriate rat sense and antisense primers. The specific inflammatory mediators examined were toll-like receptor-4 (TLR4), cluster of differentiation 14 (CD14), myeloid differentiation factor 88 (Myd88), cytokines including interleukin (IL )-1 �. IL-6, and tumor necrosis factor (TNF)-a, and chemokines including macrophage inflammatory protein (MIP)-1 �, MIP-2, and monocyte chemotactic protein (MCP)-1. We found that the LPS-induced mRNA expression of the cytokines and chemokines examined appear to be increased as compared to the control pups. Furthermore, we showed that an activation of cytokines and chemokines in the liver exhibited age-dependency in pups treated with LPS at Pl, P21, and P70. The pattern shows an increase in relative mRNA expression of cytokines and chemokines as development progresses. Furthermore, we compared the kinetics of cytokine and chemokine induction in PI and P2 l animals. We found that that there was a delayed cytokine and chemokine induction at PI as compared to P2 l pups. Our data suggest that the hepatic innate immunity undergo significant development during early postnatal development, and the delayed inflammatory response in Pl animals may contribute to increased susceptibility of neonatal animals to infections

Viral Subversion of the Nuclear Pore Complex

The nuclear pore complex (NPC) acts as a selective barrier between the nucleus and the cytoplasm and is responsible for mediating communication by regulating the transport of RNA and proteins. Numerous viral pathogens have evolved different mechanisms to hijack the NPC in order to regulate trafficking of viral proteins, genomes and even capsids into and out of the nucleus thus promoting virus replication. The present review examines the different strategies and the specific nucleoporins utilized during viral infections as a means of promoting their life cycle and inhibiting host viral defenses

7-Hydroxymitragynine is an Active Metabolite of Mitragynine and a Key Mediator of its Analgesic Effects

Mitragynina speciosa, more commonly known as kratom, is a plant native to Southeast Asia, the leaves of which have been used traditionally as a stimulant, analgesic, and treatment for opioid addiction. Recently, growing use of the plant in the United States and concerns that kratom represents an uncontrolled drug with potential abuse liability, have highlighted the need for more careful study of its pharmacological activity. The major active alkaloid found in kratom, mitragynine, has been reported to have opioid agonist and analgesic activity in vitro and in animal models, consistent with the purported effects of kratom leaf in humans. However, preliminary research has provided some evidence that mitragynine and related compounds may act as atypical opioid agonists, inducing therapeutic effects such as analgesia, while limiting the negative side effects typical of classical opioids. Here we report evidence that an active metabolite plays an important role in mediating the analgesic effects of mitragynine. We find that mitragynine is converted in vitro in both mouse and human liver preparations to the much more potent mu-opioid receptor agonist 7-hydroxymitragynine, and that this conversion is mediated by cytochrome P450 3A isoforms. Further, we show that 7-hydroxymitragynine is formed from mitragynine in mice and that brain concentrations of this metabolite are sufficient to explain most or all of the opioid-receptor-mediated analgesic activity of mitragynine. At the same time, mitragynine is found in the brains of mice at very high concentrations relative to its opioid receptor binding affinity, suggesting that it does not directly activate opioid receptors. The results presented here provide a metabolism-dependent mechanism for the analgesic effects of mitragynine and clarify the importance of route of administration for determining the activity of this compound. Further, they raise important questions about the interpretation of existing data on mitragynine and highlight critical areas for further research in animals and humans.</p