Nerve Growth Factor Signaling Modulates the Expression of Glutaminase in Dorsal Root Ganglion Neurons during Peripheral Inflammation.

Glutamate functions as the major excitatory neurotransmitter for primary sensory neurons and has a crucial role in sensitizing peripheral nociceptor terminals producing sensitization. Glutaminase (GLS) is the synthetic enzyme that converts glutamine to glutamate. GLS-immunoreactivity (-ir) and enzyme activity are elevated in dorsal root ganglion (DRG) neuronal cell bodies during chronic peripheral inflammation, but the mechanism for this GLS elevation is yet to be fully characterized. It has been well established that, after nerve growth factor (NGF) binds to its high-affinity receptor tropomyosin receptor kinase A (TrkA), a retrograde signaling endosome is formed. This endosome contains the late endosomal marker Rab7GTPase and is retrogradely transported via axons to the cell soma located in the DRG. This complex is responsible for regulating the transcription of several critical nociceptive genes. Here, we show that this retrograde NGF signaling mediates the expression of GLS in DRG neurons during the process of peripheral inflammation. We disrupted the normal NGF/TrkA signaling in adjuvant-induced arthritic (AIA) Sprague Dawley rats by the pharmacological inhibition of TrkA or blockade of Rab7GTPase, which significantly attenuated the expression of GLS in DRG cell bodies. The results indicate that NGF/TrkA signaling is crucial for the production of glutamate and has a vital role in the development of neurogenic inflammation. In addition, our pain behavioral data suggest that Rab7GTPase can be a potential target for attenuating peripheral inflammatory pain.

Nerve Growth Factor Shows Biphasic Expression during Adjuvant-Induced Neurogenic Inflammation.

Chronic inflammatory diseases are considered the most significant cause of death worldwide. Current treatments for inflammatory diseases are limited due to the lack of understanding of the biological factors involved in early-stage disease progression. Nerve growth factor (NGF) is a neurotrophic factor directly associated with inflammatory and autoimmune diseases like osteoarthritis, multiple sclerosis, and rheumatoid arthritis. It has been shown that NGF levels are significantly upregulated at the site of inflammation and play a crucial role in developing a robust inflammatory response. However, little is known about NGF's temporal expression profile during the initial progressive phase of inflammation. This study aimed to determine the temporal expression patterns of NGF in rat skin (epidermis) during adjuvant-induced arthritis (AIA). Sprague Dawley rats were randomly divided into control and complete Freund's adjuvant (CFA)-treated groups. Levels of NGF were evaluated following unilateral AIA at different time points, and it was found that peripheral inflammation due to AIA significantly upregulated the expression of NGF mRNA and protein in a biphasic pattern. These results suggest that NGF signaling is crucial for initiating and maintaining peripheral neurogenic inflammation in rats during AIA.

Gastrointestinal Cancer Therapeutics via Triggering Unfolded Protein Response and Endoplasmic Reticulum Stress by 2-Arylbenzofuran.

Gastrointestinal cancers are a major global health challenge, with high mortality rates. This study investigated the anti-cancer activities of 30 monomers extracted from Morus alba L. (mulberry) against gastrointestinal cancers. Toxicological assessments revealed that most of the compounds, particularly immunotoxicity, exhibit some level of toxicity, but it is generally not life-threatening under normal conditions. Among these components, Sanggenol L, Sanggenon C, Kuwanon H, 3'-Geranyl-3-prenyl-5,7,2',4'-tetrahydroxyflavone, Morusinol, Mulberrin, Moracin P, Kuwanon E, and Kuwanon A demonstrate significant anti-cancer properties against various gastrointestinal cancers, including colon, pancreatic, and gastric cancers. The anti-cancer mechanism of these chemical components was explored in gastric cancer cells, revealing that they inhibit cell cycle and DNA replication-related gene expression, leading to the effective suppression of tumor cell growth. Additionally, they induced unfolded protein response (UPR) and endoplasmic reticulum (ER) stress, potentially resulting in DNA damage, autophagy, and cell death. Moracin P, an active monomer characterized as a 2-arylbenzofuran, was found to induce ER stress and promote apoptosis in gastric cancer cells, confirming its potential to inhibit tumor cell growth in vitro and in vivo. These findings highlight the therapeutic potential of Morus alba L. monomers in gastrointestinal cancers, especially focusing on Moracin P as a potent inducer of ER stress and apoptosis.

A four-part guide to lung immunology: Invasion, inflammation, immunity, and intervention.

Lungs are important respiratory organs primarily involved in gas exchange. Lungs interact directly with the environment and their primary function is affected by several inflammatory responses caused by allergens, inflammatory mediators, and pathogens, eventually leading to disease. The immune architecture of the lung consists of an extensive network of innate immune cells, which induce adaptive immune responses based on the nature of the pathogen(s). The balance of immune responses is critical for maintaining immune homeostasis in the lung. Infection by pathogens and physical or genetic dysregulation of immune homeostasis result in inflammatory diseases. These responses culminate in the production of a plethora of cytokines such as TSLP, IL-9, IL-25, and IL-33, which have been implicated in the pathogenesis of several inflammatory and autoimmune diseases. Shifting the balance of Th1, Th2, Th9, and Th17 responses have been the targets of therapeutic interventions in the treatment of these diseases. Here, we have briefly reviewed the innate and adaptive i3mmune responses in the lung. Genetic and environmental factors, and infection are the major causes of dysregulation of various functions of the lung. We have elaborated on the impact of inflammatory and infectious diseases, advances in therapies, and drug delivery devices on this critical organ. Finally, we have provided a comprehensive compilation of different inflammatory and infectious diseases of the lungs and commented on the pros and cons of different inhalation devices for the management of lung diseases. The review is intended to provide a summary of the immunology of the lung, with an emphasis on drug and device development.

Separation of Rat Epidermis and Dermis with Thermolysin to Detect Site-Specific Inflammatory mRNA and Protein.

Easy-to-use and inexpensive techniques are needed to determine the site-specific production of inflammatory mediators and neurotrophins during skin injury, inflammation, and/or sensitization. The goal of this study is to describe an epidermal-dermal separation protocol using thermolysin, a proteinase that is active at 4 °C. To illustrate this procedure, Sprague Dawley rats are anesthetized, and right hind paws are injected with carrageenan. Six and twelve hours after injection, rats with inflammation and naïve rats are euthanized, and a piece of hind paw, glabrous skin is placed in cold Dulbecco's Modified Eagle Medium. The epidermis is then separated at the basement membrane from the dermis by thermolysin in PBS with calcium chloride. Next, the dermis is secured by microdissection forceps, and the epidermis is gently teased away. Toluidine blue staining of tissue sections show that the epidermis is separated cleanly from the dermis at the basement membrane. All keratinocyte cell layers remain intact, and the epidermal rete ridges along with indentations from dermal papillae are clearly observed. Qualitative and real-time RT-PCR is used to determine nerve growth factor and interleukin-6 expression levels. Western blotting and immunohistochemistry are finally performed to detect amounts of nerve growth factor. This report illustrates that cold thermolysin digestion is an effective method to separate epidermis from dermis for evaluation of mRNA and protein alterations during inflammation.