Methamphetamine Induces Systemic Inflammation and Anxiety: The Role of the Gut-Immune-Brain Axis.

Methamphetamine (METH) is a highly addictive drug abused by millions of users worldwide, thus becoming a global health concern with limited management options. The inefficiency of existing treatment methods has driven research into understanding the mechanisms underlying METH-induced disorders and finding effective treatments. This study aims to understand the complex interactions of the gastrointestinal-immune-nervous systems following an acute METH dose administration as one of the potential underlying molecular mechanisms concentrating on the impact of METH abuse on gut permeability. Findings showed a decreased expression of tight junction proteins ZO-1 and EpCAm in intestinal tissue and the presence of FABP-1 in sera of METH treated mice suggests intestinal wall disruption. The increased presence of CD45+ immune cells in the intestinal wall further confirms gut wall inflammation/disruption. In the brain, the expression of inflammatory markers Ccl2, Cxcl1, IL-1ß, TMEM119, and the presence of albumin were higher in METH mice compared to shams, suggesting METH-induced blood-brain barrier disruption. In the spleen, cellular and gene changes are also noted. In addition, mice treated with an acute dose of METH showed anxious behavior in dark and light, open field, and elevated maze tests compared to sham controls. The findings on METH-induced inflammation and anxiety may provide opportunities to develop effective treatments for METH addiction in the future.

Divergent Adaptations in Autonomic Nerve Activity and Neuroimmune Signaling Associated With the Severity of Inflammation in Chronic Colitis.

BACKGROUND: The autonomic nervous system (ANS) is thought to play a critical role in the anti-inflammatory reflex pathway in acute colitis via its interaction with the spleen and colon. Inflammation in the intestine is associated with a blunting of vagal signaling and increased sympathetic activity. As a corollary, methods to restore sympatho-vagal balance are being investigated as therapeutic strategies for the treatment of intestinal inflammation. Nevertheless, it is indefinite whether these autonomic signaling adaptations in colitis are detrimental or beneficial to controlling intestinal inflammation. In this study, models of moderate and severe chronic colitis are utilized to resolve the correlations between sympatho-vagal signaling and the severity of intestinal inflammation. METHODS: Spleens and colons were collected from Winnie (moderate colitis), Winnie-Prolapse (severe colitis), and control C57BL/6 mice. Changes to the size and histomorphology of spleens were evaluated. Flow cytometry was used to determine the expression of adrenergic and cholinergic signaling proteins in splenic B and T lymphocytes. The inflammatory profile of the spleen and colon was determined using a RT-PCR gene array. Blood pressure, heart rate, splanchnic sympathetic nerve and vagus nerve activity were recorded. RESULTS: Spleens and colons from Winnie and Winnie-Prolapse mice exhibited gross abnormalities by histopathology. Genes associated with a pro-inflammatory response were upregulated in the colons from Winnie and further augmented in colons from Winnie-Prolapse mice. Conversely, many pro-inflammatory markers were downregulated in the spleens from Winnie-Prolapse mice. Heightened activity of the splanchnic nerve was observed in Winnie but not Winnie-Prolapse mice. Conversely, vagal nerve activity was greater in Winnie-Prolapse mice compared with Winnie mice. Splenic lymphocytes expressing α1 and ß2 adrenoreceptors were reduced, but those expressing α7 nAChR and producing acetylcholine were increased in Winnie and Winnie-Prolapse mice. CONCLUSIONS: Sympathetic activity may correlate with an adaptive mechanism to reduce the severity of chronic colitis. The Winnie and Winnie-Prolapse mouse models of moderate and severe chronic colitis are well suited to examine the pathophysiology of progressive chronic intestinal inflammation.

In this study we use mouse models of moderate and severe colitis to resolve the relationship between autonomic and neuroimmune signaling with inflammation. Increased expression of cholinergic markers on immune cells correlated with an anti-inflammatory profile in the spleen, consistent with activation of the splenic cholinergic anti-inflammatory pathway in mice with spontaneous chronic colitis. However, enhanced sympathetic signaling occurred in mice with a less severe phenotype of colitis, which could represent an adaptive mechanism to mitigate the progression of intestinal inflammation.

Anti-Cancer Effects of Carnosine-A Dipeptide Molecule.

BACKGROUND: Carnosine is a dipeptide molecule (ß-alanyl-l-histidine) with anti-inflammatory, antioxidant, anti-glycation, and chelating properties. It is used in exercise physiology as a food supplement to increase performance; however, in vitro evidence suggests that carnosine may exhibit anti-cancer properties. METHODS: In this study, we investigated the effect of carnosine on breast, ovarian, colon, and leukemic cancer cell proliferation. We further examined U937 promonocytic, human myeloid leukemia cell phenotype, gene expression, and cytokine secretion to determine if these are linked to carnosine's anti-proliferative properties. RESULTS: Carnosine (1) inhibits breast, ovarian, colon, and leukemic cancer cell proliferation; (2) upregulates expression of pro-inflammatory molecules; (3) modulates cytokine secretion; and (4) alters U937 differentiation and phenotype. CONCLUSION: These effects may have implications for a role for carnosine in anti-cancer therapy.

Anti-cancer effects of polyphenol-rich sugarcane extract.

Plant polyphenols have an array of health benefits primarily thought to be related to their high content of anti-oxidants. These are commonly undervalued and knowledge of their biological properties have grown exponentially in the last decade. Polyphenol-rich sugarcane extract (PRSE), a natural extract from sugar cane, is marketed as high in anti-oxidants and polyphenols, but its anti-cancer activity has not been reported previously. We show that, PRSE exerts anti-cancer properties on a range of cancer cells including human (LIM2045) and mouse (MC38, CT26) colon cancer cells lines; human lung cancer (A549), human ovarian cancer (SKOV-3), pro-monocytic human leukemia (U937) and to mouse melanoma (B16) cell lines; whereas no effects were noted on human breast (ZR-75-1) and human colon (HT29) cancer cell lines, as well as to human normal colon epithelial cell line (T4056). Anti-proliferative effects were shown to be mediated via alteration in cytokines, VEGF-1 and NF-κB expression.

Anti-Tumor Effects of Vitamin B2, B6 and B9 in Promonocytic Lymphoma Cells.

Chronic inflammation can lead to tumour initiation and progression. Vitamin B complex has the ability to regulate the immune response and, therefore, inflammation but many of the mechanistic and molecular processes involved in this regulation are still not fully understood. This study sought to determine some of these processes by studying the effects of vitamin B2 (riboflavin) B6 (pyridoxine) and B9 (folic acid) on un-differentiated pro-monocytic lymphoma cells in regard to their ability to alter the proliferation, migration, apoptosis, cytokines and expression levels of programmed death ligand 1. We show that vitamin B2, B6 and B9, on pro-monocytic lymphoma cells exerted an anti-tumorigenic effect. This data could form the basis for future studies in using vitamin B supplementation to reduce cancer cell growth in vivo.

A transgenic zebrafish model of hepatocyte function in human Z α1-antitrypsin deficiency.

In human α1-antitrypsin deficiency, homozygous carriers of the Z (E324K) mutation in the gene SERPINA1 have insufficient circulating α1-antitrypsin and are predisposed to emphysema. Misfolding and accumulation of the mutant protein in hepatocytes also causes endoplasmic reticulum stress and underpins long-term liver damage. Here, we describe transgenic zebrafish (Danio rerio) expressing the wildtype or the Z mutant form of human α1-antitrypsin in hepatocytes. As observed in afflicted humans, and in rodent models, about 80% less α1-antitrypsin is evident in the circulation of zebrafish expressing the Z mutant. Although these zebrafish also show signs of liver stress, they do not accumulate α1-antitrypsin in hepatocytes. This new zebrafish model will provide useful insights into understanding and treatment of α1-antitrypsin deficiency.

Therapeutic Cancer Vaccines-T Cell Responses and Epigenetic Modulation.

There is great interest in developing efficient therapeutic cancer vaccines, as this type of therapy allows targeted killing of tumor cells as well as long-lasting immune protection. High levels of tumor-infiltrating CD8+ T cells are associated with better prognosis in many cancers, and it is expected that new generation vaccines will induce effective production of these cells. Epigenetic mechanisms can promote changes in host immune responses, as well as mediate immune evasion by cancer cells. Here, we focus on epigenetic modifications involved in both vaccine-adjuvant-generated T cell immunity and cancer immune escape mechanisms. We propose that vaccine-adjuvant systems may be utilized to induce beneficial epigenetic modifications and discuss how epigenetic interventions could improve vaccine-based therapies. Additionally, we speculate on how, given the unique nature of individual epigenetic landscapes, epigenetic mapping of cancer progression and specific subsequent immune responses, could be harnessed to tailor therapeutic vaccines to each patient.

Methamphetamine: Effects on the brain, gut and immune system.

Methamphetamine (METH) is a powerful central nervous system stimulant which elevates mood, alertness, energy levels and concentration in the short-term. However, chronic use and/or at higher doses METH use often results in psychosis, depression, delusions and violent behavior. METH was formerly used to treat conditions such as obesity and attention deficit hyperactivity disorder, but now is primarily used recreationally. Its addictive nature has led to METH abuse becoming a global problem. At a cellular level, METH exerts a myriad of effects on the central and peripheral nervous systems, immune system and the gastrointestinal system. Here we present how these effects might be linked and their potential contribution to the pathogenesis of neuropsychiatric disorders. In the long term, this pathway could be targeted therapeutically to protect people from the ill effects of METH use. This model of METH use may also provide insight into how gut, nervous and immune systems might break down in other conditions that may also benefit from therapeutic intervention.

Translocation and dissemination of commensal bacteria in post-stroke infection.

Bacterial infection is highly prevalent in patients who have had a stroke. Despite the potential contribution of micro-aspiration in post-stroke pneumonia, we found that the majority of the microorganisms detected in the patients who developed infections after having a stroke were common commensal bacteria that normally reside in the intestinal tracts. In a mouse model of ischemic stroke, post-stroke infection was only observed in mice that were born and raised in specific-pathogen-free facilities; this was not seen in mice that were born and raised in germ-free facilities. Using high-throughput 16S rRNA gene amplicon sequencing and bioinformatics analyses, we provide evidence demonstrating that the source of the bacteria forming the microbial community in the lungs of post-stroke mice was indeed the host small intestine. Additionally, stroke-induced gut barrier permeability and dysfunction preceded the dissemination of orally inoculated bacteria to peripheral tissues. This study identifies a novel pathway in which stroke promotes the translocation and dissemination of selective strains of bacteria that originated from the host gut microbiota.

Mesenchymal Stem Cell Treatment of Inflammation-Induced Cancer.

Cancer development is often associated with chronic inflammation. To date, research into inflammation-induced cancer has largely focused on chemokines, cytokines, and their downstream targets. These inflammatory mediators may promote tumor growth, invasion, metastasis, and facilitate angiogenesis. However, the exact mechanisms by which inflammation promotes neoplasia remain unclear. Inflammatory bowel disease (IBD) is characterized by recurrent, idiopathic intestinal inflammation, the complications of which are potentially fatal. IBD incidence in Australia is 24.2 per 100,000 and its peak onset is in people aged 15 to 24 years. Symptoms include abdominal pain, cramps, bloody stool, and persistent diarrhoea or constipation and so seriously compromise quality of life. However, due to its unknown etiology, current treatment strategies combat the symptoms rather than the disease and are limited by inefficacy, toxicity, and adverse side-effects. IBD is also associated with an increased risk of colorectal cancer, for which treatment options are similarly limited. In recent years, there has been much interest in the therapeutic potential of mesenchymal stem cells (MSCs). However, whether MSCs suppress or promote tumor development is still contentious within the literature. Many studies indicate that MSCs exert anti-tumor effects and suppress tumor growth, whereas other studies report pro-tumor effects. Studies using MSCs as treatment for IBD have shown promising results in both animal models and human trials. However, as MSC treatment is still novel, the long-term risks remain unknown. This review aims to summarize the current literature on MSC treatment of inflammation-induced cancer, with a focus on colorectal cancer resulting from IBD.

Granzyme B promotes cytotoxic lymphocyte transmigration via basement membrane remodeling.

Granzyme B (GzmB) is a protease with a well-characterized intracellular role in targeted destruction of compromised cells by cytotoxic lymphocytes. However, GzmB also cleaves extracellular matrix components, suggesting that it influences the interplay between cytotoxic lymphocytes and their environment. Here, we show that GzmB-null effector T cells and natural killer (NK) cells exhibited a cell-autonomous homing deficit in mouse models of inflammation and Ectromelia virus infection. Intravital imaging of effector T cells in inflamed cremaster muscle venules revealed that GzmB-null cells adhered normally to the vessel wall and could extend lamellipodia through it but did not cross it efficiently. In vitro migration assays showed that active GzmB was released from migrating cytotoxic lymphocytes and enabled chemokine-driven movement through basement membranes. Finally, proteomic analysis demonstrated that GzmB cleaved basement membrane constituents. Our results highlight an important role for GzmB in expediting cytotoxic lymphocyte diapedesis via basement membrane remodeling.

Absence of SERPINB6A causes sensorineural hearing loss with multiple histopathologies in the mouse inner ear.

A homozygous mutation of SERPINB6, a gene encoding an intracellular protease inhibitor, has recently been associated with post-lingual, autosomal-recessive, nonsyndromic hearing loss in humans (DFNB91). Herein, we describe the physiological changes underlying SERPINB6 deficiency by analyzing mutant mice in which the orthologous gene is replaced by enhanced green fluorescent protein. SERPINB6A is present in the neurosensory epithelium, lateral wall, and spiral limbus of the cochlea, with highest levels in the inner and outer hair cells of the organ of Corti, cells lining the inner sulcus, and supporting cells distributed along the epithelial gap junction layer to the outer sulcus. Measurements of hearing thresholds in these mice demonstrated age-related hearing loss in all homozygous-null, but not heterozygous, mice. Hearing impairment was first detected at 3 weeks of age, affecting only high frequencies before spreading to other frequencies as the mice aged. The defect is associated with progressive cellular degeneration within the cochlea. This begins with the hair cells, then involves the primary auditory neurons, and, finally, the fibrocytes in the lateral wall. These findings establish these mutant mice as a suitable model system to elucidate how SERPINB6 deficiency causes deafness in humans.

Active and zymogen forms of granzyme B are constitutively released from cytotoxic lymphocytes in the absence of target cell engagement.

Granzyme B (GrB) plays a well-established intracellular role in cytotoxic lymphocyte (CL)-mediated killing of abnormal cells; however, emerging evidence suggests that it participates in extracellular matrix remodeling and target cell destruction through anoikis. As these processes require the release of GrB from the CL into the extracellular environment, we examined the secretion of GrB from natural killer (NK) cells and cytotoxic T lymphocytes (CTLs). We found that a proportion of GrB is constitutively secreted by both CTLs and NK cells in the absence of target cell engagement. In NK cells, the protease is primarily released in an active form through secretory granules. By contrast, T lymphocytes primarily secrete inactive GrB zymogen, bypassing the granules. The release of GrB through two routes from unconjugated CLs suggests that it functions outside the cell and may contribute to pathology in cases of immune dysregulation, such as familial hemophagocytic lymphohistiocytosis (FHL). Our findings also predict the existence of an extracellular activator of GrB.