Input and output of the central complex related to polarized light in the nervous system of the desert locust Schistocerca gregaria

Animal species from nearly all major taxa show migratory behavior, and some of these animals cover remarkable distances. Well studied examples are migratory birds like the arctic tern Sterna paradisaea that migrates from boreal and high Arctic breeding grounds to the Southern Ocean (Egevang et al., 2009). Insects also attain excellent achievements in annual migration as shown by the monarch butterfly Danaus plexippus which changes its habitat between eastern North America and central Mexico (Kyriacou, 2009). How can these animals perform such remarkable migrations? Which mechanisms underlie such a performance? Foraging ants and bees use navigational strategies similar to those of birds and mammals to reach a goal. To navigate through familiar terrain, all of these species use path integration and memories of visual landmarks (Collett & Collett, 2002). During path integration, an animal permanently updates a homing vector resulting from all angular and translational movements so that it can always take a direct path back to its starting point (Collett & Collett, 2000). To compute resulting novel routes out of several single homing flights, bees use a map-like navigation strategy that allows targetoriented decisions at any place and toward any intended location within the familiar terrain (Menzel et al., 2006). These mechanisms are used for near-range navigation, termed as "homing", rather than for long-distance navigation tasks. Animals that navigate through unknown space are forced to use cues of a global nature, such as the geomagnetic field, the stars, and cues related to the position of the sun (Frost & Mouritsen, 2006). Like diverse marine animals, e.g. marine turtles, lobsters, and molluscs, the green sea-turtle Chelonia mydas has a magnetic map sense for navigation to specific targets (Cain et al., 2005; Lohmann et al., 2004). Many diurnal species use a time-compensated sun-compass, other sky compass cues like polarized light, or stars for steering toward distant targets (Wehner, 1984; Homberg, 2004; Frost & Mouritsen, 2006)

JAK/STAT Signalling in Huntington's Disease Immune Cells.

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin (HTT) gene. Both central and peripheral innate immune activation have been described as features of the disease. Isolated human HD monocytes have been shown to produce more cytokines upon LPS stimulation compared to control monocytes. Understanding alterations in the signalling cascades responsible and activated by this increase in pro-inflammatory cytokine production is crucial in understanding the molecular basis of this phenomenon. Here we investigated the signalling cascade most commonly activated by pro-inflammatory cytokines such as IL-6 - the JAK/STAT signalling cascade. Using flow cytometry, we show that one out of three key transcription factors activated by JAK/STAT signalling is altered in primary human HD innate immune cells, suggesting that this pathway may only play a minor, additive role in the immune cell dysfunction in HD

Laquinimod dampens hyperactive cytokine production in Huntington's disease patient myeloid cells.

Huntington's disease (HD) is a neurodegenerative condition characterized by pathology in the brain and peripheral tissues. Hyperactivity of the innate immune system, due in part to NFκB pathway dysregulation, is an early and active component of HD. Evidence suggests targeting immune disruption may slow disease progression. Laquinimod is an orally active immunomodulator that down-regulates proinflammatory cytokine production in peripheral blood mononuclear cells, and in the brain down-regulates astrocytic and microglial activation by modulating NFκB signalling. Laquinimod had beneficial effects on inflammation, brain atrophy and disease progression in multiple sclerosis (MS) in two phase III clinical trials. This study investigated the effects of laquinimod on hyperactive proinflammatory cytokine release and NFκB signalling in HD patient myeloid cell cultures. Monocytes from manifest (manHD) and pre-manifest (preHD) HD gene carriers and healthy volunteers (HV) were treated with laquinimod and stimulated with lipopolysaccharide. After 24 h pre-treatment with 5 μM laquinimod, manHD monocytes released lower levels of IL-1β, IL-5, IL-8, IL-10, IL-13 and TNFα in response to stimulation. PreHD monocytes released lower levels of IL-8, IL-10 and IL-13, with no reduction observed in HV monocytes. The effects of laquinimod on dysfunctional NFκB signalling in HD was assessed by inhibitor of kappa B (IκB) degradation kinetics, nuclear translocation of NFκB and interactions between IκB kinase (IKK) and HTT, in HD myeloid cells. No differences were observed between laquinimod-treated and untreated conditions. These results provide evidence that laquinimod dampens hyper-reactive cytokine release from manHD and preHD monocytes, with a much reduced effect on HV monocytes. Evidence suggests targeting CNS and peripheral immune disruption may slow Huntington's disease (HD) neurodegenerative processes. The effects of laquinimod, an orally active immunomodulator, on hyperactive cytokine release and dysfunctional NFκB signalling in stimulated myeloid cell cultures from pre-manifest and manifest HD gene carriers and healthy volunteers were investigated. Laquinimod dampened cytokine release but did not impact NFκB signalling. Read the Editorial Highlight for this article on page 670

RNA-Seq of Huntington's disease patient myeloid cells reveals innate transcriptional dysregulation associated with proinflammatory pathway activation

Innate immune activation beyond the central nervous system is emerging as a vital component of the pathogenesis of neurodegeneration. Huntington’s disease (HD) is a fatal neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin gene. The systemic innate immune system is thought to act as a modifier of disease progression; however, the molecular mechanisms remain only partially understood. Here we use RNA-sequencing to perform whole transcriptome analysis of primary monocytes from thirty manifest HD patients and thirty-three control subjects, cultured with and without a proinflammatory stimulus. In contrast with previous studies that have required stimulation to elicit phenotypic abnormalities, we demonstrate significant transcriptional differences in HD monocytes in their basal, unstimulated state. This includes previously undetected increased resting expression of genes encoding numerous proinflammatory cytokines, such as IL6. Further pathway analysis revealed widespread resting enrichment of proinflammatory functional gene sets, while upstream regulator analysis coupled with Western blotting suggests that abnormal basal activation of the NFOEB pathway plays a key role in mediating these transcriptional changes. That HD myeloid cells have a proinflammatory phenotype in the absence of stimulation is consistent with a priming effect of mutant huntingtin, whereby basal dysfunction leads to an exaggerated inflammatory response once a stimulus is encountered. These data advance our understanding of mutant huntingtin pathogenesis, establish resting myeloid cells as a key source of HD immune dysfunction, and further demonstrate the importance of systemic immunity in the potential treatment of HD and the wider study of neurodegeneration

The Role of Dietary Fiber in Rheumatoid Arthritis Patients: A Feasibility Study

Short-chain fatty acids are microbial metabolites that have been shown to be key regulators of the gut–joint axis in animal models. In humans, microbial dysbiosis was observed in rheumatoid arthritis (RA) patients as well as in those at-risk to develop RA, and is thought to be an environmental trigger for the development of clinical disease. At the same time, diet has a proven impact on maintaining intestinal microbial homeostasis. Given this association, we performed a feasibility study in RA patients using high-fiber dietary supplementation with the objective to restore microbial homeostasis and promote the secretion of beneficial immunomodulatory microbial metabolites. RA patients (n = 36) under routine care received daily high-fiber bars or cereals for 28 days. Clinical assessments and laboratory analysis of immune parameters in blood and stool samples from RA patients were done before and after the high-fiber dietary supplementation. We observed an increase in circulating regulatory T cell numbers, favorable Th1/Th17 ratios, as well as decreased markers of bone erosion in RA patients after 28 days of dietary intervention. Furthermore, patient-related outcomes of RA improved. Based on these results, we conclude that controlled clinical studies of high-fiber dietary interventions could be a viable approach to supplement or complement current pharmacological treatment strategies

Hemoadsorption in ‘liver indication’: analysis of 109 patients’ data from the CytoSorb international registry

Background: Our aim is to report the results of the ‘liver indication’ subset of patients in the CytoSorb International Registry. Methods: Structured data were recorded. Treatment characteristics and changes from T1 (start of hemoadsorption) to T2 (termination) were evaluated with a special focus on bilirubin, C-reactive protein, procalcitonin, interleukin-6, platelet levels, SOFA scores, mortality, and subjective assessment by the attending physicians. Results: Until January 2021, from the total 1434 patients, 109 (age: 49.2 ± 17.1 years, 57.8% males) received treatment for hyperbilirubinemia. APACHE II-predicted mortality was 49.6 ± 26.8%. In the study, 91% of patients were alive at the termination of hemoadsorption and improvement was observed by the physicians in 75 cases. Overall, 65 (59.6%) patients died in the hospital, and 60 (55.0%) died in the ICU. Patients received a median of two treatments for a median of 43 h (interquartile range: 24–72 h) in total. Serum bilirubin levels reduced significantly to −4.6 (95% CI: −6.329 to −2.8) mg/dL. Thrombocytopenia was reported in four patients as an adverse event. Conclusions: We report the largest case series on hemoadsorption for ‘liver indication’ from the CytoSorb International Registry. The finding of significant bilirubin removal observed in our study could have substantial impact in designing and executing further studies on the effects of hemoadsorption in liver dysfunction, which are certainly warranted

HTT-lowering reverses Huntington's disease immune dysfunction caused by NFκB pathway dysregulation

The peripheral immune response is altered in Huntington's disease, but the underlying mechanisms are unclear. Using RNA interference to lower huntingtin levels in leucocytes from patients, Träger et al. reverse disease-associated phenotypes including cytokine elevation and transcriptional dysregulation, and argue for a direct effect of mutant huntingtin on NFκΒ signallin

The Immune Response to Melanoma Is Limited by Thymic Selection of Self-Antigens

The expression of melanoma-associated antigens (MAA) being limited to normal melanocytes and melanomas, MAAs are ideal targets for immunotherapy and melanoma vaccines. As MAAs are derived from self, immune responses to these may be limited by thymic tolerance. The extent to which self-tolerance prevents efficient immune responses to MAAs remains unknown. The autoimmune regulator (AIRE) controls the expression of tissue-specific self-antigens in thymic epithelial cells (TECs). The level of antigens expressed in the TECs determines the fate of auto-reactive thymocytes. Deficiency in AIRE leads in both humans (APECED patients) and mice to enlarged autoreactive immune repertoires. Here we show increased IgG levels to melanoma cells in APECED patients correlating with autoimmune skin features. Similarly, the enlarged T cell repertoire in AIRE−/− mice enables them to mount anti-MAA and anti-melanoma responses as shown by increased anti-melanoma antibodies, and enhanced CD4+ and MAA-specific CD8+ T cell responses after melanoma challenge. We show that thymic expression of gp100 is under the control of AIRE, leading to increased gp100-specific CD8+ T cell frequencies in AIRE−/− mice. TRP-2 (tyrosinase-related protein), on the other hand, is absent from TECs and consequently TRP-2 specific CD8+ T cells were found in both AIRE−/− and AIRE+/+ mice. This study emphasizes the importance of investigating thymic expression of self-antigens prior to their inclusion in vaccination and immunotherapy strategies

KEAP1-modifying small molecule reveals muted NRF2 signaling responses in neural stem cells from Huntington's disease patients

The activity of the transcription factor nuclear factor-erythroid 2 p45-derived factor 2 (NRF2) is orchestrated and amplified through enhanced transcription of antioxidant and antiinflammatory target genes. The present study has characterized a triazole-containing inducer of NRF2 and elucidated the mechanism by which this molecule activates NRF2 signaling. In a highly selective manner, the compound covalently modifies a critical stress-sensor cysteine (C151) of the E3 ligase substrate adaptor protein Kelch-like ECH-associated protein 1 (KEAP1), the primary negative regulator of NRF2. We further used this inducer to probe the functional consequences of selective activation of NRF2 signaling in Huntington's disease (HD) mouse and human model systems. Surprisingly, we discovered a muted NRF2 activation response in human HD neural stem cells, which was restored by genetic correction of the disease-causing mutation. In contrast, selective activation of NRF2 signaling potently repressed the release of the proinflammatory cytokine IL-6 in primary mouse HD and WT microglia and astrocytes. Moreover, in primary monocytes from HD patients and healthy subjects, NRF2 induction repressed expression of the proinflammatory cytokines IL-1, IL-6, IL-8, and TNFα. Together, our results demonstrate a multifaceted protective potential of NRF2 signaling in key cell types relevant to HD pathology

Input and output of the central complex related to polarized light in the nervous system of the desert locust Schistocerca gregaria

Animal species from nearly all major taxa show migratory behavior, and some of these animals cover remarkable distances. Well studied examples are migratory birds like the arctic tern Sterna paradisaea that migrates from boreal and high Arctic breeding grounds to the Southern Ocean (Egevang et al., 2009). Insects also attain excellent achievements in annual migration as shown by the monarch butterfly Danaus plexippus which changes its habitat between eastern North America and central Mexico (Kyriacou, 2009). How can these animals perform such remarkable migrations? Which mechanisms underlie such a performance? Foraging ants and bees use navigational strategies similar to those of birds and mammals to reach a goal. To navigate through familiar terrain, all of these species use path integration and memories of visual landmarks (Collett & Collett, 2002). During path integration, an animal permanently updates a homing vector resulting from all angular and translational movements so that it can always take a direct path back to its starting point (Collett & Collett, 2000). To compute resulting novel routes out of several single homing flights, bees use a map-like navigation strategy that allows targetoriented decisions at any place and toward any intended location within the familiar terrain (Menzel et al., 2006). These mechanisms are used for near-range navigation, termed as "homing", rather than for long-distance navigation tasks. Animals that navigate through unknown space are forced to use cues of a global nature, such as the geomagnetic field, the stars, and cues related to the position of the sun (Frost & Mouritsen, 2006). Like diverse marine animals, e.g. marine turtles, lobsters, and molluscs, the green sea-turtle Chelonia mydas has a magnetic map sense for navigation to specific targets (Cain et al., 2005; Lohmann et al., 2004). Many diurnal species use a time-compensated sun-compass, other sky compass cues like polarized light, or stars for steering toward distant targets (Wehner, 1984; Homberg, 2004; Frost & Mouritsen, 2006)