Reciprocal modulation of helper Th1 and Th17 cells by the β2-adrenergic receptor agonist drug terbutaline

TH17/Treg lymphocyte balance is regulated by beta adrenergic and cAMP signaling

BACKGROUND

Post-traumatic stress disorder (PTSD) is a debilitating psychological disorder that also presents with neuroimmune irregularities. Patients display elevated sympathetic tone and are at an increased risk of developing secondary autoimmune diseases. Previously, using a mouse model of repeated social defeat stress (RSDS) that recapitulates certain features of PTSD, we demonstrated that elimination of sympathetic signaling to T-lymphocytes specifically limited their ability to produce pro-inflammatory interleukin 17A (IL-17A); a cytokine implicated in the development of many autoimmune disorders. However, the mechanism linking sympathetic signaling to T-lymphocyte IL-17A production remained unclear.

METHODS

Using a modified version of RSDS that allows for both males and females, as well as ex vivo models of T-lymphocyte polarization, we assessed the impact and mechanism of adrenergic receptor blockade (genetically and pharmacologically) and catecholamine depletion on T-lymphocyte differentiation to IL-17A-producing subtypes (i.e., TH17).

RESULTS

Only pharmacological inhibition of the beta 1 and 2 adrenergic receptors (β1/2) significantly decreased circulating IL-17A levels after RSDS, but did not impact other pro-inflammatory cytokines (e.g.,IL-6, TNF-α, and IL-10). This finding was confirmed using RSDS with both global β1/2 receptor knock-out mice, as well as by adoptively transferring β1/2 knock-out T-lymphocytes into immunodeficient hosts. Ex vivo polarized T-lymphocytes produced significantly less IL-17A with the blockade of β1/2 signaling, even in the absence of exogenous sympathetic neurotransmitter supplementation, which suggested T-lymphocyte-produced catecholamines may be involved in IL-17A production. Furthermore, cyclic AMP (cAMP) was demonstrated to be mechanistically involved in driving IL-17A production in T-lymphocytes, and amplifying cAMP signaling could restore IL-17A deficits caused by the absence of β1/2 signaling. Last, removal of β1/2 and cAMP signaling, even in IL-17A polarizing conditions, promoted regulatory T-lymphocyte (Treg) polarization, suggesting adrenergic signaling plays a role in the switching between pro- and anti-inflammatory T-lymphocyte subtypes.

CONCLUSIONS

Our data depict a novel role for β1/2 adrenergic and cAMP signaling in the balance of TH17/Treg lymphocytes. These findings provide a new target for pharmacological therapy in both psychiatric and autoimmune diseases associated with IL-17A-related pathology.

Microbiota-immune-brain interactions: A new vision in the understanding of periodontal health and disease

This review highlights the significance of interactions between the microbiota, immune system, nervous and hormonal systems, and the brain on periodontal health and disease. Microorganisms in the microbiota, immune cells, and neurons communicate via homeostatic nervous and hormonal systems, regulating vital body functions. By modulating pro-inflammatory and anti-inflammatory adaptive immune responses, these systems control the composition and number of microorganisms in the microbiota. The strength of these brain-controlled responses is genetically determined but is sensitive to early childhood stressors, which can permanently alter their responsiveness via epigenetic mechanisms, and to adult stressors, causing temporary changes. Clinical evidence and research with humans and animal models indicate that factors linked to severe periodontitis enhance the responsiveness of these homeostatic systems, leading to persistent hyperactivation. This weakens the immune defense against invasive symbiotic microorganisms (pathobionts) while strengthening the defense against non-invasive symbionts at the gingival margin. The result is an increased gingival tissue load of pathobionts, including Gram-negative bacteria, followed by an excessive innate immune response, which prevents infection but simultaneously destroys gingival and periodontal tissues. Thus, the balance between pro-inflammatory and anti-inflammatory adaptive immunity is crucial in controlling the microbiota, and the responsiveness of brain-controlled homeostatic systems determines periodontal health.

Beta-adrenergic signaling and T-lymphocyte-produced catecholamines are necessary for interleukin 17A synthesis

Background

Post-traumatic stress disorder (PTSD) is a debilitating psychological disorder that also presents with neuroimmune irregularities. Patients display elevated sympathetic tone and are at an increased risk of developing secondary autoimmune diseases. Previously, using a preclinical model of PTSD, we demonstrated that elimination of sympathetic signaling to T-lymphocytes specifically limited their ability to produce pro-inflammatory interleukin 17A (IL-17A); a cytokine implicated in the development of many autoimmune disorders. However, the mechanism linking sympathetic signaling to T-lymphocyte IL-17A production remained unclear.

Methods

Using a modified version of repeated social defeat stress (RSDS) that allows for both males and females, we assessed the impact of adrenergic receptor blockade (genetically and pharmacologically) and catecholamine depletion on T-lymphocyte IL-17A generation. Additionally, we explored the impact of adrenergic signaling and T-lymphocyte-produced catecholamines on both CD4+ and CD8+ T-lymphocytes polarized to IL-17A-producing phenotypes ex vivo.

Results

Only pharmacological inhibition of the beta 1 and 2 adrenergic receptors (β1/2) significantly decreased circulating IL-17A levels after RSDS, but did not impact other pro-inflammatory cytokines (e.g., IL-6, TNF-α, and IL-10). This finding was confirmed using RSDS with both global β1/2 receptor knock-out mice, as well as by adoptively transferring β1/2 knock-out T-lymphocytes into immunodeficient hosts. Furthermore, ex vivo polarized T-lymphocytes produced significantly less IL-17A with the blockade of β1/2 signaling, even in the absence of exogenous sympathetic neurotransmitter supplementation, which suggested T-lymphocyte-produced catecholamines may be involved in IL-17A production. Indeed, pharmacological depletion of catecholamines both in vivo and ex vivo abrogated T-lymphocyte IL-17A production demonstrating the importance of immune-generated neurotransmission in pro-inflammatory cytokine generation.

Conclusions

Our data depict a novel role for β1/2 adrenergic receptors and autologous catecholamine signaling during T-lymphocyte IL-17A production. These findings provide a new target for pharmacological therapy in both psychiatric and autoimmune diseases associated with IL-17A-related pathology.

Immunopathogenesis of multiple sclerosis: molecular and cellular mechanisms and new immunotherapeutic approaches

BACKGROUND

Multiple sclerosis (MS) is a central nervous system (CNS) demyelinating autoimmune disease with increasing global prevalence. It predominantly affects females, especially those of European descent. The interplay between environmental factors and genetic predisposition plays a crucial role in MS etiopathogenesis.

METHODS

We searched recent relevant literature on reputable databases, which include, PubMed, Embase, Web of Science, Scopus, and ScienceDirect using the following keywords: multiple sclerosis, pathogenesis, autoimmunity, demyelination, therapy, and immunotherapy.

RESULTS

Various animal models have been employed to investigate the MS etiopathogenesis and therapeutics. Autoreactive T cells within the CNS recruit myeloid cells through chemokine expression, leading to the secretion of inflammatory cytokines driving the MS pathogenesis, resulting in demyelination, gliosis, and axonal loss. Key players include T cell lymphocytes (CD4+ and CD8+), B cells, and neutrophils. Signaling dysregulation in inflammatory pathways and the immunogenetic basis of MS are essential considerations for any successful therapy to MS. Data indicates that B cells and neutrophils also have significant roles in MS, despite the common belief that T cells are essential. High neutrophil-to-lymphocyte ratios correlate with MS severity, indicating their contribution to disease progression. Dysregulated signaling pathways further exacerbate MS progression.

CONCLUSION

MS remains incurable, but disease-modifying therapies, monoclonal antibodies, and immunomodulatory drugs offer hope for patients. Research on the immunogenetics and immunoregulatory functions of gut microbiota is continuing to provide light on possible treatment avenues. Understanding the complex interplay between genetic predisposition, environmental factors, and immune dysregulation is critical for developing effective treatments for MS.

The β2-adrenergic receptor agonist terbutaline upregulates T helper-17 cells in a protein kinase A-dependent manner

BACKGROUND

T helper 17 (Th17) cells produce IL-17A cytokine and can exacerbate autoimmune diseases and asthma. The β2 adrenergic receptor is a g protein-coupled receptor that induces cAMP second messenger pathways. We tested the hypothesis that terbutaline, a β2-adrenergic receptor-specific agonist, promotes IL-17 secretion by memory Th17 cells in a cAMP and PKA-dependent manner.

METHODS

Venous peripheral blood mononuclear cells (PBMC) from healthy human participants were activated with anti-CD3 and anti-CD28 antibodies. Secreted IL-17A was measured by enzyme linked immunosorbent assay, intracellular IL-17A, and RORγ were measured using flow cytometry, and RORC by qPCR. Memory CD3+CD4+CD45RA-CD45RO+ T cells were obtained by immunomagnetic negative selection and activated with tri-antibody complex CD3/CD28/CD2. Secreted IL-17A, intracellular IL-17A, RORC were measured, and phosphorylated-serine133-CREB was measured by western blotting memory Th cells.

RESULTS

Terbutaline increased IL-17A (p < 0.001), IL-17A+ cells (p < 0.05), and RORC in activated PBMC and memory Th cells. The PKA inhibitors H89 (p < 0.001) and Rp-cAMP (p < 0.01) abrogated the effects of terbutaline on IL-17A secretion in PBMC and memory T cells. Rolipram increased IL-17A (p < 0.01) to a similar extent as terbutaline. P-Ser133-CREB was increased by terbutaline (p < 0.05) in memory T cells.

CONCLUSION

Terbutaline augments memory Th17 cells in lymphocytes from healthy participants. This could exacerbate autoimmune diseases or asthma, in cases where Th17 cells are considered to be pro-inflammatory.

Adrenoceptors as potential target for add-on immunomodulatory therapy in multiple sclerosis

This review summarizes recent findings related to the role of the sympathetic nervous system (SNS) in pathogenesis of multiple sclerosis (MS) and its commonly used experimental model - experimental autoimmune encephalomyelitis (EAE). They indicate that noradrenaline, the key end-point mediator of the SNS, acting through β-adrenoceptor, has a contributory role in the early stages of MS/EAE development. This stage is characterized by the SNS hyperactivity (increased release of noradrenaline) reflecting the net effect of different factors, such as the disease-associated inflammation, stress, vitamin D hypovitaminosis, Epstein-Barr virus infection and dysbiosis. Thus, the administration of propranolol, a non-selective β-adrenoceptor blocker, readily crossing the blood-brain barrier, to experimental rats before the autoimmune challenge and in the early (preclinical/prodromal) phase of the disease mitigates EAE severity. This phenomenon has been ascribed to the alleviation of neuroinflammation (due to attenuation of primarily microglial activation/proinflammatory functions) and the diminution of the magnitude of the primary CD4+ T-cell autoimmune response (the effect associated with impaired autoantigen uptake by antigen presenting cells and their migration into draining lymph nodes). The former is partly related to breaking of the catecholamine-dependent self-amplifying microglial feed-forward loop and the positive feedback loop between microglia and the SNS, leading to down-regulation of the SNS hyperactivity and its enhancing influence on microglial activation/proinflammatory functions and the magnitude of autoimmune response. The effects of propranolol are shown to be more prominent in male EAE animals, the phenomenon important as males (like men) are likely to develop clinically more severe disease. Thus, these findings could serve as a firm scientific background for formulation of a new sex-specific immune-intervention strategy for the early phases of MS (characterized by the SNS hyperactivity) exploiting anti-(neuro)inflammatory and immunomodulatory properties of propranolol and other relatively cheap and safe adrenergic drugs with similar therapeutic profile.

Peripheral Beta-2 Adrenergic Receptors Mediate the Sympathetic Efferent Activation from Central Nervous System to Splenocytes in a Mouse Model of Fibromyalgia

Abnormalities in the peripheral immune system are involved in the pathophysiology of fibromyalgia, although their contribution to the painful symptoms remains unknown. Our previous study reported the ability of splenocytes to develop pain-like behavior and an association between the central nervous system (CNS) and splenocytes. Since the spleen is directly innervated by sympathetic nerves, this study aimed to examine whether adrenergic receptors are necessary for pain development or maintenance using an acid saline-induced generalized pain (AcGP) model (an experimental model of fibromyalgia) and whether the activation of these receptors is also essential for pain reproduction by the adoptive transfer of AcGP splenocytes. The administration of selective β2-blockers, including one with only peripheral action, prevented the development but did not reverse the maintenance of pain-like behavior in acid saline-treated C57BL/6J mice. Neither a selective α1-blocker nor an anticholinergic drug affects the development of pain-like behavior. Furthermore, β2-blockade in donor AcGP mice eliminated pain reproduction in recipient mice injected with AcGP splenocytes. These results suggest that peripheral β2-adrenergic receptors play an important role in the efferent pathway from the CNS to splenocytes in pain development.

Th17-cells in depression: Implication in multiple sclerosis

Depression is one of the most common neuropsychological symptoms of multiple sclerosis. However, in addition to mood disorder, depression can also influence on multiple sclerosis course. The mechanism of this dependence is not fully understood. The recent studies suggest the possible common immune mechanisms in the pathogenesis of depression and multiple sclerosis. In particular, it was shown that along with biogenic amines disturbance, neuroinflammation also play an important role in the pathogenesis of depression. Significant attention is drawn to Th17-cells subsets, which are considered as critical players in the pathogenesis of inflammatory diseases of the central nervous system, including multiple sclerosis. This brief report reviews the literature data on the role of neuroinflammation in the reciprocal influence of multiple sclerosis and depression with focus on Th17-cells, which may underlie pathogenetic mechanisms of both this diseases.

Stress hormone signaling inhibits Th1 polarization in a CD4 T-cell-intrinsic manner via mTORC1 and the circadian gene PER1

Stress hormones are believed to skew the CD4 T‐cell differentiation towards a Th2 response via a T‐cell‐extrinsic mechanism. Using isolated primary human naïve and memory CD4 T cells, here we show that both adrenergic‐ and glucocorticoid‐mediated stress signalling pathways play a CD4 naïve T‐cell‐intrinsic role in regulating the Th1/Th2 differentiation balance. Both stress hormones reduced the Th1 programme and cytokine production by inhibiting mTORC1 signalling via two parallel mechanisms. Stress hormone signalling inhibited mTORC1 in naïve CD4 T cells (1) by affecting the PI3K/AKT pathway and (2) by regulating the expression of the circadian rhythm gene, period circadian regulator 1 (PER1). Both stress hormones induced the expression of PER1, which inhibited mTORC1 signalling, thus reducing Th1 differentiation. This previously unrecognized cell‐autonomous mechanism connects stress hormone signalling with CD4 T‐cell differentiation via mTORC1 and a specific circadian clock gene, namely PER1.

The Dual Role of the β2-Adrenoreceptor in the Modulation of IL-17 and IFN-γ Production by T Cells in Multiple Sclerosis

Norepinephrine is a neurotransmitter that also has an immunomodulatory effect and is involved in multiple sclerosis (MS) pathogenesis. This study aimed to clarify the role of the β₂-adrenoreceptor in the norepinephrine-mediated modulation of interleukin-17 (IL-17) and interferon-γ (IFN-γ) production, which play a critical pathogenetic role in MS. CD4⁺ T cells obtained from twenty-five relapsing-remitting MS patients and sixteen healthy subjects were cultured ex vivo with norepinephrine and/or β₂-adrenoreceptor antagonist or agonist, followed by a cytokine production analysis using ELISA. Norepinephrine suppressed IL-17 and IFN-γ production by the anti-CD3/anti-CD28-microbead-stimulated CD4⁺ T cells in both groups. Blockade of the β₂-adrenoreceptor with the specific antagonist ICI 118.551 enhanced norepinephrine-mediated IL-17 suppression but decreased its inhibitory effect on IFN-γ production in MS patients. In contrast, the β₂-adrenoreceptor agonist formoterol did not influence norepinephrine’s inhibitory effect on cytokine production in both groups. The blockade of the β₂-adrenoreceptor, even in the absence of exogenous norepinephrine, suppressed IL-17 production but did not influence IFN-γ production in both groups. Conversely, β₂-adrenoreceptor activation by formoterol decreased IFN-γ production and did not affect IL-17 production in both groups. These data illustrate the inhibitory effect of norepinephrine on IL-17 and IFN-γ production by CD4⁺ T cells in MS. The inhibitory effect of norepinephrine on IFN-γ production by CD4⁺ T cells in MS could be mediated via β₂-adrenoreceptor activation.

Endogenously produced catecholamines improve the regulatory function of TLR9-activated B cells

The sympathetic nervous system (SNS) contributes to immune balance by promoting anti-inflammatory B cells. However, whether B cells possess a self-regulating mechanism by which they modulate regulatory B cell (Breg) function is not well understood. In this study, we investigated the ability of B cells to synthesize their own catecholamines upon stimulation with different B cell activators and found that expression of the enzyme tyrosine hydroxylase (TH), required to generate catecholamines, is up-regulated by Toll-like receptor (TLR)9. This TLR9-dependent expression of TH correlated with up-regulation of adrenergic receptors (ADRs), enhanced interleukin (IL)-10 production, and overexpression of the co-inhibitory ligands programmed death ligand 1 (PD-L1) and Fas ligand (FasL). Moreover, concomitant stimulation of ß1-3-ADRs together with a B cell receptor (BCR)/TLR9 stimulus clearly enhances the anti-inflammatory potential of Bregs to suppress CD4 T cells, a crucial population in the pathogenesis of autoimmune diseases, like rheumatoid arthritis (RA). Furthermore, TH up-regulation was also demonstrated in B cells during the course of collagen-induced arthritis (CIA), a mouse model for the investigation of RA. In conclusion, our data show that B cells possess an autonomous mechanism to modulate their regulatory function in an autocrine and/or paracrine manner. These findings help to better understand the function of B cells in the regulation of autoimmune diseases and the interplay of SNS.

The sympathetic nervous system produces neurotransmitters such as catecholamines which contribute to immune balance by promoting anti-inflammatory B cells. This study shows that mouse B cells can themselves synthesize, sense, and transport catecholamines, which in turn modulate regulatory B cell function in an autocrine and/or paracrine manner to suppress T cell proliferation.

Modulation of IL-17A and IFNγ by β2-adrenergic agonist terbutaline and inverse-agonist nebivolol, influence of ADRB2 polymorphisms

<abstract><sec> <title>Background</title> <p>Upon activation, helper T (Th) cells produce cytokines such as IL-17A and IFNγ, which may exacerbate inflammatory disease and disorders. Adrenergic drugs are emerging as immunomodulatory agents to treat pro-inflammatory diseases, but their function is not completely understood. Th Cells express the β2-adrenergic receptor (β2AR) that is encoded by <italic>ADRB2</italic>. Agonists of the β2AR decrease IFNγ but can increase IL-17A from Th cells. We compared a β2AR agonist to an inverse-agonist, and assessed the influence of <italic>ADRB2</italic> polymorphisms on IL-17A and IFNγ responses.</p> </sec><sec> <title>Methods</title> <p>Peripheral blood mononuclear cells (PBMCs) from venous blood of healthy human participants were cultured with T cell activators anti-CD3 and anti-CD28 antibodies. Terbutaline, a β2AR agonist or nebivolol, a β1AR antagonist and β2AR inverse-agonist, were added <italic>in vitro</italic>. Cytokines IL-17A and IFNγ were measured using enzyme-linked immunosorbent assay. Genomic <italic>ADRB2</italic> and its immediate upstream region were sequenced using Sanger's method. Cytokine response to drug was analyzed based on <italic>ADRB2</italic> polymorphisms.</p> </sec><sec> <title>Results</title> <p>Terbutaline consistently inhibited IFNγ from activated PBMC samples. In contrast, it increased IL-17A in PBMC homozygous for Gly16 codon of <italic>ADRB2</italic>. Nebivolol inhibited IL-17A and IFNγ from activated Th cells. When applied to activated-PBMCs, nebivolol inhibited IL-17A but did not significantly inhibit IFNγ although a trend was observed. The ability of nebivolol to inhibit IL-17A was attenuated by a β2AR-specific antagonist. Cellular proliferation and viability was not significantly changed by nebivolol. Nebivolol suppressed IL-17A in all of the samples regardless of <italic>ADRB2</italic> polymorphisms.</p> </sec><sec> <title>Conclusions</title> <p>This data demonstrates that terbutaline inhibited IFNγ, however, it increased IL-17A in samples with the common Gly16 polymorphism of <italic>ADRB2</italic>. Nebivolol inhibited IL-17A regardless of <italic>ADRB2</italic> polymorphisms. Thus, nebivolol is a strong candidate for treating inflammatory diseases or disorders where IL-17A exacerbates symptoms.</p> </sec></abstract>

CRID3, a blocker of apoptosis associated speck like protein containing a card, ameliorates murine spinal cord injury by improving local immune microenvironment

Background

After spinal cord injury (SCI), destructive immune cell subsets are dominant in the local microenvironment, which are the important mechanism of injury. Studies have shown that inflammasomes play an important role in the inflammation following SCI, and apoptosis-associated speck-like protein containing a card (ASC) is the adaptor protein shared by inflammasomes. Therefore, we speculated that inhibiting ASC may improve the local microenvironment of injured spinal cord. Here, CRID3, a blocker of ASC oligomerization, was used to study its effect on the local microenvironment and the possible role in neuroprotection following SCI.

Methods

Murine SCI model was created using an Infinite Horizon impactor at T9 vertebral level with a force of 50 kdynes and CRID3 (50 mg/kg) was intraperitoneally injected following injury. ASC and its downstream molecules in inflammasome signaling pathway were measured by western blot. The immune cell subsets were detected by immunohistofluorescence (IHF) and flow cytometry (FCM). The spinal cord fibrosis area, neuron survival, myelin preservation, and functional recovery were assessed.

Results

Following SCI, CRID3 administration inhibited inflammasome-related ASC and caspase-1, IL-1β, and IL-18 activation, which consequently suppressed M1 microglia, Th1 and Th1Th17 differentiation, and increased M2 microglia and Th2 differentiation. Accordingly, the improved histology and behavior have also been found.

Conclusions

CRID3 may ameliorate murine SCI by inhibiting inflammasome activation, reducing proinflammatory factor production, restoring immune cell subset balance, and improving local immune microenvironment, and early administration may be a promising therapeutic strategy for SCI.

Sympathetic improvement of cancer vaccine efficacy

The link between stress, other psychological factors and response to cancer, or even the cancer incidence and metastasis, is well established. The inhibition of β-Adrenergic receptors (β-AR) using β-blockers was demonstrated to have an inhibitory effect on cancer recurrence. Direct effects on the stress-induced suppression of anti-tumor immune responses were also shown. In a recent issue of Cancer Immunology Research, Daher and colleagues studied the molecular mechanism behind this protective effect in the context of cancer vaccination. They provided evidence that the β-AR signaling affected the priming of naïve CD8 + T cells in their myeloma model, rather than effector CD8 + T cells which downregulated the expression of β-AR after activation and became insensitive to such signaling. Blocking the β-adrenergic signaling during vaccination led to increased expansion and effector functions of antigen-specific CD8 + T cells and reduced tumor growth. This has implications for the clinical use of β-blockers as adjuvants to enhance cancer vaccination and other types of immunotherapy.

Role of the End-Point Mediators of Sympathoadrenal and Sympathoneural Stress Axes in the Pathogenesis of Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis

The role of stress effector systems in the initiation and progression of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), the most commonly used experimental model of MS, has strongly been suggested. To corroborate this notion, alterations in activity of the sympathoadrenal and sympathoneural axes of sympathoadrenal system (a major communication pathway between the central nervous system and the immune system), mirrored in altered release of their end-point mediators (adrenaline and noradrenaline, respectively), are shown to precede (in MS) and/or occur during development of MS and EAE in response to immune cell activation (in early phase of disease) and disease-related damage of sympathoadrenal system neurons and their projections (in late phase of disease). To add to the complexity, innate immunity cells and T-lymphocytes synthesize noradrenaline that may be implicated in a local autocrine/paracrine self-amplifying feed-forward loop to enhance myeloid-cell synthesis of proinflammatory cytokines and inflammatory injury. Furthermore, experimental manipulations targeting noradrenaline/adrenaline action are shown to influence clinical outcome of EAE, in a disease phase-specific manner. This is partly related to the fact that virtually all types of cells involved in the instigation and progression of autoimmune inflammation and target tissue damage in EAE/MS express functional adrenoceptors. Although catecholamines exert majority of immunomodulatory effects through β₂-adrenoceptor, a role for α-adrenoceptors in EAE pathogenesis has also been indicated. In this review, we summarize all aforementioned aspects of immunopathogenetic action of catecholamines in EAE/MS as possibly important for designing new strategies targeting their action to prevent/mitigate autoimmune neuroinflammation and tissue damage.

Bidirectional Role of β2-Adrenergic Receptor in Autoimmune Diseases

Disorder of the sympathetic nervous system (SNS) is closely related to the pathogenesis of various autoimmune diseases (ADs). Catecholamine triggered beta2-adrenergic receptor (β2-AR) signaling is important in creating a bidirectional response in the progression of ADs due to factors including diverse expression patterns, single nucleotide polymorphisms (SNPs), biased signals, and desensitization of β2-AR, as well as different subtypes of Gα binding to β2-AR. In this review, we summarize the actions of β2-AR signaling in regulating the functions of immunocytes and in the pathogenesis of ADs, and the application of β2-AR agonists or antagonists in treating major types of ADs is also discussed. We suggest that restoring the immune balance via a soft regulation of the expression or activation of β2-AR is one of the promising therapeutic strategies for systematic ADs.

Helper CD4 T cells expressing granzyme B cause glial fibrillary acidic protein fragmentation in astrocytes in an MHCII-independent manner

During inflammatory processes of the central nervous system, helper T cells have the capacity to cross the blood-brain barrier and injure or kill neural cells through cytotoxic mechanisms. Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is part of the astrocyte cytoskeleton that can become fragmented in neuroinflammatory conditions. The mechanism of action by which helper T cells with cytotoxic properties injure astrocytes is not completely understood. Primary human astrocytes were obtained from fetal brain tissue. Human helper (CD4⁺ ) T cells were isolated from peripheral blood mononuclear cells and activated with the superantigen staphylococcal enterotoxin E (SEE). Granzyme B was detected by enzyme linked immunosorbent assay and intracellular flow cytometry. GFAP fragmentation was monitored by western blotting. Cell death was monitored by lactic acid dehydrogenase release and terminal biotin-dUTP nick labeling (TUNEL). Astrocyte migration was monitored by scratch assay. Adult human oligodendrocytes were cultured with sublethally injured astrocytes to determine support function. Helper T cells activated with SEE expressed granzyme B but not perforin. Helper T cells released granzyme B upon contact with astrocytes and caused GFAP fragmentation in a caspase-dependent, MHCII-independent manner. Sublethally injured astrocytes were not apoptotic; however, their processes were thin and elongated, their migration was attenuated, and their ability to support oligodendrocytes was reduced in vitro. Helper T cells can release granzyme B causing sublethal injury to astrocytes, which compromises the supportive functions of astrocytes. Blocking these pathways may lead to improved resolution of neuroinflammatory lesions.

α-Synuclein and Noradrenergic Modulation of Immune Cells in Parkinson's Disease Pathogenesis

α-synuclein (α-syn) pathology and loss of noradrenergic neurons in the locus coeruleus (LC) are among the most ubiquitous features of Parkinson's disease (PD). While noradrenergic dysfunction is associated with non-motor symptoms of PD, preclinical research suggests that the loss of LC norepinephrine (NE), and subsequently its immune modulatory and neuroprotective actions, may exacerbate or even accelerate disease progression. In this review, we discuss the mechanisms by which α-syn pathology and loss of central NE may directly impact brain health by interrupting neurotrophic factor signaling, exacerbating neuroinflammation, and altering regulation of innate and adaptive immune cells.

Role of interleukin (IL)-17 and T-helper (Th)17 cells in cancer

Interleukin-17 (IL-17), a pleiotropic proinflammatory cytokine, is reported to be significantly generated by a distinct subset of CD4⁺ T-cells, upgrading cancer-elicited inflammation and preventing cancer cells from immune surveillance. T-helper (Th)17 cells produced from naive CD4⁺ T cells have recently been renowned and generally accepted, gaining eminence in cancer studies and playing the effective role in context of cancer. Th17 cells are the main source of IL-17-secreting cells, It was found that other cell types produced this cytokine as well, including Group 3 innate lymphoid cells (ILC3), δγT cells, invariant natural killer T (iNKT) cells, lymphoid-tissue inducer (LTi)-like cells and Natural killer (NK) cells. Th17-associated cytokines give impetus to tumor progression, or inducing angiogenesis and metastasis. This review demonstrates an understanding on how the pro- or antitumor function of Th17 cells and IL-17 may change cancer progression, leading to the appearance of complex and pivotal biologic activities in tumor.