scholarly journals Sympathetic influences on articular cartilage regeneration capacity and osteoarthritis manifestation

2021 ◽  
Author(s):  
◽  
Karima El Bagdadi
Keyword(s):  
Subchondral Bone ◽  
Adrenergic Receptor ◽  
Cartilage Regeneration ◽  
Cartilage Degeneration ◽  
Bone Changes ◽  
Β2 Adrenergic Receptor ◽  
Deficient Mice

The pathogenesis of osteoarthritis (OA) involves articular cartilage, synovial tissue and subchondral bone and is therefore a disease of the whole joint. OA is characterized by progressive degradation of cartilage, synovial inflammation, osteophyte formation and subchondral bone sclerosis. Cartilage-surrounding tissues are innervated by tyrosine hydroxylase (TH)-positive sympathetic nerve fibers with the most important sympathetic neurotransmitter norepinephrine (NE) detected in the synovial fluid of OA patients. Furthermore, adrenergic receptors are expressed in different knee joint tissues. Most in vitro studies indicate a potential role of the β2-adrenergic receptor, which has been not investigated during OA pathogenesis in vivo. The role of the sympathetic nervous system (SNS) in OA progression has not yet been studied. Therefore, the objective of this study was to analyze how the SNS and NE influence the MSC dependent cartilage regeneration in vitro and the OA pathogenesis and manifestation in vivo. In the first part of this study, the effect of NE on the chondrogenesis of sASC, which are known to play an important role in cartilage regeneration was analyzed in vitro. In the second part of this study, the role of the SNS was studied in vivo in mice that were sympathectomized chemically followed by surgically induced OA. The specific focus was on the β2-adrenergic receptor effects on OA pathogenesis, which were analyzed in β2-adrenergic receptor-deficient mice. The in vitro experiments have shown that NE reduced the chondrogenic potential of sASCs by decreasing the expression of type II collagen and sGAG. NE mediated these effects mainly by the α2-AR signalling. Furthermore, NE treatment led to activation of the ERK1/2 signal pathway. These findings suggested that the sympathetic neurotransmitter NE might suppress the chondrogenic capacity of MSC and their dependent cartilage regeneration and may also play a role in OA progression and manifestation. The in vivo study has shown that sympathectomy reduced synovial TH-positive nerve fibers in the synovium and the NE concentration in the spleen significantly. In WT mice, DMM leads to increased NE concentrations in the spleen compared to sham mice indicating an increased SNS activity after mechanical stress or inflammation due to DMM. Sympathectomy leads to less pronounced cartilage degeneration (OARSI score) after DMM compared to DMM in WT mice. Furthermore, the release of the type II collagen degradation fragment CTX-II was abolished in Syx DMM mice compared to WT DMM mice, suggesting that less SNS activity due to sympathectomy reduced the cartilage degeneration during OA pathogenesis. Similarly, sympathectomy decreased the synovitis score significantly after DMM compared to DMM in WT mice. Synovitis in WT mice was accompanied by increased MMP-13 expression in the synovium after DMM, compared to Syx mice. Cartilage degeneration seemed to be driven mainly by the increased synovial inflammation accompanied by an increased MMP13 expression in synoviocytes and not in chondrocytes. The pathological changes in synovium and cartilage might also be linked to each other, as indicated by the moderate correlation between the synovial inflammation (synovitis score) and cartilage degeneration (OARSI score). Subchondral bone volume as well the thickness of the subchondral bone plate (SCBP) and calcified cartilage (CC) were increased in Syx mice compared to WT after DMM. The data on DMM induction in β2-AR deficient mice revealed that the β2-AR signaling is involved in cartilage degeneration and the aggravated subchondral bone changes as these mice had less pronounced cartilage degeneration compared to WT mice. While the cartilage degeneration was similar, the subchondral bone changes were more pronounced in β2-AR deficient mice compared to the Syx mice. Overall, the SNS had differential effects in cartilage, synovium and subchondral bone. A reduced SNS activity by sympathectomy attenuated cartilage degeneration and synovitis but aggravated the OA specific subchondral bone changes. These findings provide new insights into the development of novel therapeutic strategies for OA by targeting the SNS in a tissue- specific manner.

β-blockade abolishes the augmented cardiac tPA release induced by transactivation of heterodimerised bradykinin receptor-2 and β2-adrenergic receptor in vivo

2014 ◽  
Vol 112 (11) ◽  
pp. 951-959 ◽  
Author(s):  
Morten Eriksen ◽  
Arnfinn Ilebekk ◽  
Alessandro Cataliotti ◽  
Cathrine Rein Carlson ◽  
Torstein Lyberg ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Sympathetic Nerves ◽  
Ventricular Myocardium ◽  
Left Ventricular ◽  
Left Ventricular Myocardium ◽  
Adrenergic Stimulation ◽  
Β2 Adrenergic Receptor ◽  
Β Blocker

SummaryBradykinin (BK) receptor-2 (B2R) and β2-adrenergic receptor (β2AR) have been shown to form heterodimers in vitro. However, in vivo proofs of the functional effects of B2R-β2AR heterodimerisation are missing. Both BK and adrenergic stimulation are known inducers of tPA release. Our goal was to demonstrate the existence of B2R-β2AR heterodimerisation in myocardium and to define its functional effect on cardiac release of tPA in vivo. We further investigated the effects of a non-selective β-blocker on this receptor interplay. To investigate functional effects of B2R-β2AR heterodimerisation (i. e. BK transactivation of β2AR) in vivo, we induced serial electrical stimulation of cardiac sympathetic nerves (SS) in normal pigs that underwent concomitant BK infusion. Both SS and BK alone induced increases in cardiac tPA release. Importantly, despite B2R desensitisation, simultaneous BK infusion and SS (BK+SS) was characterised by 2.3 ± 0.3-fold enhanced tPA release compared to SS alone. When β-blockade (propranolol) was introduced prior to BK+SS, tPA release was inhibited. A persistent B2R-β2AR heterodimer was confirmed in BK-stimulated and nonstimulated left ventricular myocardium by immunoprecipitation studies and under non-reducing gel conditions. All together, these results strongly suggest BK transactivation of β2AR leading to enhanced β2AR-mediated release of tPA. Importantly, non-selective β-blockade inhibits both SS-induced release of tPA and the functional effects of B2R-β2AR heterodimerisation in vivo, which may have important clinical implications.

The use of siRNA as a pharmacological tool to assess a role for the transcription factor NF-IL6 in the brain under in vitro and in vivo conditions during LPS-induced inflammatory stimulation

2017 ◽  
Vol 28 (6) ◽  
Author(s):  
Jelena Damm ◽  
Joachim Roth ◽  
Rüdiger Gerstberger ◽  
Christoph Rummel
Keyword(s):  
Transcription Factor ◽  
Brain Cells ◽  
Nuclear Factor ◽  
Si Rna ◽  
The Brain ◽  
Deficient Mice ◽  
Transcription Factor Nuclear Factor

AbstractBackground:Studies with NF-IL6-deficient mice indicate that this transcription factor plays a dual role during systemic inflammation with pro- and anti-inflammatory capacities. Here, we aimed to characterize the role of NF-IL6 specifically within the brain.Methods:In this study, we tested the capacity of short interfering (si) RNA to silence the inflammatory transcription factor nuclear factor-interleukin 6 (NF-IL6) in brain cells underResults:In cells of a mixed neuronal and glial primary culture from the ratConclusions:This approach was, thus, not suitable to characterize the role NF-IL6 in the brain

scholarly journals Interleukin 6 is essential for in vivo development of B lineage neoplasms.

1995 ◽  
Vol 182 (1) ◽  
pp. 243-248 ◽  
Author(s):  
D M Hilbert ◽  
M Kopf ◽  
B A Mock ◽  
G Köhler ◽  
S Rudikoff
Keyword(s):  
Plasma Cell ◽  
Plasma Cells ◽  
Tumor Development ◽  
Selective Pressures ◽  
B Lineage ◽  
Deficient Mice ◽  
Human B Cell

Interleukin (IL) 6 has been suggested to be the major cytokine responsible for proliferation of neoplastic plasma cells in both human myeloma and mouse plasmacytoma. Much of the evidence supporting this suggestion is derived from in vitro studies in which the survival or proliferation of some plasma cell tumors has been found to be IL-6 dependent. However, it remains unclear whether this dependency is the consequence of in vivo or in vitro selective pressures that preferentially expand IL-6-responsive tumor cells, or whether it reflects a critical in vivo role for IL-6 in plasma cell neoplasia. To address this question, we have attempted to induce plasma cell tumors in normal mice and in IL-6-deficient mice generated by introduction of a germline-encoded null mutation in the IL-6 gene. The results demonstrate that mice homozygous (+/+) or heterozygous (+/-) for the wild-type IL-6 allele yield the expected incidences of plasma cell tumors. In contrast, mice homozygous for the IL-6-null allele (-/-) are completely resistant to plasma cell tumor development. These studies define the essential role of IL-6 in the development of B lineage tumors in vivo and provide experimental support for continued efforts to modulate this cytokine in the treatment of appropriate human B cell malignancies.

scholarly journals A comprehensive protein–protein interactome for yeast PAS kinase 1 reveals direct inhibition of respiration through the phosphorylation of Cbf1

2014 ◽  
Vol 25 (14) ◽  
pp. 2199-2215 ◽  
Author(s):  
Desiree DeMille ◽  
Benjamin T. Bikman ◽  
Andrew D. Mathis ◽  
John T. Prince ◽  
Jordan T. Mackay ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Protein Modification ◽  
Molecular Mechanisms ◽  
Binding Partners ◽  
Pas Kinase ◽  
Protein Interactome ◽  
Deficient Mice

Per-Arnt-Sim (PAS) kinase is a sensory protein kinase required for glucose homeostasis in yeast, mice, and humans, yet little is known about the molecular mechanisms of its function. Using both yeast two-hybrid and copurification approaches, we identified the protein–protein interactome for yeast PAS kinase 1 (Psk1), revealing 93 novel putative protein binding partners. Several of the Psk1 binding partners expand the role of PAS kinase in glucose homeostasis, including new pathways involved in mitochondrial metabolism. In addition, the interactome suggests novel roles for PAS kinase in cell growth (gene/protein expression, replication/cell division, and protein modification and degradation), vacuole function, and stress tolerance. In vitro kinase studies using a subset of 25 of these binding partners identified Mot3, Zds1, Utr1, and Cbf1 as substrates. Further evidence is provided for the in vivo phosphorylation of Cbf1 at T211/T212 and for the subsequent inhibition of respiration. This respiratory role of PAS kinase is consistent with the reported hypermetabolism of PAS kinase–deficient mice, identifying a possible molecular mechanism and solidifying the evolutionary importance of PAS kinase in the regulation of glucose homeostasis.

scholarly journals The critical role of agrin in the hematopoietic stem cell niche

Blood ◽  
2011 ◽  
Vol 118 (10) ◽  
pp. 2733-2742 ◽  
Author(s):  
Cristina Mazzon ◽  
Achille Anselmo ◽  
Javier Cibella ◽  
Cristiana Soldani ◽  
Annarita Destro ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Critical Role ◽  
Hematopoietic Stem ◽  
Hematopoietic Stem Cell Niche ◽  
Cell Niche ◽  
Deficient Mice

Abstract Hematopoiesis is the process leading to the sustained production of blood cells by hematopoietic stem cells (HSCs). Growth, survival, and differentiation of HSCs occur in specialized microenvironments called “hematopoietic niches,” through molecular cues that are only partially understood. Here we show that agrin, a proteoglycan involved in the neuromuscular junction, is a critical niche-derived signal that controls survival and proliferation of HSCs. Agrin is expressed by multipotent nonhematopoietic mesenchymal stem cells (MSCs) and by differentiated osteoblasts lining the endosteal bone surface, whereas Lin−Sca1+c-Kit+ (LSK) cells express the α-dystroglycan receptor for agrin. In vitro, agrin-deficient MSCs were less efficient in supporting proliferation of mouse Lin−c-Kit+ cells, suggesting that agrin plays a role in the hematopoietic cell development. These results were indeed confirmed in vivo through the analysis of agrin knockout mice (Musk-L;Agrn−/−). Agrin-deficient mice displayed in vivo apoptosis of CD34+CD135− LSK cells and impaired hematopoiesis, both of which were reverted by an agrin-sufficient stroma. These data unveil a crucial role of agrin in the hematopoietic niches and in the cross-talk between stromal and hematopoietic stem cells.

scholarly journals Dependence of Mycobacterium bovis BCG on Anaerobic Nitrate Reductase for Persistence Is Tissue Specific

2002 ◽  
Vol 70 (1) ◽  
pp. 286-291 ◽  
Author(s):  
Christian Fritz ◽  
Silvia Maass ◽  
Andreas Kreft ◽  
Franz-Christoph Bange
Keyword(s):  
Nitrate Reductase ◽  
Mycobacterium Bovis ◽  
Vaccine Development ◽  
Nitrate Respiration ◽  
Apparent Paradox ◽  
Tissue Specific ◽  
Deficient Mice

ABSTRACT Mycobacterium bovis BCG, the only presently available vaccine against tuberculosis, was obtained from virulent M. bovis after serial passages in vitro. The vaccine strain retained at least some of its original virulence, as it persists in immune-competent hosts and occasionally may cause fatal disease in immune-deficient hosts. Mycobacterial persistence in vivo is thought to depend on anaerobic metabolism, an apparent paradox since all mycobacteria are obligate aerobes. Here we report that M. bovis BCG lacking anaerobic nitrate reductase (NarGHJI), an enzyme essential for nitrate respiration, failed to persist in the lungs, liver, and kidneys of immune-competent (BALB/c) mice. In immune-deficient (SCID) mice, however, bacilli caused chronic infection despite disruption of narG, even if growth of the mutant was severely impaired in lungs, liver, and kidneys. Persistence and growth of BCG in the spleens of either mouse strain appeared largely unaffected by lack of anaerobic nitrate reductase, indicating that the role of the enzyme in pathogenesis is tissue specific. These data suggest first that anaerobic nitrate reduction is essential for metabolism of M. bovis BCG in immune-competent but not immune-deficient mice and second that its role in mycobacterial disease is tissue specific, both of which are observations with important implications for pathogenesis of mycobacteria and vaccine development.

Dendritic cell-derived IL-2 production is regulated by IL-15 in humans and in mice

Blood ◽  
2005 ◽  
Vol 105 (2) ◽  
pp. 697-702 ◽  
Author(s):  
Sonia Feau ◽  
Valeria Facchinetti ◽  
Francesca Granucci ◽  
Stefania Citterio ◽  
David Jarrossay ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
T Cell ◽  
Molecular Mechanisms ◽  
Interleukin 2 ◽  
Adaptive Immune ◽  
Deficient Mice ◽  
Mouse System

Abstract Dendritic cells (DCs) are involved in the initiation and regulation of innate and adaptive immune responses. Several molecular mechanisms regulate these diverse DC functions, and we have previously reported that mouse dendritic cells (mDCs) can produce interleukin-2 (IL-2) in vitro and in vivo, in response to microbial activation and T-cell-mediated stimuli. This property is shared by different DC subtypes, including Langerhans cells. Here we show that, on appropriate stimulation, human DCs, both plasmacytoid and myeloid subtypes, also express IL-2. Interestingly, the production of IL-2 by myeloid DCs is induced by T-cell-mediated stimuli and depends on the presence of IL-15. The key role of this cytokine in regulating IL-2 production was also confirmed in the mouse system. In particular, we could show that DCs from IL-15-deficient mice were strongly impaired in the ability to produce IL-2 after interactions with different microbial stimuli. Our results indicate that DC-produced IL-2 is tightly coregulated with the expression of IL-15.

scholarly journals Basal Polarity Complex Scribble Is Required for Leukemic Initiation and Propagation through Negative Regulation of Apical Polarity Complex Activator Cdc42 and Hypoxia Inducing Factor-1α

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 551-551
Author(s):  
Shailaja N Hegde ◽  
Mark J Althoff ◽  
Ramesh C. Nayak ◽  
Ashley M Wellendorf ◽  
Fatima Mohmoud ◽  
...  
Keyword(s):  
Median Survival ◽  
Leukemic Cells ◽  
Mtorc1 Signaling ◽  
Apical Polarity ◽  
B Lymphoid ◽  
Deficient Mice ◽  
Expression And Activity

Abstract Despite the introduction of tyrosine kinase inhibitor and CAR-T cell therapies, the prognosis for Ph+ and Ph-like acute lymphoblastic leukemia remains poor. In the present study, we show the role of the Scribble protein in both lymphoid and myeloid leukemogenesis. The polarity protein Scribble is a member of the basal polarity complex, which is down-regulated in many cancers, suggesting a possible tumor suppressor role, especially in so-called cancer initiating cells. Its effect and mechanisms of activity in leukemic cell fate along with its potential activity on leukemic initiating cells have only been recently started to elucidated. Using interferon-responsive inducible (Mx1-Cre) Scribble-deficient mice, we have characterized the role of Scribble in both retroviral transduction, transplantation animal models and binary, inducible stem cell initiated (Scl-tTA/TRE-BCR-ABL) serial propagation models of BCR-ABL induced leukemia. We found that Scribble expression is upregulated at both transcriptional and translational levels in p210- or p190-BCR-ABL induced leukemic progenitors. In vitro, leukemic colony formation was impaired in Scribble deficient leukemic progenitors (~48% reduction; p≤ 0.05, compared to Wt leukemic progenitors) demonstrating that Scribble is important for leukemogenesis. In vivo, the deletion of Scribble abrogates the development of myeloproliferative disease induced by p210-BCR-ABL (median survival: 70 vs 47 days in Scribble deficient and Wt chimeric mice, respectively; p≤0.05); and significantly impairs B-cell lymphoid leukemogenesis induced by p190-BCR-ABL (median survival: 80 vs 60 days for Scribble deficient and Wt chimeric animals, respectively). Mechanistically, BCR-ABL activates the apical polarity regulator Cdc42 in leukemic progenitors and this activation is inhibited by the deficiency of Scribble. The deficiency of Cdc42 does not impair leukemogenesis but the combined deficiency of Cdc42 and Scribble restores the in vivo survival (median survival: 47 days, p≤0.01 compared to Scribble deficient mice) in chimeric p190-BCR-ABL+ leukemic mice to levels similar to wild-type leukemic cells. These data indicate that Scribble-deficient leukemogenesis is dependent on oncogene induced Cdc42 activity in lymphoid progenitors. Furthermore, Scribble deficiency in leukemic progenitors increases the activation of the AMPK/mTORC1 signaling pathway and the protein expression and transcriptional activity of its downstream effector hypoxia-inducing factor-1α (HIF-1α). HIF-1α silencing by constitutive shRNA expression or inducible deletion in Scribble deleted B-lymphoid leukemic cells restored leukemic progenitor clonogenic efficiency (CFU average: 52 vs 110 per 1,000 B220+/EGFP+ BM cells, in Scribble and double Scribble/HIF-1α deficient, respectively; p≤0.01) and B-lymphoid leukemogenesis in vivo (median survival of 62 days; p≤0.05 compared with Scribble deficient chimeric animals). In addition, double deficiency of Scribble and HIF-1α restored AMPK/mTORC1 signaling to Wt leukemic levels. This data indicates that Scribble is a negative regulator of HIF-1α expression and activity, and the restoration of HIF-1α expression and activity to normal leukemic levels is necessary to restore leukemogenesis. Altogether, our data indicates that Scribble is a positive regulator of oncogenesis in leukemic progenitors, in vitro and in vivo, through Cdc42 and HIF-1α activities. Disclosures No relevant conflicts of interest to declare.

scholarly journals ASXL2 Is Recurrently Mutated in t(8;21) AML and Regulates Hematopoietic Development

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1051-1051
Author(s):  
Vikas Madan ◽  
Lin Han ◽  
Norimichi Hattori ◽  
Anand Mayakonda ◽  
Qiao-Yang Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Research Funding ◽  
Hematopoietic Differentiation ◽  
Wild Type ◽  
Flow Cytometric ◽  
Deficient Mice

Abstract Chromosomal translocation t(8;21) (q22;q22) leading to generation of oncogenic RUNX1-RUNX1T1 fusion is a cytogenetic abnormality observed in about 10% of acute myelogenous leukemia (AML). Studies in animal models and recent next generation sequencing approaches have suggested cooperativity of secondary genetic lesions with t(8;21) in inducing leukemogenesis. In this study, we used targeted and whole exome sequencing of 93 cases (including 30 with matched relapse samples) to profile the mutational landscape of t(8;21) AML at initial diagnosis and post-therapy relapse. We identified recurrent mutations of KIT, TET2, MGA, FLT3, NRAS, DHX15, ASXL1 and KMT2Dgenes in this subtype of AML. In addition, high frequency of truncating alterations in ASXL2 gene (19%) also occurred in our cohort. ASXL2 is a member of mammalian ASXL family involved in epigenetic regulation through recruitment of polycomb or trithorax complexes. Unlike its closely related homolog ASXL1, which is mutated in several hematological malignancies including AML, MDS, MPN and others; mutations of ASXL2 occur specifically in t(8;21) AML. We observed that lentiviral shRNA-mediated silencing of ASXL2 impaired in vitro differentiation of t(8;21) AML cell line, Kasumi-1, and enhanced its colony forming ability. Gene expression analysis uncovered dysregulated expression of several key hematopoiesis genes such as IKZF2, JAG1, TAL1 and ARID5B in ASXL2 knockdown Kasumi-1 cells. Further, to investigate implications of loss of ASXL2 in vivo, we examined hematopoiesis in Asxl2 deficient mice. We observed an age-dependent increase in white blood cell count in the peripheral blood of Asxl2 KO mice. Myeloid progenitors from Asxl2 deficient mice possessed higher re-plating ability and displayed altered differentiation potential in vitro. Flow cytometric analysis of >1 year old mice revealed increased proportion of Lin-Sca1+Kit+ (LSK) cells in the bone marrow of Asxl2 deficient mice, while the overall bone marrow cellularity was significantly reduced. In vivo 5-bromo-2'-deoxyuridine incorporation assay showed increased cycling of LSK cells in mice lacking Asxl2. Asxl2 deficiency also led to perturbed maturation of myeloid and erythroid precursors in the bone marrow, which resulted in altered proportions of mature myeloid populations in spleen and peripheral blood. Further, splenomegaly was observed in old ASXL2 KO mice and histological and flow cytometric examination of ASXL2 deficient spleens demonstrated increased extramedullary hematopoiesis and myeloproliferation compared with the wild-type controls. Surprisingly, loss of ASXL2 also led to impaired T cell development as indicated by severe block in maturation of CD4-CD8- double negative (DN) population in mice >1 year old. These findings established a critical role of Asxl2 in maintaining steady state hematopoiesis. To gain mechanistic insights into its role during hematopoietic differentiation, we investigated changes in histone marks and gene expression affected by loss of Asxl2. Whole transcriptome sequencing of LSK population revealed dysregulated expression of key myeloid-specific genes including Mpo, Ltf, Ngp Ctsg, Camp and Csf1rin cells lacking Asxl2 compared to wild-type control. Asxl2 deficiency also caused changes in histone modifications, specifically H3K27 trimethylation levels were decreased and H2AK119 ubiquitination levels were increased in Asxl2 KO bone marrow cells. Global changes in histone marks in control and Asxl2 deficient mice are being investigated using ChIP-Sequencing. Finally, to examine cooperativity between the loss of Asxl2 and RUNX1-RUNX1T1 in leukemogenesis, KO and wild-type fetal liver cells were transduced with retrovirus expressing AML1-ETO 9a oncogene and transplanted into irradiated recipient mice, the results of this ongoing study will be discussed. Overall, our sequencing studies have identified ASXL2 as a gene frequently altered in t(8;21) AML. Functional studies in mouse model reveal that loss of ASXL2 causes defects in hematopoietic differentiation and leads to myeloproliferation, suggesting an essential role of ASXL2 in normal and malignant hematopoiesis. *LH and NH contributed equally Disclosures Ogawa: Takeda Pharmaceuticals: Consultancy, Research Funding; Sumitomo Dainippon Pharma: Research Funding; Kan research institute: Consultancy, Research Funding.

scholarly journals MO330ACTIVATION OF Β2 ADRENERGIC RECEPTOR SIGNALING IN MACROPHAGES BLOCKS SYSTEMIC INFLAMMATION AND PROTECTS AGAINST RENAL ISCHEMIA/REPERFUSION INJURY

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Sho Hasegawa ◽  
Tsuyoshi Inoue ◽  
Masaomi Nangaku ◽  
Reiko Inagi
Keyword(s):  
Rna Sequencing ◽  
Systemic Inflammation ◽  
Adrenergic Receptor ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Renal Tissue ◽  
Β2 Adrenergic Receptor ◽  
Anti Inflammatory

Abstract Background and Aims The sympathetic nervous system regulates immune cell dynamics. However, the detailed role of sympathetic signaling in inflammatory diseases is still unclear because it varies according to the disease situation and responsible cell types. Here, we focused on sympathetic signaling in macrophages and sought to determine its detailed roles in lipopolysaccharide (LPS)-induced systemic inflammation and renal ischemia/reperfusion injury (IRI). Method In vitro, RAW 264.7 cells and murine peritoneal macrophages were used to determine the effects of β2 adrenergic receptor (Adrb2) signaling on LPS-induced proinflammatory cytokine (tumor necrosis factor-α; TNF-α) production. We also identified the critical gene that mediates the anti-inflammatory effect of Adrb2 signaling by RNA-sequencing. In vivo, we examined the effects of salbutamol (a selective Adrb2 agonist) in LPS-induced systemic inflammation and renal IRI. The involvement of macrophage Adrb2 signaling was confirmed by macrophage-specific Adrb2 conditional knockout (cKO) mice and adoptive transfer of salbutamol-treated macrophages. We also performed single-cell RNA sequencing of renal tissue to analyze the renoprotective role of salbutamol-treated macrophages in detail. Results In vitro, norepinephrine, a sympathetic neurotransmitter, suppressed LPS-induced TNF-α production in macrophages. This anti-inflammatory effect was also induced by salbutamol and reversed by butoxamine (a selective Adrb2 antagonist) in a dose-dependent manner, indicating the importance of Adrb2 in this process. RNA sequencing of these macrophages revealed that T-cell immunoglobulin and mucin-3 (Tim3) expressions were upregulated by the activation of Adrb2 signaling, which partially mediated the anti-inflammatory phenotypic alteration in macrophages. In vivo, salbutamol administration mitigated LPS-induced systemic inflammation and protected against renal IRI; this protection was mitigated in macrophage-specific Adrb2 cKO mice. Adoptive transfer of salbutamol-treated macrophages also protected against renal IRI (Figure 1). Single-cell RNA sequencing revealed that this protection was associated with the accumulation of Tim3-expressing macrophages in the renal tissue. Conclusion The activation of β2 adrenergic receptor signaling in macrophages induces anti-inflammatory phenotypic alterations partially via the induction of Tim3 expressions, which blocks LPS-induced systemic inflammation and protects against renal IRI.

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