Publications by authors named "Hal M Hoffman"

124 Publications

NOD-like receptor protein 3 activation causes spontaneous inflammation and fibrosis that mimics human NASH.

Hepatology 2022 Jan 8. Epub 2022 Jan 8.

Department of Bioengineering, University of California San Diego, San Diego, California, USA.

Background And Aims: The NOD-like receptor protein 3 (NLRP3) inflammasome is a central contributor to human acute and chronic liver disease, yet the molecular and cellular mechanisms by which its activation precipitates injury remain incompletely understood. Here, we present single cell transcriptomic profiling of livers from a global transgenic tamoxifen-inducible constitutively activated Nlrp3 mutant mouse, and we investigate the changes in parenchymal and nonparenchymal liver cell gene expression that accompany inflammation and fibrosis.

Approach And Results: Our results demonstrate that NLRP3 activation causes chronic extramedullary myelopoiesis marked by myeloid progenitors that differentiate into proinflammatory neutrophils, monocytes, and monocyte-derived macrophages. We observed prominent neutrophil infiltrates with increased Ly6g and Ly6g cells exhibiting transcriptomic signatures of granulopoiesis typically found in the bone marrow. This was accompanied by a marked increase in Ly6c monocytes differentiating into monocyte-derived macrophages that express transcriptional programs similar to macrophages of NASH models. NLRP3 activation also down-regulated metabolic pathways in hepatocytes and shifted hepatic stellate cells toward an activated profibrotic state based on expression of collagen and extracellular matrix regulatory genes.

Conclusions: These results define the single cell transcriptomes underlying hepatic inflammation and fibrosis precipitated by NLRP3 activation. Clinically, our data support the notion that NLRP3-induced mechanisms should be explored as therapeutic target in NASH-like inflammation.
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http://dx.doi.org/10.1002/hep.32320DOI Listing
January 2022

Activin A Signaling Provides an Interorgan Link Between Kidney and Muscle in CKD-Associated Muscle Wasting.

Am J Kidney Dis 2022 02 12;79(2):302-304. Epub 2021 Oct 12.

Department of Pediatrics, Rady Children's Hospital, University of California-San Diego, San Diego, California. Electronic address:

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http://dx.doi.org/10.1053/j.ajkd.2021.09.007DOI Listing
February 2022

Neutrophil-specific gain-of-function mutations in Nlrp3 promote development of cryopyrin-associated periodic syndrome.

J Exp Med 2021 10 3;218(10). Epub 2021 Sep 3.

Unit of Antibodies in Therapy and Pathology, Institut Pasteur, UMR 1222, Institut national de la santé et de la recherche médicale, Paris, France.

Gain-of-function mutations in NLRP3 are responsible for a spectrum of autoinflammatory diseases collectively referred to as "cryopyrin-associated periodic syndromes" (CAPS). Treatment of CAPS patients with IL-1-targeted therapies is effective, confirming a central pathogenic role for IL-1β. However, the specific myeloid cell population(s) exhibiting inflammasome activity and sustained IL-1β production in CAPS remains elusive. Previous reports suggested an important role for mast cells (MCs) in this process. Here, we report that, in mice, gain-of-function mutations in Nlrp3 restricted to neutrophils, and to a lesser extent macrophages/dendritic cells, but not MCs, are sufficient to trigger severe CAPS. Furthermore, in patients with clinically established CAPS, we show that skin-infiltrating neutrophils represent a substantial biological source of IL-1β. Together, our data indicate that neutrophils, rather than MCs, can represent the main cellular drivers of CAPS pathology.
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http://dx.doi.org/10.1084/jem.20201466DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8421266PMC
October 2021

Immune response to intravenous immunoglobulin in patients with Kawasaki disease and MIS-C.

J Clin Invest 2021 10;131(20)

Department of Pediatrics and.

BACKGROUNDMultisystem inflammatory syndrome in children (MIS-C) is a rare but potentially severe illness that follows exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Kawasaki disease (KD) shares several clinical features with MIS-C, which prompted the use of intravenous immunoglobulin (IVIG), a mainstay therapy for KD. Both diseases share a robust activation of the innate immune system, including the IL-1 signaling pathway, and IL-1 blockade has been used for the treatment of both MIS-C and KD. The mechanism of action of IVIG in these 2 diseases and the cellular source of IL-1β have not been defined.METHODSThe effects of IVIG on peripheral blood leukocyte populations from patients with MIS-C and KD were examined using flow cytometry and mass cytometry (CyTOF) and live-cell imaging.RESULTSCirculating neutrophils were highly activated in patients with KD and MIS-C and were a major source of IL-1β. Following IVIG treatment, activated IL-1β+ neutrophils were reduced in the circulation. In vitro, IVIG was a potent activator of neutrophil cell death via PI3K and NADPH oxidase, but independently of caspase activation.CONCLUSIONSActivated neutrophils expressing IL-1β can be targeted by IVIG, supporting its use in both KD and MIS-C to ameliorate inflammation.FUNDINGPatient Centered Outcomes Research Institute; NIH; American Asthma Foundation; American Heart Association; Novo Nordisk Foundation; NIGMS; American Academy of Allergy, Asthma and Immunology Foundation.
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http://dx.doi.org/10.1172/JCI147076DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8516453PMC
October 2021

The role of IL-1 in adipose browning and muscle wasting in CKD-associated cachexia.

Sci Rep 2021 07 23;11(1):15141. Epub 2021 Jul 23.

Division of Pediatric Nephrology, Rady Children's Hospital, University of California, San Diego, 9500 Gilman Drive, MC 0831, La Jolla, CA, 92093-0831, USA.

Cytokines such as IL-6, TNF-α and IL-1β trigger inflammatory cascades which may play a role in the pathogenesis of chronic kidney disease (CKD)-associated cachexia. CKD was induced by 5/6 nephrectomy in mice. We studied energy homeostasis in Il1β/CKD, Il6/CKD and Tnfα/CKD mice and compared with wild type (WT)/CKD controls. Parameters of cachexia phenotype were completely normalized in Il1β/CKD mice but were only partially rescued in Il6/CKD and Tnfα/CKD mice. We tested the effects of anakinra, an IL-1 receptor antagonist, on CKD-associated cachexia. WT/CKD mice were treated with anakinra (2.5 mg/kg/day, IP) or saline for 6 weeks and compared with WT/Sham controls. Anakinra normalized food intake and weight gain, fat and lean mass content, metabolic rate and muscle function, and also attenuated molecular perturbations of energy homeostasis in adipose tissue and muscle in WT/CKD mice. Anakinra decreased serum and muscle expression of IL-6, TNF-α and IL-1β in WT/CKD mice. Anakinra attenuated browning of white adipose tissue in WT/CKD mice. Moreover, anakinra normalized gastrocnemius weight and fiber size as well as attenuated muscle fat infiltration in WT/CKD mice. This was accompanied by correcting the increased muscle wasting signaling pathways while promoting the decreased myogenesis process in gastrocnemius of WT/CKD mice. We performed qPCR analysis for the top 20 differentially expressed muscle genes previously identified via RNAseq analysis in WT/CKD mice versus controls. Importantly, 17 differentially expressed muscle genes were attenuated in anakinra treated WT/CKD mice. In conclusion, IL-1 receptor antagonism may represent a novel targeted treatment for adipose tissue browning and muscle wasting in CKD.
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http://dx.doi.org/10.1038/s41598-021-94565-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8302616PMC
July 2021

Inflammasome Activation in Children With Kawasaki Disease and Multisystem Inflammatory Syndrome.

Arterioscler Thromb Vasc Biol 2021 09 15;41(9):2509-2511. Epub 2021 Jul 15.

Division of Cardiology, Department of Medicine (W.-T.W., M.H., J.Y.-J.S.), University of California, San Diego, La Jolla.

[Figure: see text].
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http://dx.doi.org/10.1161/ATVBAHA.121.316210DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8387357PMC
September 2021

Targeting interleukin-1 for reversing fat browning and muscle wasting in infantile nephropathic cystinosis.

J Cachexia Sarcopenia Muscle 2021 10 30;12(5):1296-1311. Epub 2021 Jun 30.

Division of Pediatric Nephrology, Department of Pediatrics, Rady Children's Hospital San Diego, University of California, San Diego, La Jolla, CA, USA.

Background: Ctns mice, a mouse model of infantile nephropathic cystinosis, exhibit hypermetabolism with adipose tissue browning and profound muscle wasting. Inflammatory cytokines such as interleukin (IL)-1 trigger inflammatory cascades and may be an important cause for cachexia. We employed genetic and pharmacological approaches to investigate the effects of IL-1 blockade in Ctns mice.

Methods: We generated Ctns Il1β mice, and we treated Ctns and wild-type control mice with IL-1 receptor antagonist, anakinra (2.5 mg/kg/day, IP) or saline as vehicle for 6 weeks. In each of these mouse lines, we characterized the cachexia phenotype consisting of anorexia, loss of weight, fat mass and lean mass, elevation of metabolic rate, and reduced in vivo muscle function (rotarod activity and grip strength). We quantitated energy homeostasis by measuring the protein content of uncoupling proteins (UCPs) and adenosine triphosphate in adipose tissue and skeletal muscle. We measured skeletal muscle fiber area and intramuscular fatty infiltration. We also studied expression of molecules regulating adipose tissue browning and muscle mass metabolism. Finally, we evaluated the impact of anakinra on the muscle transcriptome in Ctns mice.

Results: Skeletal muscle expression of IL-1β was significantly elevated in Ctns mice relative to wild-type control mice. Cachexia was completely normalized in Ctns Il1β mice relative to Ctns mice. We showed that anakinra attenuated the cachexia phenotype in Ctns mice. Anakinra normalized UCPs and adenosine triphosphate content of adipose tissue and muscle in Ctns mice. Anakinra attenuated aberrant expression of beige adipose cell biomarkers (UCP-1, CD137, Tmem26, and Tbx1) and molecules implicated in adipocyte tissue browning (Cox2/Pgf2α, Tlr2, Myd88, and Traf6) in inguinal white adipose tissue in Ctns mice. Moreover, anakinra normalized gastrocnemius weight and fiber size and attenuated muscle fat infiltration in Ctns mice. This was accompanied by correction of the increased muscle wasting signalling pathways (increased protein content of ERK1/2, JNK, p38 MAPK, and nuclear factor-κB p65 and mRNA expression of Atrogin-1 and Myostatin) and the decreased myogenesis process (decreased mRNA expression of MyoD and Myogenin) in the gastrocnemius muscle of Ctns mice. Previously, we identified the top 20 differentially expressed skeletal muscle genes in Ctns mice by RNAseq. Aberrant expression of these 20 genes have been implicated in muscle wasting, increased energy expenditure, and lipolysis. We showed that anakinra attenuated 12 of those top 20 differentially expressed muscle genes in Ctns mice.

Conclusions: Anakinra may provide a targeted novel therapy for patients with infantile nephropathic cystinosis.
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http://dx.doi.org/10.1002/jcsm.12744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8517356PMC
October 2021

Long-term safety and effectiveness of canakinumab therapy in patients with cryopyrin-associated periodic syndrome: results from the β-Confident Registry.

RMD Open 2021 05;7(2)

Division of Pediatric Rheumatology, Department of Paediatrics and Autoinflammation Reference Center Tuebingen, University Hospital Tuebingen, Tübingen, Germany.

Objective: To report the long-term safety and effectiveness of canakinumab, a fully human anti-interleukin 1β monoclonal antibody, in patients with cryopyrin-associated periodic syndromes (CAPS), including familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and neonatal-onset multisystem inflammatory disease (NOMID), in a real-world setting.

Methods: From December 2009 to December 2015, the β-Confident Registry prospectively enrolled patients with CAPS and non-CAPS conditions who received canakinumab per routine care and were prospectively followed for up to 6 years. The registry protocol did not mandate specific visits or procedures; however, all observed adverse events (AEs) and serious adverse events (SAEs) had to be recorded. Canakinumab effectiveness was evaluated by Physician's Global Assessment (PGA).

Results: Of 288 patients enrolled, 3 were excluded due to missing informed consent. Among the remaining 285 patients, 243 (85.3%) were patients with CAPS and 42 (14.7%) had atypical CAPS (6.3%) or other conditions (8.4%). The median age was 26.6 years. Based on PGA, 58 of 123 (47.2%) patients with CAPS had no disease activity at 48 months, and 65 of 123 (52.8%) experienced mild/moderate disease activity at 48 months. Among CAPS phenotypes, AE incidence rates per 100 patient-years were lowest for FCAS (73.1; 95% CI 60.3 to 87.8) compared with those with MWS (105.0; 95% CI 97.2 to 113.2) or NOMID (104.6; 95% CI 86.6 to 125.2). One hundred twenty-eight SAEs were reported in 68 patients with CAPS (incidence rate/100 patient-years, 14.0; 95% CI 11.6 to 16.6). One death (metastatic rectal adenocarcinoma in a patient with MWS) was reported.

Conclusions: The response to canakinumab was sustained for up to 6 years. Canakinumab demonstrated a favourable safety profile over long-term treatment in patients with CAPS.

Trial Registration Number: NCT01213641.
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http://dx.doi.org/10.1136/rmdopen-2021-001663DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8130749PMC
May 2021

Inhibition of the NLRP3 inflammasome prevents ovarian aging.

Sci Adv 2021 01 1;7(1). Epub 2021 Jan 1.

Cátedra de Reproducción y Genética Humana del Instituto para el Estudio de la Biología de la Reproducción Humana (INEBIR)-Universidad Europea del Atlántico (UNEATLANTICO)-Fundación Universitaria Iberoamericana (FUNIBER), Seville, Spain.

Inflammation is a hallmark of aging and is negatively affecting female fertility. In this study, we evaluate the role of the NLRP3 inflammasome in ovarian aging and female fertility. Age-dependent increased expression of NLRP3 in the ovary was observed in WT mice during reproductive aging. High expression of NLRP3, caspase-1, and IL-1β was also observed in granulosa cells from patients with ovarian insufficiency. Ablation of NLRP3 improved the survival and pregnancy rates and increased anti-Müllerian hormone levels and autophagy rates in ovaries. Deficiency of NLRP3 also reduced serum FSH and estradiol levels. Consistent with these results, pharmacological inhibition of NLRP3 using a direct NLRP3 inhibitor, MCC950, improved fertility in female mice to levels comparable to those of mice. These results suggest that the NLRP3 inflammasome is implicated in the age-dependent loss of female fertility and position this inflammasome as a potential new therapeutic target for the treatment of infertility.
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http://dx.doi.org/10.1126/sciadv.abc7409DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7775749PMC
January 2021

Monogenic autoinflammatory disorders: Conceptual overview, phenotype, and clinical approach.

J Allergy Clin Immunol 2020 11;146(5):925-937

Division of Pediatric Allergy, Immunology, and Rheumatology, Rady Children's Hospital and University of California at San Diego, San Diego, Calif.

Autoinflammatory diseases are conditions in which pathogenic inflammation arises primarily through antigen-independent hyperactivation of immune pathways. First recognized just over 2 decades ago, the autoinflammatory disease spectrum has expanded rapidly to include more than 40 distinct monogenic conditions. Related mechanisms contribute to common conditions such as gout and cardiovascular disease. Here, we review the basic concepts underlying the "autoinflammatory revolution" in the understanding of immune-mediated disease and introduce major categories of monogenic autoinflammatory disorders recognized to date, including inflammasomopathies and other IL-1-related conditions, interferonopathies, and disorders of nuclear factor kappa B and/or aberrant TNF activity. We highlight phenotypic presentation as a reflection of pathogenesis and outline a practical approach to the evaluation of patients with suspected autoinflammation.
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http://dx.doi.org/10.1016/j.jaci.2020.08.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7727443PMC
November 2020

Pediatric recurrent fever and autoinflammation from the perspective of an allergist/immunologist.

J Allergy Clin Immunol 2020 11 28;146(5):960-966.e2. Epub 2020 Sep 28.

Division of Allergy, Immunology & Rheumatology, Department of Pediatrics, University of California, San Diego, Rady Children's Hospital, San Diego, Calif.

Autoinflammatory diseases are monogenic and polygenic disorders due to dysregulation of the innate immune system. The inherited conditions have been clustered with primary immunodeficiencies in the latest practice parameters; however, these diseases have unique clinical presentations, genetics, and available therapies. Given the presentation of fevers, rashes, and mucosal symptoms observed in many of these syndromes, patients are likely to present to an allergist/immunologist. Although there has been attention in the literature to diagnosis and treatment of rare, genetically defined autoinflammatory disorders, physicians are challenged by increasing numbers of patients with intermittent or periodic fevers who face unnecessary morbidities due to a lack of a diagnosis. The broad differential of diseases presenting with fever includes autoinflammatory syndromes, infections associated with immunodeficiency and/or allergies complicated by infection, and less commonly, autoimmune disorders or malignancy. To address this challenge, we review the history of the medical approach to fever, current diagnostic paradigms, and controversies in management. We describe the spectrum of disorders referred to a recurrent fever disorders clinic established in an Allergy/Immunology division at a tertiary pediatric care center. Finally, we provide practical recommendations including historical features and initial laboratory investigations that can help clinicians appropriately manage these patients.
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http://dx.doi.org/10.1016/j.jaci.2020.09.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8559310PMC
November 2020

Vitamin D ameliorates adipose browning in chronic kidney disease cachexia.

Sci Rep 2020 08 25;10(1):14175. Epub 2020 Aug 25.

Pediatric Nephrology, Rady Children's Hospital San Diego, University of California, San Diego, USA.

Patients with chronic kidney disease (CKD) are often 25(OH)D and 1,25(OH)D insufficient. We studied whether vitamin D repletion could correct aberrant adipose tissue and muscle metabolism in a mouse model of CKD-associated cachexia. Intraperitoneal administration of 25(OH)D and 1,25(OH)D (75 μg/kg/day and 60 ng/kg/day respectively for 6 weeks) normalized serum concentrations of 25(OH)D and 1,25(OH)D in CKD mice. Vitamin D repletion stimulated appetite, normalized weight gain, and improved fat and lean mass content in CKD mice. Vitamin D supplementation attenuated expression of key molecules involved in adipose tissue browning and ameliorated expression of thermogenic genes in adipose tissue and skeletal muscle in CKD mice. Furthermore, repletion of vitamin D improved skeletal muscle fiber size and in vivo muscle function, normalized muscle collagen content and attenuated muscle fat infiltration as well as pathogenetic molecular pathways related to muscle mass regulation in CKD mice. RNAseq analysis was performed on the gastrocnemius muscle. Ingenuity Pathway Analysis revealed that the top 12 differentially expressed genes in CKD were correlated with impaired muscle and neuron regeneration, enhanced muscle thermogenesis and fibrosis. Importantly, vitamin D repletion normalized the expression of those 12 genes in CKD mice. Vitamin D repletion may be an effective therapeutic strategy for adipose tissue browning and muscle wasting in CKD patients.
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http://dx.doi.org/10.1038/s41598-020-70190-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7447759PMC
August 2020

Opportunistic Invasive Infection by Group A Streptococcus During Anti-Interleukin-6 Immunotherapy.

J Infect Dis 2021 04;223(7):1260-1264

Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA.

Invasive group A Streptococcus (GAS) in immunocompetent individuals is largely linked to hypervirulent strains. Congenital immunodeficiencies and those acquired from chronic disease or immunosuppressant drugs also increase risk of severe illness. We recovered GAS from the blood of a patient receiving a biologic inhibitor of interleukin 6 (IL-6). Growth of this serotype M4 isolate in human blood or a murine bacteremia model was promoted by interleukin 1 or IL-6 inhibition. Hyperinvasive M1T1 GAS was unaffected by IL-6 in both models. These findings based on a natural experiment introduce IL-6 signaling deficiencies as a risk factor for invasive GAS.
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http://dx.doi.org/10.1093/infdis/jiaa511DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8030709PMC
April 2021

Hepatocyte pyroptosis and release of inflammasome particles induce stellate cell activation and liver fibrosis.

J Hepatol 2021 01 4;74(1):156-167. Epub 2020 Aug 4.

Department of Pediatrics, University of California San Diego, La Jolla, CA, USA. Electronic address:

Background & Aims: Increased hepatocyte death contributes to the pathology of acute and chronic liver diseases. However, the role of hepatocyte pyroptosis and extracellular inflammasome release in liver disease is unknown.

Methods: We used primary mouse and human hepatocytes, hepatocyte-specific leucine 351 to proline Nlrp3CreA mice, and Gsdmd mice to investigate pyroptotic cell death in hepatocytes and its impact on liver inflammation and damage. Extracellular NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasomes were isolated from mutant NLRP3-YFP HEK cells and internalisation was studied in LX2 and primary human hepatic stellate cells. We also examined a cohort of 154 adult patients with biopsy-proven non-alcoholic fatty liver disease (Sir Charles Gairdner Hospital, Nedlands, Western Australia).

Results: We demonstrated that primary mouse and human hepatocytes can undergo pyroptosis upon NLRP3 inflammasome activation with subsequent release of NLRP3 inflammasome proteins that amplify and perpetuate inflammasome-driven fibrogenesis. Pyroptosis was inhibited by blocking caspase-1 and gasdermin D activation. The activated form of caspase-1 was detected in the livers and in serum from patients with non-alcoholic steatohepatitis and correlated with disease severity. Nlrp3CreA mice showed spontaneous liver fibrosis under normal chow diet, and increased sensitivity to liver damage and inflammation after treatment with low dose lipopolysaccharide. Mechanistically, hepatic stellate cells engulfed extracellular NLRP3 inflammasome particles leading to increased IL-1β secretion and α-smooth muscle actin expression. This effect was abrogated when cells were pre-treated with the endocytosis inhibitor cytochalasin B.

Conclusions: These results identify hepatocyte pyroptosis and release of inflammasome components as a novel mechanism to propagate liver injury and liver fibrosis development.

Lay Summary: Our findings identify a novel mechanism of inflammation in the liver. Experiments in cell cultures, mice, and human samples show that a specific form of cell death, called pyroptosis, leads to the release of complex inflammatory particles, the NLRP3 inflammasome, from inside hepatocytes into the extracellular space. From there they are taken up by other cells and thereby mediate inflammatory and pro-fibrogenic stress signals. The discovery of this mechanism may lead to novel treatments for chronic liver diseases in the future.
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http://dx.doi.org/10.1016/j.jhep.2020.07.041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7749849PMC
January 2021

ASK1 inhibition reduces cell death and hepatic fibrosis in an Nlrp3 mutant liver injury model.

JCI Insight 2020 01 30;5(2). Epub 2020 Jan 30.

Department of Pediatrics, School of Medicine, UCSD, La Jolla, California, USA.

Hepatic inflammasome activation is considered a major contributor to liver fibrosis in NASH. Apoptosis signal-regulating kinase 1 (ASK1) is an apical mitogen-activated protein kinase that activates hepatic JNK and p38 to promote apoptosis, inflammation, and fibrosis. The aim of the current study was to investigate whether pharmacologic inhibition of ASK1 could attenuate hepatic fibrosis driven by inflammasome activation using gain-of-function NOD-like receptor protein 3 (Nlrp3) mutant mice. Tamoxifen-inducible Nlrp3 knock-in (Nlrp3A350V/+CreT-KI) mice and WT mice were administered either control chow diet or diet containing the selective ASK1 inhibitor GS-444217 for 6 weeks. Livers of Nlrp3-KI mice had increased inflammation, cell death, and fibrosis and increased phosphorylation of ASK1, p38, and c-Jun. GS-444217 reduced ASK1 pathway activation, liver cell death, and liver fibrosis. ASK1 inhibition resulted in a significant downregulation of genes involved in collagen production and extracellular matrix deposition, as well as in a reduced hepatic TNF-α expression. ASK1 inhibition also directly reduced LPS-induced gene expression of Collagen 1A1 (Col1a1) in hepatic stellate cells isolated from Nlrp3-KI mice. In conclusion, ASK1 inhibition reduced liver cell death and fibrosis downstream of inflammatory signaling induced by NLRP3. These data provide mechanistic insight into the antifibrotic mechanisms of ASK1 inhibition.
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http://dx.doi.org/10.1172/jci.insight.123294DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098717PMC
January 2020

Vitamin D repletion ameliorates adipose tissue browning and muscle wasting in infantile nephropathic cystinosis-associated cachexia.

J Cachexia Sarcopenia Muscle 2020 02 13;11(1):120-134. Epub 2019 Nov 13.

Pediatric Nephrology, Rady Children's Hospital-San Diego, University of California, San Diego, San Diego, CA, USA.

Background: Ctns mice, a mouse model of infantile nephropathic cystinosis, exhibit hypermetabolism with adipose tissue browning and profound muscle wasting. Ctns mice are 25(OH)D and 1,25(OH) D insufficient. We investigated whether vitamin D repletion could ameliorate adipose tissue browning and muscle wasting in Ctns mice.

Methods: Twelve-month-old Ctns mice and wild-type controls were treated with 25(OH)D and 1,25(OH) D (75 μg/kg/day and 60 ng/kg/day, respectively) or an ethylene glycol vehicle for 6 weeks. Serum chemistry and parameters of energy homeostasis were measured. We quantitated total fat mass and studied expression of molecules regulating adipose tissue browning, energy metabolism, and inflammation. We measured lean mass content, skeletal muscle fibre size, in vivo muscle function (grip strength and rotarod activity), and expression of molecules regulating muscle metabolism. We also analysed the transcriptome of skeletal muscle in Ctns mice using RNAseq.

Results: Supplementation of 25(OH)D and 1,25(OH) D normalized serum concentration of 25(OH)D and 1,25(OH) D in Ctns mice, respectively. Repletion of vitamin D partially or fully normalized food intake, weight gain, gain of fat, and lean mass, improved energy homeostasis, and attenuated perturbations of uncoupling proteins and adenosine triphosphate content in adipose tissue and muscle in Ctns mice. Vitamin D repletion attenuated elevated expression of beige adipose cell biomarkers (UCP-1, CD137, Tmem26, and Tbx1) as well as aberrant expression of molecules implicated in adipose tissue browning (Cox2, Pgf2α, and NF-κB pathway) in inguinal white adipose tissue in Ctns mice. Vitamin D repletion normalized skeletal muscle fibre size and improved in vivo muscle function in Ctns mice. This was accompanied by correcting the increased muscle catabolic signalling (increased protein contents of IL-1β, IL-6, and TNF-α as well as an increased gene expression of Murf-2, atrogin-1, and myostatin) and promoting the decreased muscle regeneration and myogenesis process (decreased gene expression of Igf1, Pax7, and MyoD) in skeletal muscles of Ctns mice. Muscle RNAseq analysis revealed aberrant gene expression profiles associated with reduced muscle and neuron regeneration, increased energy metabolism, and fibrosis in Ctns mice. Importantly, repletion of 25(OH)D and 1,25(OH) D normalized the top 20 differentially expressed genes in Ctns mice.

Conclusions: We report the novel findings that correction of 25(OH)D and 1,25(OH) D insufficiency reverses cachexia and may improve quality of life by restoring muscle function in an animal model of infantile nephropathic cystinosis. Mechanistically, vitamin D repletion attenuates adipose tissue browning and muscle wasting in Ctns mice via multiple cellular and molecular mechanisms.
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http://dx.doi.org/10.1002/jcsm.12497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7015252PMC
February 2020

Autoinflammatory disease: New mouse models and therapies.

Authors:
Hal M Hoffman

J Allergy Clin Immunol 2020 01 30;145(1):116-118. Epub 2019 Oct 30.

Division of Pediatric Allergy, Immunology, and Rheumatology, University of California at San Diego and Rady Children's Hospital of San Diego, La Jolla, Calif. Electronic address:

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http://dx.doi.org/10.1016/j.jaci.2019.10.016DOI Listing
January 2020

Mutations in topoisomerase IIβ result in a B cell immunodeficiency.

Nat Commun 2019 08 13;10(1):3644. Epub 2019 Aug 13.

Department of Pediatrics, University of California at San Diego, La Jolla, CA, 92093, USA.

B cell development is a highly regulated process involving multiple differentiation steps, yet many details regarding this pathway remain unknown. Sequencing of patients with B cell-restricted immunodeficiency reveals autosomal dominant mutations in TOP2B. TOP2B encodes a type II topoisomerase, an essential gene required to alleviate topological stress during DNA replication and gene transcription, with no previously known role in B cell development. We use Saccharomyces cerevisiae, and knockin and knockout murine models, to demonstrate that patient mutations in TOP2B have a dominant negative effect on enzyme function, resulting in defective proliferation, survival of B-2 cells, causing a block in B cell development, and impair humoral function in response to immunization.
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http://dx.doi.org/10.1038/s41467-019-11570-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6692411PMC
August 2019

Alternative splicing regulates stochastic NLRP3 activity.

Nat Commun 2019 07 19;10(1):3238. Epub 2019 Jul 19.

Institute of Innate Immunity, University Hospital, University of Bonn, 53127, Bonn, Germany.

Leucine-rich repeat (LRR) domains are evolutionarily conserved in proteins that function in development and immunity. Here we report strict exonic modularity of LRR domains of several human gene families, which is a precondition for alternative splicing (AS). We provide evidence for AS of LRR domain within several Nod-like receptors, most prominently the inflammasome sensor NLRP3. Human NLRP3, but not mouse NLRP3, is expressed as two major isoforms, the full-length variant and a variant lacking exon 5. Moreover, NLRP3 AS is stochastically regulated, with NLRP3 ∆ exon 5 lacking the interaction surface for NEK7 and hence loss of activity. Our data thus reveals unexpected regulatory roles of AS through differential utilization of LRRs modules in vertebrate innate immunity.
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http://dx.doi.org/10.1038/s41467-019-11076-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6642158PMC
July 2019

Partial Jacobsen syndrome phenotype in a patient with a de novo frameshift mutation in the ETS1 transcription factor.

Cold Spring Harb Mol Case Stud 2019 06 3;5(3). Epub 2019 Jun 3.

Department of Pediatrics, UCSD School of Medicine, La Jolla, California 92093, USA.

Jacobsen syndrome (OMIM #147791) is a rare contiguous gene disorder caused by deletions in distal 11q. The clinical phenotype is variable and can include dysmorphic features, varying degrees of intellectual disability, behavioral problems including autism and attention deficit hyperactivity disorder, congenital heart defects, structural kidney defects, genitourinary problems, immunodeficiency, and a bleeding disorder due to impaired platelet production and function. Previous studies combining both human and animal systems have implicated several disease-causing genes in distal 11q that contribute to the Jacobsen syndrome phenotype. One gene, , has been implicated in causing congenital heart defects, structural kidney defects, and immunodeficiency. We performed a comprehensive phenotypic analysis on a patient with congenital heart disease previously found to have a de novo frameshift mutation in , resulting in the loss of the DNA-binding domain of the protein. Our results suggest that loss of causes a "partial Jacobsen syndrome phenotype" including congenital heart disease, facial dysmorphism, intellectual disability, and attention deficit hyperactivity disorder.
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http://dx.doi.org/10.1101/mcs.a004010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6549550PMC
June 2019

Differential Immune Activation in Fetal Macrophage Populations.

Sci Rep 2019 05 22;9(1):7677. Epub 2019 May 22.

Department of Pediatrics, University of California, San Diego, La Jolla, CA, Rady Children's Hospital, San Diego, San Diego, CA, USA.

Distinct macrophage subsets populate the developing embryo and fetus in distinct waves. However little is known about the functional differences between in utero macrophage populations or how they might contribute to fetal and neonatal immunity. Here we tested the innate immune response of mouse macrophages derived from the embryonic yolk sac and from fetal liver. When isolated from liver or lung, CD11b fetal liver derived macrophages responded to the TLR4 agonist LPS by expressing and releasing inflammatory cytokines. However F4/80 macrophages from the yolk sac did not respond to LPS treatment. While differences in TLR4 expression did not appear to explain these data, F4/80 macrophages had much lower NLRP3 inflammasome expression compared to CD11b macrophages. Gene expression profiling also demonstrated LPS-induced expression of inflammatory genes in CD11b macrophages, but not in F4/80 cells. Genes expressed in LPS-treated CD11b macrophages were more likely to contain predicted NF-κB binding sites in their promoter regions. Our data show that CD11b macrophages derived from fetal liver are the major pro-inflammatory cells in the developing fetus. These findings could have important implications in better understanding the fetal inflammatory response and the unique features of neonatal immunity.
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http://dx.doi.org/10.1038/s41598-019-44181-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6531440PMC
May 2019

CAPS and NLRP3.

J Clin Immunol 2019 04 10;39(3):277-286. Epub 2019 May 10.

Division of Pediatric Allergy, Immunology, and Rheumatology, Rady Children's Hospital of San Diego, University of California, San Diego, San Diego, CA, USA.

Cryopyrin-associated periodic syndrome (CAPS) is a rare inherited autoinflammatory disorder characterized by systemic, cutaneous, musculoskeletal, and central nervous system inflammation. Gain-of-function mutations in NLRP3 in CAPS patients lead to activation of the cryopyrin inflammasome, resulting in the inappropriate release of inflammatory cytokines including IL-1β and CAPS-related inflammatory symptoms. Several mechanisms have been identified that are important for the normal regulation of the cryopyrin inflammasome in order to prevent uncontrolled inflammation. Investigators have taken advantage of some of these pathways to develop and apply novel targeted therapies, which have resulted in improved quality of life for patients with this orphan disease.
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http://dx.doi.org/10.1007/s10875-019-00638-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8575304PMC
April 2019

Choline Uptake and Metabolism Modulate Macrophage IL-1β and IL-18 Production.

Cell Metab 2019 06 11;29(6):1350-1362.e7. Epub 2019 Apr 11.

Departments of Pharmacology and Pathology, University of California San Diego, La Jolla, CA, 92037, USA. Electronic address:

Choline is a vitamin-like nutrient that is taken up via specific transporters and metabolized by choline kinase, which converts it to phosphocholine needed for de novo synthesis of phosphatidylcholine (PC), the main phospholipid of cellular membranes. We found that Toll-like receptor (TLR) activation enhances choline uptake by macrophages and microglia through induction of the choline transporter CTL1. Inhibition of CTL1 expression or choline phosphorylation attenuated NLRP3 inflammasome activation and IL-1β and IL-18 production in stimulated macrophages. Mechanistically, reduced choline uptake altered mitochondrial lipid profile, attenuated mitochondrial ATP synthesis, and activated the energy sensor AMP-activated protein kinase (AMPK). By potentiating mitochondrial recruitment of DRP1, AMPK stimulates mitophagy, which contributes to termination of NLRP3 inflammasome activation. Correspondingly, choline kinase inhibitors ameliorated acute and chronic models of IL-1β-dependent inflammation.
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http://dx.doi.org/10.1016/j.cmet.2019.03.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6675591PMC
June 2019

Neutrophils: New insights and open questions.

Sci Immunol 2018 12 7;3(30). Epub 2018 Dec 7.

Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.

Neutrophils are the first line of defense against bacteria and fungi and help combat parasites and viruses. They are necessary for mammalian life, and their failure to recover after myeloablation is fatal. Neutrophils are short-lived, effective killing machines. Their life span is significantly extended under infectious and inflammatory conditions. Neutrophils take their cues directly from the infectious organism, from tissue macrophages and other elements of the immune system. Here, we review how neutrophils traffic to sites of infection or tissue injury, how they trap and kill bacteria, how they shape innate and adaptive immune responses, and the pathophysiology of monogenic neutrophil disorders.
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http://dx.doi.org/10.1126/sciimmunol.aat4579DOI Listing
December 2018

TLR Activation Alters Bone Marrow-Derived Macrophage Differentiation.

J Innate Immun 2019 8;11(1):99-108. Epub 2018 Nov 8.

Department of Pediatrics, University of California San Diego, Rady Children's Hospital, San Diego, California, USA,

Early exposure to inflammatory signals may have a lasting impact on immune function. Present throughout embryogenesis, macrophages are key cells providing innate immune protection to the developing fetus and newborn. Here, we have used an established model of macrophage development to test how early inflammatory signals can impact cellular differentiation and function. Bone marrow-derived macrophages were treated with Escherichia coli lipopolysaccharide (LPS) 2 days after initial isolation and culture. LPS treatment during this early stage of differentiation decreased the expression of CSF1R and increased that of the mature macrophage marker F4/80. These early changes in macrophage differentiation were also measured in cells from mice lacking IKKβ, but the change in CSF1R expression after LPS treatment was blocked with MAPK inhibition. LPS-induced changes in macrophage marker expression persisted following LPS removal, suggesting that early inflammatory activation could induce a lasting developmental impact. Early LPS exposure inhibited macrophage phagocytosis of labeled E. coli while LPS had no effect on fully differentiated macrophages. Our data demonstrate that early inflammatory exposure to a microbial stimulus induce lasting phenotypic changes in macrophages.
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http://dx.doi.org/10.1159/000494070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6296861PMC
February 2020

NLR Family Pyrin Domain-Containing 3 Inflammasome Activation in Hepatic Stellate Cells Induces Liver Fibrosis in Mice.

Hepatology 2019 02 3;69(2):845-859. Epub 2019 Jan 3.

Department of Pediatrics, University of California San Diego, La Jolla, CA.

The NLR family pyrin domain-containing 3 (NLRP3) inflammasome plays an important role in liver fibrosis (LF) development. However, the mechanisms involved in NLRP3-induced fibrosis are unclear. Our aim was to test the hypothesis that the NLRP3 inflammasome in hepatic stellate cells (HSCs) can directly regulate their activation and contribute to LF. Primary HSCs isolated from wild-type (WT), Nlrp3 , or Nlrp3 knock-in crossed to inducible (estrogen receptor Cre-CreT) mice were incubated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP), or 4OH-tamoxifen, respectively. HSC-specific Nlrp3 knock-in mice were generated by crossing transgenic mice expressing lecithin retinol acyltransferase (Lrat)-driven Cre and maintained on standard rodent chow for 6 months. Mice were then sacrificed; liver tissue and serum were harvested. Nlrp3 inflammasome activation along with HSC phenotype and fibrosis were assessed by RT-PCR, western blotting, fluorescence-activated cell sorting (FACS), enzyme-linked immunosorbent assay, immunofluorescence (IF), and immunohistochemistry (IHC). Stimulated WT HSCs displayed increased levels of NLRP3 inflammasome-induced reactive oxygen species (ROS) production and cathepsin B activity, accompanied by an up-regulation of mRNA and protein levels of fibrotic makers, an effect abrogated in Nlrp3 HSCs. Nlrp3 CreT HSCs also showed elevated mRNA and protein expression of fibrotic markers 24 hours after inflammasome activation induced with 4-hydroxytamoxifen (4OHT). Protein and mRNA expression levels of fibrotic markers were also found to be increased in isolated HSCs and whole liver tissue from Nlrp3 Lrat Cre mice compared to WT. Liver sections from 24-week-old Nlrp Lrat Cre mice showed fibrotic changes with increased alpha smooth muscle actin (αSMA) and desmin-positive cells and collagen deposition, independent of inflammatory infiltrates; these changes were also observed after LPS challenge in 8-week-old Nlrp Lrat Cre mice. Conclusion: Our results highlight a direct role for the NLRP3 inflammasome in the activation of HSCs directly triggering LF.
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http://dx.doi.org/10.1002/hep.30252DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6351190PMC
February 2019

In silico validation of the Autoinflammatory Disease Damage Index.

Ann Rheum Dis 2018 11 4;77(11):1599-1605. Epub 2018 Aug 4.

Paediatric Pneumology and Immunology and Interdisciplinary Centre for Social Paediatrics, Charite University Medicine Berlin, Berlin, Germany.

Introduction: Autoinflammatory diseases can cause irreversible tissue damage due to systemic inflammation. Recently, the Autoinflammatory Disease Damage Index (ADDI) was developed. The ADDI is the first instrument to quantify damage in familial Mediterranean fever, cryopyrin-associated periodic syndromes, mevalonate kinase deficiency and tumour necrosis factor receptor-associated periodic syndrome. The aim of this study was to validate this tool for its intended use in a clinical/research setting.

Methods: The ADDI was scored on paper clinical cases by at least three physicians per case, independently of each other. Face and content validity were assessed by requesting comments on the ADDI. Reliability was tested by calculating the intraclass correlation coefficient (ICC) using an 'observer-nested-within-subject' design. Construct validity was determined by correlating the ADDI score to the Physician Global Assessment (PGA) of damage and disease activity. Redundancy of individual items was determined with Cronbach's alpha.

Results: The ADDI was validated on a total of 110 paper clinical cases by 37 experts in autoinflammatory diseases. This yielded an ICC of 0.84 (95% CI 0.78 to 0.89). The ADDI score correlated strongly with PGA-damage (r=0.92, 95% CI 0.88 to 0.95) and was not strongly influenced by disease activity (r=0.395, 95% CI 0.21 to 0.55). After comments from disease experts, some item definitions were refined. The interitem correlation in all different categories was lower than 0.7, indicating that there was no redundancy between individual damage items.

Conclusion: The ADDI is a reliable and valid instrument to quantify damage in individual patients and can be used to compare disease outcomes in clinical studies.
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http://dx.doi.org/10.1136/annrheumdis-2018-213725DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8411437PMC
November 2018

CaMKIIδ-mediated inflammatory gene expression and inflammasome activation in cardiomyocytes initiate inflammation and induce fibrosis.

JCI Insight 2018 06 21;3(12). Epub 2018 Jun 21.

Department of Pharmacology.

Inflammation accompanies heart failure and is a mediator of cardiac fibrosis. CaMKIIδ plays an essential role in adverse remodeling and decompensation to heart failure. We postulated that inflammation is the mechanism by which CaMKIIδ contributes to adverse remodeling in response to nonischemic interventions. We demonstrate that deletion of CaMKIIδ in the cardiomyocyte (CKO) significantly attenuates activation of NF-κB, expression of inflammatory chemokines and cytokines, and macrophage accumulation induced by angiotensin II (Ang II) infusion. The inflammasome was activated by Ang II, and this response was also diminished in CKO mice. These events occurred prior to any evidence of Ang II-induced cell death. In addition, CaMKII-dependent inflammatory gene expression and inflammasome priming were observed as early as the third hour of infusion, a time point at which macrophage recruitment was not evident. Inhibition of either the inflammasome or monocyte chemoattractant protein 1 (MCP1) signaling attenuated macrophage accumulation, and these interventions, like cardiomyocyte CaMKIIδ deletion, diminished the fibrotic response to Ang II. Thus, activation of CaMKIIδ in the cardiomyocyte represents what we believe to be a novel mechanism for initiating inflammasome activation and an inflammatory gene program that leads to macrophage recruitment and ultimately to development of fibrosis.
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http://dx.doi.org/10.1172/jci.insight.97054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124412PMC
June 2018

JAK inhibitors in autoinflammation.

J Clin Invest 2018 07 11;128(7):2760-2762. Epub 2018 Jun 11.

Interferonopathies are a subset of autoinflammatory disorders with a prominent type I IFN gene signature. Treatment of these patients has been challenging, given the lack of response to common autoinflammatory therapeutics including IL-1 and TNF blockade. JAK inhibitors (Jakinibs) are a family of small-molecule inhibitors that target the JAK/STAT signaling pathway and have shown clinical efficacy, with FDA and European Medicines Agency (EMA) approval for arthritic and myeloproliferative syndromes. Sanchez and colleagues repurposed baricitinib to establish a significant role for JAK inhibition as a novel therapy for patients with interferonopathies, demonstrating the power of translational rare disease research with lifesaving effects.
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http://dx.doi.org/10.1172/JCI121526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025991PMC
July 2018
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