Research
Abstract
The HER2-specific monoclonal antibody (mAb), Trastuzumab, has been the mainstay of therapy for HER2+ breast cancers (BC) for ~20 years. However, its therapeutic mechanism of action (MOA) remains unclear, with antitumor responses to Trastuzumab remaining heterologous and metastatic HER2+ BC remaining incurable. Consequently, understanding its MOA could enable rational strategies to enhance its efficacy. Using both novel murine and human versions of Trastuzumab, we found its antitumor activity dependent on Fcγ-Receptor stimulation of tumor-associated-macrophages (TAM) and Antibody-Dependent-Cellular-Phagocytosis (ADCP), but not cytotoxicity (ADCC). Trastuzumab also stimulated TAM activation and expansion, but did not require adaptive immunity, natural killer cells, and/or neutrophils. Moreover, inhibition of the innate immune ADCP checkpoint, CD47, significantly enhanced Trastuzumab-mediated ADCP, TAM expansion and activation, resulting in the emergence of a unique hyper-phagocytic macrophage population, improved antitumor responses and prolonged survival. In addition, we found tumor-associated CD47 expression was inversely associated with survival in HER2+ BC patients and that human HER2+ BC xenografts treated with Trastuzumab+CD47 inhibition underwent complete tumor regression. Collectively, our study identifies Trastuzumab-mediated ADCP as a significant antitumor MOA that may be clinically enabled by CD47 blockade to augment therapeutic efficacy.
Authors
Li-Chung Tsao, Erika J. Crosby, Timothy N. Trotter, Pankaj Agarwal, Bin-Jin Hwang, Chaitanya Acharya, Casey W. Shuptrine, Tao Wang, Junping Wei, Xiao Yang, Gangjun Lei, Cong-Xiao Liu, Christopher A. Rabiola, Lewis A. Chodosh, William J. Muller, Herbert Kim Lyerly, Zachary C. Hartman
Abstract
Conventional treatments for inflammatory bowel disease (IBD) have multiple potential side effects. Therefore, alternative treatments are desperately needed. This work demonstrated that systemic administration of exosomes from human bone marrow-derived mesenchymal stromal cells (MSC-Exos) significantly mitigated colitis in various models of IBD. MSC-Exos treatment downregulated inflammatory responses, maintained intestinal barrier integrity and polarized M2b macrophages, but did not favor intestinal fibrosis. Mechanistically, infused MSC-Exos mainly acted on colonic macrophages and macrophages from colitic colons acquired obvious resistance to inflammatory re-stimulation when prepared from mice treated with MSC-Exos versus untreated mice. The beneficial effect of MSC-Exos was blocked by macrophage depletion. Besides, the induction of IL-10 production from macrophages was partially involved in the beneficial effect of MSC-Exos. MSC-Exos were enriched in proteins involved in regulating multiple biological processes associated with the anti-colitic benefit of MSC-Exos. Particularly, metallothionein-2 in MSC-Exos was required for the suppression of inflammatory responses. Taken together, MSC-Exos are critical regulators of inflammatory responses and may be promising candidates for IBD treatment.
Authors
Huashan Liu, Zhenxing Liang, Fengwei wang, Chi Zhou, Xiaobin Zheng, Tuo Hu, Xiaowen He, Xianrui Wu, Ping Lan
Abstract
γδ T cells account for a large fraction of human intestinal intraepithelial lymphocytes (IELs) endowed with potent anti-tumor activities. However, little is known about their origin, phenotype and clinical relevance in colorectal cancer (CRC). To determine γδ IEL gut-specificity, homing and functions, γδ T cells were purified from human healthy blood, lymph nodes, liver, skin, intestine either disease-free or affected by CRC or generated from thymic precursors. The constitutive expression of NKp46 specifically identifies a new subset of cytotoxic Vδ1 T cells representing the largest fraction of gut-resident IELs. The ontogeny and gut-tropism of NKp46pos/Vδ1 IELs depends both on distinctive features of Vδ1 thymic precursors and gut-environmental factors. Either the constitutive presence of NKp46 on tissue-resident Vδ1 intestinal IELs or its induced-expression on IL-2/IL-15 activated Vδ1 thymocytes are associated with anti-tumor functions. Higher frequencies of NKp46pos/Vδ1 IELs in tumor-free specimens from CRC patients correlate with a lower risk of developing metastatic III/IV disease stages. Additionally, our in vitro settings reproducing CRC tumor-microenvironment inhibited the expansion of NKp46pos/Vδ1 cells from activated thymic precursors. These results parallel the very low frequencies of NKp46pos/Vδ1 IELs able to infiltrate CRC, thus providing new insights to either follow-up cancer progression or develop novel adoptive cellular therapies.
Authors
Joanna Mikulak, Ferdinando Oriolo, Elena Bruni, Alessandra Roberto, Federico S. Colombo, Anna Villa, Marita Bosticardo, Ileana Bortolomai, Elena Lo Presti, Serena Meraviglia, Francesco Dieli, Stefania Vetrano, Silvio Danese, Silvia Della Bella, Michele M. Carvello, Matteo Sacchi, Giovanni Cugini, Giovanni Colombo, Marco Klinger, Paola Spaggiari, Massimo Roncalli, Immo Prinz, Sarina Ravens, Biagio di Lorenzo, Emanuela Marcenaro, Bruno Silva-Santos, Antonino Spinelli, Domenico Mavilio
Abstract
Rationale: Reflex-mediated sympathoexcitation is central to the pathogenesis of arrhythmias and heart disease; neuraxial modulation can favorably attenuate these cardiac reflexes leading to cardioprotection. Objective: The purpose of this study was to define the mechanism by which cardiac neural decentralization and spinal cord stimulation (SCS) reduces ischemia-induced ventricular fibrillation (VF) and sudden cardiac death (SCD) by utilizing direct neurotransmitter measurements in the heart. Methods and Results: Direct measurement of norepinephrine (NE) levels in the left ventricular (LV) interstitial fluid (ISF) by microdialysis in response to transient left anterior descending coronary artery occlusion (CAO: 15 min) in anesthetized canines. Responses were studied with: (i) intact neuraxis and were compared to those in which the (ii) intrathoracic component of the cardiac neuraxis (stellate ganglia),(iii) the intrinsic cardiac neuronal (ICN) system were surgically delinked from the central nervous system versus (iv) subjects with intact neuraxis subjected to pre-emptive SCS (T1-T3 spinal level). With an intact neuraxis, animals with exaggerated NE-ISF levels in response to CAO were at increased risk for VF and SCD. During CAO there was a 152% increase in NE level when the entire neuraxis was intact compared to 114% following intrathoracic neuraxial decentralization (removal of the stellates) and 16% increase following ICN decentralization, when the entire heart and ICN was delinked from the other levels of the neuraxis. During SCS, CAO increased NE levels by 59%. Risk for CAO-induced VF was 38% in controls, 8% following total decentralization and 11% following SCS. Conclusions: These data indicate that ischemia related afferent neuronal transmission engages central and intrathoracic sympathetic reflexes which amplifies sympathoexcitation and results in an increase in regional ventricular NE release that causes VF and SCD. Surgical decentralization or SCS prevents this amplification of sympathoexcitation, attenuating the resultant NE release, and reduces VF and SCD.
Authors
Jeffrey L. Ardell, Robert D. Foreman, J. Andrew Armour, Kalyanam Shivkumar
Abstract
At diagnosis, most people with type 1 diabetes (T1D) produce measurable levels of endogenous insulin, but the rate at which insulin secretion declines is heterogeneous. To explain this heterogeneity, we sought to identify a composite signature predictive of insulin secretion, using a collaborative assay evaluation and analysis pipeline that incorporated multiple cellular and serum measures reflecting beta cell health and immune system activity. The ability to predict decline in insulin secretion would be useful for patient stratification for clinical trial enrollment or therapeutic selection. Analytes from 12 qualified assays were measured in shared samples from subjects newly diagnosed with T1D. We developed a computational tool to identify a composite panel associated with decline in insulin secretion over 2 years after diagnosis. The tool employs multiple filtering steps to reduce data dimensionality, incorporates error-estimation techniques including cross-validation and sensitivity analysis, and is flexible to assay type, clinical outcome and disease setting. Using this novel analytical tool, we identified a panel of immune markers that, in combination, are highly associated with loss of insulin secretion. The methods used here represent a novel process for identifying combined immune signatures that predict outcomes relevant for complex and heterogeneous diseases like T1D.
Authors
Cate Speake, Samuel O. Skinner, Dror Berel, Elizabeth Whalen, Matthew J. Dufort, William Chad Young, Jared M. Odegard, Anne M. Pesenacker, Frans K. Gorus, Eddie A. James, Megan K. Levings, Peter S. Linsley, Eitan M. Akirav, Alberto Pugliese, Martin J. Hessner, Gerald T. Nepom, Raphael Gottardo, S. Alice Long
Abstract
Pulmonary drug delivery presents a unique opportunity to target lower airway inflammation, which is often characterized by the massive recruitment of neutrophils from blood. However specific therapies are lacking that can modulate airway neutrophil function, and difficult challenges must be overcome to achieve therapeutic efficacy against pulmonary inflammation, notably drug hydrophobicity, mucociliary and macrophage-dependent clearance, and high extracellular protease burden. Here, we present a multi-stage, aerodynamically favorable delivery platform that uses extracellular proteolysis to its advantage in order to deliver nanoparticle-embedded hydrophobic drugs to neutrophils within the lower airways. Our design consists in a self-regulated nanoparticle-in-microgel system, in which microgel activation is triggered by extracellular elastase (degranulated by inflammatory neutrophils), and nanoparticles are loaded with Nexinhib20, a potent neutrophil degranulation inhibitor. Successful in vivo delivery of Nexinhib20 to the airways and into neutrophils promoted resolution of the inflammatory response by dampening neutrophil recruitment and degranulation, pro-inflammatory cytokine production in both airway and systemic compartments, as well as the presence of neutrophil-derived pathological extracellular vesicles in the lung fluid. Our findings showcase a new platform that overcomes challenges in pulmonary drug delivery and allows customization to match the proteolytic footprint of given diseases.
Authors
Joscelyn C Mejías, Osric A Forrest, Camilla Margaroli, David A. Frey Rubio, Liliana Viera, Jindong Li, Xin Xu, Amit Gaggar, Rabindra Tirouvanziam, Krishnendu Roy
Abstract
Gonorrhea is a sexually transmitted infection with 87 million new cases per year globally. Increasing antibiotic resistance has severely limited treatment options. A mechanism that Neisseria gonorrhoeae uses to evade complement attack is binding of the complement inhibitor C4b-binding protein (C4BP). We screened 107 PorB1a and 83 PorB1b clinical isolates randomly selected from a Swedish strain collection over the last 10 years and noted that 96/107 (89.7%) PorB1a and 16/83 (19.3%) PorB1b bound C4BP; C4BP binding significantly correlated with the ability to evade complement-dependent killing (r = 0.78; p<0.0001). We designed two chimeric proteins that fused C4BP domains to the backbone of immunoglobulins IgG or IgM (C4BP-IgG; C4BP-IgM) with the aim of enhancing complement activation and killing of gonococci. Both proteins bound gonococci (Kd C4BP-IgM = 2.4 nM; Kd C4BP-IgG 981 nM), but only hexameric C4BP-IgM efficiently out-competed heptameric C4BP from bacterial surface resulting in enhanced complement deposition and bacterial killing. Furthermore, C4BP-IgM significantly attenuated the duration and burden of colonization of two C4BP-binding gonococcal isolates, but not a C4BP non-binding strain in the mouse vaginal colonization model using human factor H/C4BP transgenic mice. Our pre-clinical data present C4BP-IgM as an adjunctive to conventional antimicrobials for the treatment of gonorrhea.
Authors
Serena Bettoni, Jutamas Shaughnessy, Karolina Maziarz, David Ermert, Sunita Gulati, Bo Zheng, Matthias Mörgelin, Susanne Jacobsson, Kristian Riesbeck, Magnus Unemo, Sanjay Ram, Anna M. Blom
Abstract
Mitochondrial quality control (MQC) is crucial for regulating central nervous system homeostasis and its disruption has been implicated in the pathogenesis of some of the most common neurodegenerative diseases. In healthy tissues, the maintenance of MQC depends upon an exquisite balance between mitophagy (removal of damaged mitochondria by autophagy) and biogenesis (de-novo synthesis of mitochondria). Here, we show that mitophagy is disrupted in diabetic retinopathy (DR) and decoupled from mitochondrial biogenesis during the progression of the disease. Diabetic retinas from human post-mortem donors and experimental mice exhibit a net loss of mitochondrial contents during the early stages of the disease process. Using novel diabetic mitophagy-reporter mice (mitoQC-Ins2Akita) alongside pMitoTimer (a molecular clock to address mitochondrial-age dynamics), we demonstrate that mitochondrial loss arose due to an inability of mitochondrial biogenesis to compensate for diabetes-exacerbated mitophagy. However, as diabetes duration increases, Pink1-dependent mitophagy deteriorates, leading to the build-up of mitochondria primed for degradation in DR. Impairment of mitophagy during prolonged diabetes is linked with the development of retinal senescence, a phenotype that blunted hyperglycaemia-induced mitophagy in mitoQC primary Müller cells. Our findings suggest that normalizing mitochondrial turnover may preserve MQC and provide novel therapeutic options for the management of DR-associated complications.
Authors
Jose R. Hombrebueno, Lauren Cairns, Louise R. Dutton, Timothy J. Lyons, Derek P. Brazil, Paul Moynagh, Tim M. Curtis, Heping Xu
Abstract
Diabetic foot ulcers (DFUs) are a life-threatening disease that often result in lower limb amputations and a shortened lifespan. Current treatment options are limited and often not efficacious, raising the need for new therapies. To investigate the therapeutic potential of topical statins to restore healing in patients with DFUs, we performed next generation sequencing on mevastatin-treated primary human keratinocytes. We found that mevastatin activated and modulated the EGF signaling to trigger an anti-proliferative and pro-migratory phenotype, suggesting that statins may shift DFUs from a hyper-proliferative phenotype to a pro-migratory phenotype in order to stimulate healing. Furthermore, mevastatin induced a migratory phenotype in primary human keratinocytes through EGF-mediated activation of Rac1, resulting in actin cytoskeletal reorganization and lamellipodia formation. Interestingly, the EGF receptor is downregulated in tissue biopsies from patients with DFUs. Mevastatin restored EGF signaling in DFUs through disruption of caveolae to promote keratinocyte migration, which was confirmed by caveolin-1 (Cav1) overexpression studies. We conclude that topical statins may have considerable therapeutic potential as a treatment option for patients with DFUs and offer an effective treatment for chronic wounds that can be rapidly translated to clinical use.
Authors
Andrew P. Sawaya, Ivan Jozic, Rivka C. Stone, Irena Pastar, Andjela N. Egger, Olivera Stojadinovic, George D. Glinos, Robert S. Kirsner, Marjana Tomic-Canic
Abstract
Muscle contractures are a prominent and disabling feature of many neuromuscular disorders, including the two most common forms of childhood neurologic dysfunction: neonatal brachial plexus injury (NBPI) and cerebral palsy (CP). There are currently no treatment strategies to directly alter the contracture pathology, as the pathogenesis of these contractures is unknown. We previously showed in a mouse model of NBPI that contractures result from impaired longitudinal muscle growth. Current presumed explanations for growth impairment in contractures focus on the dysregulation of muscle stem cells (MuSCs), which differentiate and fuse to existing myofibers during growth, as this process has classically been thought to control muscle growth during the neonatal period. Here, we demonstrate in a mouse model of NBPI that denervation does not prevent myonuclear accretion and that reduction of myonuclear number has no effect on functional muscle length or contracture development, providing definitive evidence that altered myonuclear accretion is not a driver of neuromuscular contractures. In contrast, we observed elevated levels of protein degradation in NBPI muscle, and we demonstrate that contractures can be pharmacologically prevented with the proteasome inhibitor, bortezomib. These studies provide the first strategy to prevent neuromuscular contractures by correcting the underlying deficit in longitudinal muscle growth.
Authors
Sia Nikolaou, Alyssa A.W. Cramer, Liangjun Hu, Qingnian Goh, Douglas P. Millay, Roger Cornwall
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