Andrew Baird

• PhD
• Professor (Full) at University of California, San Diego

In light of the central role of inflammation in normal wound repair and regeneration, we hypothesize that the preponderance of human-specific genes expressed in human inflammatory cells is commensurate with the genetic versatility of inflammatory response and the emergence of injuries associated with uniquely hominid behaviors, like a bipedal postu...

Conventional wisdom presumes that the α7nAChR product of CHRNA7 expression mediates the ability of the vagus nerve to regulate the inflammatory response to injury and infection. Yet, 15 years ago, a 2nd structurally distinct and human-specific α7nAChR gene was discovered that has largely escaped attention of the inflammation research community. The...

The two major mitogenic polypeptides for endothelial cells have been purified to homogeneity. The complete primary structure of bovine pituitary basic fibroblast growth factor (FGF) and the amino-terminal amino acid sequence of bovine brain acidic FGF have been established by gas-phase sequence analyses. Homogeneous preparations of these polypeptid...

Mice engrafted with human CD34+ hematopoietic stem and progenitor cells (CD34+-HSPCs) have been used to study human infection, diabetes, sepsis and burn, suggesting that they could be highly amenable to characterizing the human inflammatory response to injury. To this end, we analyzed human leukocytes infiltrating subcutaneous implants of polytetra...

Background: The α7-subunit of the α7-nicotinic acetylcholine receptor (α7-nAChR) is an obligatory intermediate for the anti-inflammatory effects of the vagus nerve. But in humans, there exists a second gene called CHRFAM7A that encodes a dominant negative α7-nAChR inhibitor. Here, we investigated whether their expression was altered in inflammatory...

Otitis media (OM), the most common disease of childhood, is typically characterized by bacterial infection of the middle ear (ME). Prominent features of OM include hyperplasia of the ME mucosa, which transforms from a monolayer of simple squamous epithelium with minimal stroma into a full-thickness respiratory epithelium in 2–3 days after infection...

Objective and designCHRFAM7A is a unique human gene that encodes a dominant negative inhibitor of the α7 nicotinic acetylcholine receptor. We have recently shown that CHRFAM7A is expressed in human leukocytes, increases cel–cell adhesion, and regulates the expression of genes associated with leukocyte migration.MaterialHuman THP-1, RAW264.7 and HEK...

Introduction CHRFAM7A is a uniquely human gene that is a dominant negative inhibitor of the alpha-7 nicotinic acetylcholine receptor (a7nAchR). The relative balance of CHRFAM7A and a7nAchR expression may play an important role in mediating the human immune response to injury. We have previously shown that CHRFAM7A expression increased the hematopoi...

The complex molecular microenvironment of the wound bed regulates the duration and degree of inflammation in the wound repair process, while its dysregulation leads to impaired healing. Understanding factors controlling this response provides therapeutic targets for inflammatory disease. Esophageal cancer–related gene 4 (ECRG4) is a candidate chemo...

The embedding of small peptide ligands within large inactive pre-pro-precursor proteins encoded by orphan open reading frames (ORFs) makes them difficult to identify and study. To address this problem, we generated oligonucleotide (< 100–400 base pair) combinatorial libraries from either the epidermal growth factor (EGF) ORF that encodes the > 1200...

Significance The emergence of uniquely human genes during hominid speciation enabled numerous human-specific adaptations that presumably included changes in resilience to disease but potentially increased susceptibility as well. Here we show that the transgenic expression of one such gene, called CHRFAM7A, changes the mouse reservoir of hematopoiet...

Healthy repair of cutaneous injury is a coordinated response of inflammatory cells, secreted factors, and biologically active extracellular vesicles (EVs). Although constitutive release of EVs into biologic fluids is a hallmark of cultured cells and tumors, their payload and biologic activity appears to be tightly regulated. We show that Tre‐2/Bub2...

Background The roles of the choroid plexus (CP) and cerebrospinal fluid (CSF) production have drawn increasing attention in Alzheimer’s disease (AD) research. Specifically, studies document markedly decreased CSF production and turnover in moderate-to-severe AD. Moreover, reduced CP function and CSF turnover lead to impaired clearance of toxic meta...

Introduction: CHRFAM7A is a uniquely-human gene that encodes a human-specific variant of the alpha-7 nicotinic acetylcholine receptor (α7nAchR). While the homopentameric α7nAChR consists of 5 equal subunits, previous studies demonstrated that CHRFAM7A expression disrupts the formation of α7nAChR homopentamers. Here we use a rat neuronal cell line...

Background: Trauma/hemorrhagic shock (T/HS) causes a release of proinflammatory mediators into the mesenteric lymph (ML) that may trigger a systemic inflammatory response and subsequent organ failure. Recently, we showed that exosomes in postshock ML are biologically active mediators of this inflammation. Because the specific inflammatory mediator...

Abstract Background In Alzheimer’s disease, there are striking changes in CSF composition that relate to altered choroid plexus (CP) function. Studying CP tissue gene expression at the blood–cerebrospinal fluid barrier could provide further insight into the epithelial and stromal responses to neurodegenerative disease states. Methods Transcriptome-...

Introduction: Exosomes are extracellular vesicles that act as endogenous mediators of the immune response. We have previously shown that exosomes released into mesenteric lymph (ML) following trauma/hemorrhagic shock (T/HS) induce pro-inflammatory cytokine production in macrophages and are involved in the pathogenesis of post-shock acute lung inju...

Acute lung injury (ALI) is a common cause of morbidity in patients after severe injury due to dysregulated inflammation, which is believed to be driven by gut-derived inflammatory mediators carried via mesenteric lymph (ML). We have previously demonstrated that nano-sized extracellular vesicles, called exosomes, secreted into ML after trauma/hemorr...

The blood brain barrier (BBB) is a highly selective permeability barrier, composed of endothelial cells with tight intercellular junctions, surrounded by a basal lamina, astrocytes, and pericytes, which regulates the entry of compounds and cells between the blood and brain. The integrity of the BBB is necessary for maintaining brain function, where...

Otitis media (OM) is a common pediatric disease for which systemic antibiotics are often prescribed. While local treatment would avoid the systemic treatment side-effects, the tympanic membrane (TM) represents an impenetrable barrier unless surgically breached. We hypothesized that the TM might harbor innate biological mechanisms that could mediate...

Expression of the orphan C2orf40 gene is associated with the aggregation of the neurofibrillary tangle-protein tau in transgenic mice, tumor suppression, the induction of senescence in CNS, and the activation of microglia and peripheral mononuclear leukocytes. This gene also encodes several secreted pro- and anti-inflammatory neuropeptide-like cyto...

Background: We identified recently esophageal cancer related gene-4 (ECRG4) as a candidate cytokine that is expressed on the surface of quiescent polymorphonuclear leukocytes (PMNs) and shed in response to ex vivo treatment with lipopolysaccharide. To investigate the potential biologic relevance of changes in cell surface ECRG4 in human samples, w...

The human genome contains a variant form of the α7-nicotinic acetylcholine receptor (α7nAChR) gene that is uniquely human. This CHRFAM7A gene arose during human speciation and recent data suggests that its expression alters ligand tropism of the normally homopentameric human α7-AChR ligand-gated cell surface ion channel that is found on the surface...

The blood brain barrier (BBB) is often regarded as a passive barrier that protects brain parenchyma from toxic substances, circulating leukocytes, while allowing the passage of selected molecules. Recently, a combination of molecular profiling techniques have characterized the constituents of the BBB based on in vitro models using isolated endothel...

The human genome contains a unique, distinct, and human-specific α7-nicotinic acetylcholine receptor (α7nAChR) gene [CHRNA7 (gene-encoding α7-nicotinic acetylcholine receptor)] called CHRFAM7A (gene-encoding dup-α7-nicotinic acetylcholine receptor) on a locus of chromosome 15 associated with mental illness, including schizophrenia. Located 59 upstr...

Objective and design: The human c2orf40 gene encodes a tumor suppressor gene called esophageal cancer-related gene-4 (ECRG4) with pro- and anti-inflammatory activities that depend on cell surface processing. Here, we investigated its physical and functional association with the innate immunity receptor complex. Methods: Interactions between ECRG...

Purpose: The human c2orf40 gene encodes a candidate tumor suppressor called Esophageal Cancer-Related Gene-4 (ECRG4) that is a cytokine-like epigenetically-regulated protein that is characteristically downregulated in cancer, injury, inflammation, and infection. Here, we asked whether ECRG4 gene expression is detectable in lung epithelial cells an...

Background: Extensive infiltration of brain tumors by microglia and macrophages is a hallmark of tumor progression, and yet the overall tumor microenvironment is characterized by an immunosuppressive phenotype. Here we identify esophageal cancer-related gene 4 (Ecrg4) as a novel thrombin-processed monocyte chemoattractant that recruits myeloid cel...

To develop an animal model of injury that more closely represents the human inflammatory cell response to injury. Because the mouse inflammatory response to burn injury cannot account for the contribution of human-specific genes, animal models are needed to more closely recapitulate the human inflammatory response and improve the translational impa...

In humans, esophageal cancer-related gene 4 (ECRG4) is encoded by four exons in the c2orf40 locus of chromosome 2. Translation of ECRG4 messenger ribonucleic acid produces a 148 amino acid-secreted 17 KDa protein that is then processed to 14, ten, eight, six, four, and two KDa peptides, depending on the cell in which the gene is expressed. As hyper...

Objective Otitis media is one of the most common pediatric infections. While it is usually treated without difficulty, up to 20% of children may progress to long-term complications that include hearing loss, impaired speech and language development, academic underachievement, and irreversible disease. Hyperplasia of middle ear mucosa contributes to...

Tumor-associated microglia generally promote tumor invasion, adopting an immunosuppressive phenotype that is distinct from their pro-inflammatory functions. Based on bioinformatic mining of novel sentinel genes encoding biologically active peptides, we have recently identified Ecrg4, as a novel secreted pro-inflammatory mediator of macrophage activ...

Current antiangiogenic therapies have led to the observation that such agents can lead to improved tumor vessel structure and function termed "vascular normalization" which reduces tumor burden. However, vessel normalization is a transient process, and patients often develop resistance/poor response to anti-vascular strategies that remains an impor...

We report an inverse relationship between expression of the orphan candidate tumor suppressor gene esophageal cancer related gene 4 (Ecrg4), and the mucosal epithelial cell response to infection in the middle ear (ME). First, we found constitutive Ecrg4 mRNA expression in normal, quiescent ME mucosa that was confirmed by immunostainning of mucosal...

Overview of epithelial markers gene expression after NTHi inoculation. A survey of several well characterized epithelial markers showed that there was no down-regulation of any of these genes in the middle ear mucosa in correlation to Ecrg4 gene expression during the same time course. (DOCX)

Sentinel factors expressed on circulating cells monitor homeostasis and may initiate inflammatory signaling after injury. We identified Esophageal Cancer Related Gene‐4 (Ecrg4) as a candidate sentinel factor that resides on the surface of quiescent polymorphonuclear cells (PMNs) and responds to injury by releasing Ecrg4 protein from the cell surfac...

A review of therapeutic effects in preclinical and clinical studies suggests that concordance between large animal (pig=78%), small laboratory animal (53%) and in vitro (57%) results with those observed in humans is only partial. Pig models of wound healing provide major advantages over other animal models. Since the vast majority of wound-healing...

The Esophageal cancer-related gene-4 (Ecrg4) is a candidate tumor suppressor gene whose secreted protein product has been implicated in the development and progression of epithelial cancers, neuroprogenitor cell activation after central nervous system injury, cell senescence in neurodegeneration, and the survival of hematopoietic stem cells. Here,...

Recent studies have shown that vagus nerve stimulation (VNS) can block the burn-induced systemic inflammatory response (SIRS). In this study we examined the potential for VNS to modulate vascular permeability (VP) in local sites (i.e. skin) and in secondary sites (i.e. lung) following burn. In a 30% total body surface area burn model, VP was measur...

Large surface area burn injuries lead to activation of the innate immune system, which can be blocked by parasympathetic inputs mediated by the vagus nerve. We hypothesized that vagal nerve stimulation (VNS) would alter the inflammatory response of peritoneal macrophages after severe burn injury. Male BALB/c mice underwent right cervical VNS before...

The human open reading frame C2orf40 encodes esophageal cancer-related gene-4 (Ecrg4), a newly recognized neuropeptide-like precursor protein whose gene expression by cells in vitro, over-expression in mice in vivo, and knock-down in zebrafish affects cell proliferation, migration and senescence, progenitor cell survival and differentiation, and in...

Mucosal membranes play an important role in innate and adaptive immunity acting as physical and biological barriers that prevent and regulate the response to infections. Using whole‐genome gene arrays, we identified a small number of regulatory genes that are differentially expressed during otitis media (OM), a mucosal epithelial proliferative resp...

Objective These studies aimed to use phage display to identify hidden ligands and ligand‐domains in orphan ORF of genes of the human secretome. Methods Libraries containing 100–200 base pair fragments were generated by random fragmentation of either the 4.5 Kb human epidermal growth factor (EGF) or the 0.5Kb human ECRG4 ORF using DNase I. DNA frag...

In light of data implicating the secreted precursor protein and candidate tumor suppressor Ecrg4 in the inflammatory response, we explored the possibility that predicted ligand domains in its primary sequence can target the innate immunity receptor complex. Predicted fragments of Ecrg4 were displayed on M13 phage and tested for internalization into...

Objective To study the processing of human Ecrg4 in epithelial cells. Methods Plasmids encoding human Ecrg4, Ecrg4 mutants and Ecrg4‐derived peptides fused with green fluorescent protein were transiently expressed in the prostate cancer (PC‐3) or human embryonic kidney (HEK) epithelial cells. The expression of Ecrg4 was analyzed by immunoblotting,...

Although basic fibroblast growth factor (FGF2) was the first pro-angiogenic molecule discovered, it has numerous activities on the growth and differentiation of non-vascular cell types. FGF2 is both stimulatory and inhibitory, depending on the cell type evaluated, the experimental design used and the context in which it is tested. Here, we investig...

We identified fresh human leukocytes as an abundant source of the candidate epithelial tumor suppressor gene, Ecrg4, an epigenetically regulated gene, which unlike other tumor suppressor genes, encodes an orphan-secreted, ligand-like protein. In human cell lines, Ecrg4 gene expression was low, Ecrg4 protein undetectable, and Ecrg4 promoter hypermet...

We have recently demonstrated the protective effects of electrical stimulation of the vagus nerve in prevention of gut injury after severe burn. Here we evaluate the potential for a pharmacologic agonist of the vagus nerve as an approach to regulate outcomes in preclinical models. We tested a new generation of guanylhydrazone-derived compounds, CPS...

Drug delivery to the central nervous system requires the use of specific portals to enable drug entry into the brain and, as such, there is a growing need to identify processes that can enable drug transfer across both blood-brain and blood-cerebrospinal fluid barriers. Phage display is a powerful combinatorial technique that identifies specific pe...

By virtue of its ability to regulate the composition of cerebrospinal fluid (CSF), the choroid plexus (CP) is ideally suited to instigate a rapid response to traumatic brain injury (TBI) by producing growth regulatory proteins. For example, Esophageal Cancer Related Gene-4 (Ecrg4) is a tumor suppressor gene that encodes a hormone-like peptide calle...

INTRODUCTION Phage vectors, because of their genetic simplicity, are uniquely suited to methods that use directed evolution to genetically optimize vectors for therapeutic gene delivery. Moreover, because phage production is restricted to strain-specific bacteria, the hosts are equally amenable to genetic engineering, modification, and even genetic...

The blood-brain barrier (BBB) is a multicellular vascular structure separating blood from the brain parenchyma that is composed of endothelial cells with tight intercellular junctions, surrounded by a basal lamina, astrocytes, and pericytes. Previous studies have generated detailed databases of the microvessel transcriptome; however, less informati...

The purpose of this study was to assess acute lung injury when protection to the gut mucosal barrier offered by vagus nerve stimulation is eliminated by an abdominal vagotomy. Male balb/c mice were subjected to 30% total body surface area steam burn with and without electrical stimulation to the right cervical vagus nerve. A cohort of animals were...

The characterization of molecular responses following cerebral ischemia-induced changes in animal models capable of undergoing real-time analysis is an important goal for stroke research. In this study, we use transgenic mice to examine the activation of two different promoters in a firefly luciferase reporter mouse analyzable through a non-invasiv...

The normal blood-brain barrier (BBB) consists of tight interendothelial cell junctions and adjacent astrocyte end feet separated by a basal lamina surrounding the endothelium. The interactions between the different cell types of BBB are disrupted in distinct patterns in the microenvironment of glioma. Malignant gliomas infiltrate the surrounding no...

Vagal nerve stimulation (VNS) can have a marked anti-inflammatory effect. We have previously shown that preinjury VNS prevented intestinal barrier breakdown and preserved epithelial tight junction protein expression. However, a pretreatment model has little clinical relevance for the care of the trauma patient. Therefore, we postulated that VNS con...

Traumatic brain injury (TBI) releases a cascade of inflammatory cytokines. Vagal nerve stimulation (VNS) and ghrelin have known anti-inflammatory effects; furthermore, ghrelin release is stimulated by acetylcholine. We hypothesized VNS decreases post-TBI inflammation through a ghrelin-mediated mechanism. TBI was created in five groups of mice: sham...

The natural response to injury is dynamic and normally consists of complex temporal and spatial cellular changes in gene expression, which, when acting in synchrony, result in patent tissue repair and, in some instances, regeneration. However, current therapeutic regiments are static and most rely on matrices, gels and engineered skin tissue. Accor...

The role of the Toll-like receptor 4 (TLR4), a component of the innate immune system, in the development of burn-induced acute lung injury (ALI) has not been completely defined. Recent data suggested that an intact TLR4 plays a major role in the development of organ injury in sterile inflammation. We hypothesized that burn-induced ALI is a TLR4-dep...

Spatial distribution of host-mediated astrogliosis. A movie of 3D reconstruction of fluorescent (RFP-labeled tumor) and bioluminescent sources (GFAP activity, luciferase) in tumor-bearing GFAP-luc mice after a four-week incubation is shown.

CNS injury including stroke, infection, and tumor growth lead to astrogliosis, a process that involves upregulation of glial fibrillary acidic protein (GFAP) in astrocytes. However, the kinetics of astrogliosis that is related to these insults (i.e. tumor) is largely unknown. Using transgenic mice expressing firefly luciferase under the regulation...

The content and composition of cerebrospinal fluid (CSF) is determined in large part by the choroid plexus (CP) and specifically, a specialized epithelial cell (CPe) layer that responds to, synthesizes, and transports peptide hormones into and out of CSF. Together with ventricular ependymal cells, these CPe relay homeostatic signals throughout the...

Because the choroid plexus (CP) is uniquely suited to control the composition of cerebrospinal fluid (CSF), there may be therapeutic benefits to increasing the levels of biologically active proteins in CSF to modulate central nervous system (CNS) functions. To this end, we sought to identify peptides capable of ligand-mediated targeting to CP epith...

The blood-brain barrier (BBB) is a monolayer of endothelial cells that is regulated by the proximity of a unique basement membrane and a tightly controlled molecular interaction between specialized subsets of cells including pericytes, astrocytes, and neurons. Working together, these cells form a neurovascular unit (NVU) that is dedicated to the lo...