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The present study investigated maternal coping behaviors in clinically anxious and control mothers during two mildly stressful parent-child interaction tasks. We hypothesized that anxious mothers would demonstrate decreased problem-focused and increased emotionfocused coping. We further expected that children of anxious mothers would also demonstrate decreased problem-focused coping, and that maternal anxiety would predict child coping. A total of 49 mother-child dyads participated in the present study. Anxious mothers engaged in significantly less adaptive coping (i.e., active coping, modeling) and significantly greater maladaptive coping (i.e., venting of emotion, negative emotion, discussion of emotion) than did non-anxious mothers. In addition, anxious mothers were rated by independent observers as less able to cope with the tasks. Children of the two groups did not differ with respect to type of coping displayed. Implications of these findings for the impact of parental anxiety on children are discussed, and directions for future research are proposed. [ABSTRACT FROM AUTHOR]

Although next-generation sequencing has enabled diagnoses for many patients with Mendelian disorders, the majority remain undiagnosed. Here, we present a sibling pair who were clinically diagnosed with Escobar syndrome, however targeted gene testing was negative. Exome sequencing (ES), and later genome sequencing (GS), revealed compound heterozygous TTN variants in both siblings, a maternally inherited frameshift variant [(NM_133378.4):c.36812del; p.(Asp12271Valfs*10)], and a paternally inherited missense variant [(NM_133378.4):c.12322G > A; p.(Asp4108Asn)]. This result was considered nondiagnostic due to poor clinical fit and limited pathogenicity evidence for the missense variant of uncertain significance (VUS). Following initial nondiagnostic RNA sequencing (RNAseq) on muscle and further pursuit of other variants detected on the ES/GS, a reanalysis of noncanonical splice sites in the muscle transcriptome identified an out-of-frame exon retraction in TTN, near the known VUS. Interim literature included reports of patients with similar TTN variants who had phenotypic concordance with the siblings, and a diagnosis of a congenital titinopathy was given 4 years after the TTN variants had been initially reported. This report highlights the value of reanalysis of RNAseq with a different approach, expands the phenotypic spectrum of congenital titinopathy and also illustrates how a perceived phenotypic mismatch, and failure to consider known variants, can result in a prolongation of the diagnostic journey., (© 2024 Wiley Periodicals LLC.)

The survival of infantile-onset Pompe disease (IOPD) patients has improved dramatically since the introduction of enzyme replacement therapy (ERT) with a1glucosidase alfa. However, long-term IOPD survivors on ERT demonstrate motor deficits indicating that current therapy cannot completely prevent disease progression in skeletal muscle. We hypothesized that in IOPD, skeletal muscle endomysial stroma and capillaries would show consistent changes that could impede the movement of infused ERT from blood to muscle fibers. We retrospectively examined 9 skeletal muscle biopsies from 6 treated IOPD patients using light and electron microscopy. We found consistent ultrastructural endomysial stromal and capillary changes. The endomysial interstitium was expanded by lysosomal material, glycosomes/glycogen, cellular debris, and organelles, some exocytosed by viable muscle fibers and some released on fiber lysis. Endomysial scavenger cells phagocytosed this material. Mature fibrillary collagen was seen in the endomysium, and both muscle fibers and endomysial capillaries showed basal laminar reduplication and/or expansion. Capillary endothelial cells showed hypertrophy and degeneration, with narrowing of the vascular lumen. Ultrastructurally defined stromal and vascular changes likely constitute obstacles to movement of infused ERT from capillary lumen to muscle fiber sarcolemma, contributing to the incomplete efficacy of infused ERT in skeletal muscle. Our observations can inform approaches to overcoming these barriers to therapy., (© The Author(s) 2023. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Patients with glioblastoma (GBM) have limited options and require novel approaches to treatment. Here, we studied and deployed nonfreezing "cytostatic" hypothermia to stunt GBM growth. This growth-halting method contrasts with ablative, cryogenic hypothermia that kills both neoplastic and infiltrated healthy tissue. We investigated degrees of hypothermia in vitro and identified a cytostatic window of 20° to 25°C. For some lines, 18 hours/day of cytostatic hypothermia was sufficient to halt division in vitro. Next, we fabricated an experimental tool to test local cytostatic hypothermia in two rodent GBM models. Hypothermia more than doubled median survival, and all rats that successfully received cytostatic hypothermia survived their study period. Unlike targeted therapeutics that are successful in preclinical models but fail in clinical trials, cytostatic hypothermia leverages fundamental physics that influences biology broadly. It is a previously unexplored approach that could provide an additional option to patients with GBM by halting tumor growth.

Post-zygotically acquired genetic variants, or somatic variants, that arise during cortical development have emerged as important causes of focal epilepsies, particularly those due to malformations of cortical development. Pathogenic somatic variants have been identified in many genes within the PI3K-AKT-mTOR-signalling pathway in individuals with hemimegalencephaly and focal cortical dysplasia (type II), and more recently in SLC35A2 in individuals with focal cortical dysplasia (type I) or non-dysplastic epileptic cortex. Given the expanding role of somatic variants across different brain malformations, we sought to delineate the landscape of somatic variants in a large cohort of patients who underwent epilepsy surgery with hemimegalencephaly or focal cortical dysplasia. We evaluated samples from 123 children with hemimegalencephaly (n = 16), focal cortical dysplasia type I and related phenotypes (n = 48), focal cortical dysplasia type II (n = 44), or focal cortical dysplasia type III (n = 15). We performed high-depth exome sequencing in brain tissue-derived DNA from each case and identified somatic single nucleotide, indel and large copy number variants. In 75% of individuals with hemimegalencephaly and 29% with focal cortical dysplasia type II, we identified pathogenic variants in PI3K-AKT-mTOR pathway genes. Four of 48 cases with focal cortical dysplasia type I (8%) had a likely pathogenic variant in SLC35A2. While no other gene had multiple disease-causing somatic variants across the focal cortical dysplasia type I cohort, four individuals in this group had a single pathogenic or likely pathogenic somatic variant in CASK, KRAS, NF1 and NIPBL, genes previously associated with neurodevelopmental disorders. No rare pathogenic or likely pathogenic somatic variants in any neurological disease genes like those identified in the focal cortical dysplasia type I cohort were found in 63 neurologically normal controls (P = 0.017), suggesting a role for these novel variants. We also identified a somatic loss-of-function variant in the known epilepsy gene, PCDH19, present in a small number of alleles in the dysplastic tissue from a female patient with focal cortical dysplasia IIIa with hippocampal sclerosis. In contrast to focal cortical dysplasia type II, neither focal cortical dysplasia type I nor III had somatic variants in genes that converge on a unifying biological pathway, suggesting greater genetic heterogeneity compared to type II. Importantly, we demonstrate that focal cortical dysplasia types I, II and III are associated with somatic gene variants across a broad range of genes, many associated with epilepsy in clinical syndromes caused by germline variants, as well as including some not previously associated with radiographically evident cortical brain malformations., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Importance: Radiation necrosis (RN) is a rare but serious adverse effect following treatment with radiation therapy. No standard of care exists for the management of RN, and efforts to prevent and treat RN are limited by a lack of insight into the pathomechanics and molecular drivers of RN. This case series describes the outcomes of treatment with bevacizumab (BV) in two primary CNS lymphoma (PCNSL) patients who developed symptomatic biopsy-proven RN after whole brain radiation (WBRT) with a stereotactic radiosurgery (SRS) boost., Observations: Patient 1 is a 52 year-old female with PCNSL treated with WBRT followed by an SRS boost. She developed symptomatic biopsy-proven RN, and initial treatment with tocopherol and pentoxifylline was unsuccessful. A 100% clinical and radiographic response was achieved with 4 cycles of BV. Patient 2, a 48 year-old male with PCNSL, presented with seizures and biopsy-proven RN after radiation therapy. Initial empiric treatment with tocopherol and pentoxifylline was unsuccessful. A 100% clinical and radiographic response was achieved with 3 cycles of BV., Conclusions and Relevance: Monitoring for RN in patients with PCNSL treated with radiation therapy is warranted. BV is an efficacious treatment and a viable alternative to corticosteroids or surgical intervention., Competing Interests: CONFLICTS OF INTEREST Authors have no conflicts of interest to declare., (Copyright: © 2022 Vaios et al.)

Glomerular diseases (GDs) are a major cause of chronic kidney disease in children. The conventional approach to diagnosis of GDs includes clinical evaluation and, in most cases, kidney biopsy to make a definitive diagnosis. However, in many cases, clinical presentations of different GDs can overlap, leading to uncertainty in diagnosis and management even after renal biopsy. In this report, we identify a family with clinical diagnoses of postinfectious glomerulonephritis and IgA nephropathy in a parent and two children. Renal biopsies were initially inconclusive; however, genetic testing showed that the two individuals diagnosed at different points with IgA nephropathy carried novel segregating pathogenic variants in COL4A5 gene. We were only able to make the final diagnoses in each of the family members after genetic testing and reverse phenotyping. This case highlights the utility of genetic testing and reverse phenotyping in resolving clinical diagnosis in families with unusual constellations of different glomerulopathies. We propose that clustering of different glomerular disease phenotypes in a family should be an indication for genetic testing followed by reverse phenotyping., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kumar, Keskinyan, Stangl, Lane, Buckley, Barisoni, Howell and Gbadegesin.)

Introduction: Intraoperative neuromonitoring (IONM) is commonly used during surgery of the spine and spinal cord for early surveillance of iatrogenic injury to the central and peripheral nervous system. However, for infants and young children under 3 years of age, the use of IONM is challenging due to incomplete central and peripheral myelination., Case Presentation: We report a case of a T4-T6 dermal sinus tract (DST) that was resected on day of life 23, with the successful use of IONM., Conclusion: To our knowledge, this is the youngest reported case of the use of IONM in the surgical correction of a DST in a neonatal patient. This case demonstrates the potential efficacy of IONM in neonatal spine surgery and the techniques used to adapt the technology to an immature nervous system., (© 2022 S. Karger AG, Basel.)

Glomerular podocytes play a key role in proteinuric diseases. Accumulating evidence suggests that cGMP signaling has podocyte protective effects. The major source of cGMP generation in podocytes is natriuretic peptides. The natriuretic peptide clearance receptor (NPRC) binds and degrades natriuretic peptides. As a result, NPRC inhibits natriuretic peptide-induced cGMP generation. To enhance cGMP generation in podocytes, we blocked natriuretic peptide clearance using the specific NPRC ligand ANP(4-23). We then studied the effects of NPRC blockade in both cultured podocytes and in a mouse transgenic (TG) model of focal segmental glomerulosclerosis (FSGS) created in our laboratory. In this model, a single dose of the podocyte toxin puromycin aminonucleoside (PAN) causes robust albuminuria in TG mice, but only mild disease in non-TG animals. We found that natriuretic peptides protected cultured podocytes from PAN-induced apoptosis, and that ANP(4-23) enhanced natriuretic peptide-induced cGMP generation in vivo. PAN-induced heavy proteinuria in vehicle-treated TG mice, and this increase in albuminuria was reduced by treatment with ANP(4-23). Treatment with ANP(4-23) also reduced the number of mice with glomerular injury and enhanced urinary cGMP excretion, but these differences were not statistically significant. Systolic BP was similar in vehicle and ANP(4-23)-treated mice. These data suggest that: 1. Pharmacologic blockade of NPRC may be useful for treating glomerular diseases such as FSGS, and 2. Treatment outcomes might be improved by optimizing NPRC blockade to inhibit natriuretic peptide clearance more effectively., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Objectives: The aim of this multisite quality improvement study was to evaluate patients' experiences with the patient-centered pathology (PCP) consultation program and to determine whether PCP enhanced their care experience., Methods: Patients were invited to attend PCP consultations to review their pathology report and slides and have their questions answered by the pathologist privately, with the option to attend the appointment with family members or friends for support. A patient experience questionnaire (PEQ) was administered to patients, who participated voluntarily in the PCP, and survey data were collected and stored in REDCap. Statistical analysis was performed using SAS 9.4 (SAS Institute)., Results: Sixty-seven patients (95.5% female) aged 18 to 84 years across 4 institutions completed the PEQ. Overall, 58% and 15.8% of patients had breast and brain tumors, respectively, and 59.7% of tumors were newly diagnosed. Most patients thought it was important for them to learn as much as they could about their health condition. However, the majority of patients reported some degree of difficulty learning about their health condition based on written information, despite 97% having completed high school and/or further education. The majority of patients rated their pathologist as "excellent" across communication metrics. Ultimately, 100% of respondents were satisfied, found their visits to be useful, and would recommend the PCP to other patients., Conclusions: Patients found that personalized clinical encounters with pathologists improved their understanding of their health condition and their satisfaction with their care experience. Patients thought pathologists communicated respectfully, effectively, and empathetically., (© American Society for Clinical Pathology, 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A number of neoplasms of the central nervous system can demonstrate diffuse eosinophilic globules, known to be secretory products of the corresponding cell type, but they have not been a salient feature in descriptions of classic ependymoma. Here, we present a case of a posterior fossa ependymoma demonstrating glassy PAS-positive, diastase-resistant, eosinophilic globules with light microscopic and ultrastructural features resembling Reissner fiber, the secretory product of the subcommissural organ. While there has been a single published description of an ependymoma with intra- and extracellular granulofibrillary material suggested to be evidence of secretory differentiation, ours is the first case to demonstrate diffuse eosinophilic globules in an ependymoma. The extent of globules allowed full study by electron microscopy to provide new insight into the secretory material and the surrounding structures. Our findings suggest that neoplastic ependymal cells can recapitulate the secretory capacity of the subcommissural organ.

IRGM and its mouse orthologue Irgm1 are dynamin-like proteins that regulate vesicular remodeling, intracellular microbial killing, and pathogen immunity. IRGM dysfunction is linked to inflammatory bowel disease (IBD), and while it is thought that defective intracellular killing of microbes underscores IBD susceptibility, studies have yet to address how IRGM/Irgm1 regulates immunity to microbes relevant to intestinal inflammation. Here we find that loss of Irgm1 confers marked susceptibility to Citrobacter rodentium, a noninvasive intestinal pathogen that models inflammatory responses to intestinal bacteria. Irgm1-deficient mice fail to control C. rodentium outgrowth in the intestine, leading to systemic pathogen spread and host mortality. Surprisingly, susceptibility due to loss of Irgm1 function was not linked to defective intracellular killing of C. rodentium or exaggerated inflammation, but was instead linked to failure to remodel specific colon lamina propria (C-LP) myeloid cells that expand in response to C. rodentium infection and are essential for C. rodentium immunity. Defective immune remodeling was most striking in C-LP monocytes, which were successfully recruited to the infected C-LP, but subsequently underwent apoptosis. Apoptotic susceptibility was induced by C. rodentium infection and was specific to this setting of pathogen infection, and was not apparent in other settings of intestinal inflammation. These studies reveal a novel role for Irgm1 in host defense and suggest that deficiencies in survival and remodeling of C-LP myeloid cells that control inflammatory intestinal bacteria may underpin IBD pathogenesis linked to IRGM dysfunction., Competing Interests: I have read the journal's policy and have the following competing interests: B.A.V. is the Children with Intestinal and Liver Disorders (C.H.I.L.D.) Foundation Chair in Pediatric Gastroenterology.

We previously developed integrase-defective lentiviral vectors (IDLVs) as an antigen delivery system for inducing strong and prolonged immunity in animal models. Here, we examined the association between persistence of antigen expression and durability of immune response. Following a single intramuscular (i.m.) or subcutaneous (s.c.) injection of IDLV delivering GFP in mice, we evaluated antigen expression and inflammation at the site of injection and persistence of antigen-specific T cells at early and late time points. Durable antigen expression was detected up to 90 days only after i.m. immunization. Mononuclear inflammation was evident soon after IDLV injection in both i.m. and s.c. immunized mice, but remained detectable up to 30 days postinjection only in i.m. immunized mice. Similarly, GFP-specific T cells were more persistent in the i.m. immunized mice. Interestingly, GFP + muscle fibers were co-expressing major histocompatibility complex (MHC) class I, suggesting that muscle cells are competent for presenting antigens to T cells in vivo . In in vitro experiments, we demonstrated that although both primary myoblasts and myocytes present the antigen to GFP-specific T cells through MHC class I, myoblasts are more resistant to Fas-dependent cytotoxic T lymphocyte (CTL) killing activity. Overall, these data indicate that muscle cells may serve as an antigen reservoir that contributes to the long-term immunity induced by IDLV vaccination., (© 2020 The Author(s).)

Gain-of-function mutations in TRPC6 cause familial focal segmental glomerulosclerosis, and TRPC6 is upregulated in glomerular diseases including diabetic kidney disease. We studied the effect of systemic TRPC6 knockout in the Akita model of type 1 diabetes. Knockout of TRPC6 inhibited albuminuria in Akita mice at 12 and 16 weeks of age, but this difference disappeared by 20 weeks. Knockout of TRPC6 also reduced tubular injury in Akita mice; however, mesangial expansion was significantly increased. Hyperglycemia and blood pressure were similar between TRPC6 knockout and wild-type Akita mice, but knockout mice were more insulin resistant. In cultured podocytes, knockout of TRPC6 inhibited expression of the calcium/calcineurin responsive gene insulin receptor substrate 2 and decreased insulin responsiveness. Insulin resistance is reported to promote diabetic kidney disease independent of blood glucose levels. While the mechanisms are not fully understood, insulin activates both Akt2 and ERK, which inhibits apoptosis signal regulated kinase 1 (ASK1)-p38-induced apoptosis. In cultured podocytes, hyperglycemia stimulated p38 signaling and induced apoptosis, which was reduced by insulin and ASK1 inhibition and enhanced by Akt or ERK inhibition. Glomerular p38 signaling was increased in TRPC6 knockout Akita mice and was associated with enhanced expression of the p38 gene target cyclooxygenase 2. These data suggest that knockout of TRPC6 in Akita mice promotes insulin resistance and exacerbates glomerular disease independent of hyperglycemia., (Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Objective: To present a rare case of multiple pituitary adenomas with a functional follicle-stimulating hormone component leading to ovarian hyperstimulation syndrome., Methods: We present the clinical, laboratory, imaging, and pathologic findings along with a review of the literature., Results: A 28-year-old female presented with 5 months of amenorrhea and abdominal pain. Physical exam was unremarkable. Labs revealed elevated prolactin (94 ng/mL), elevated estradiol (608 pg/mL), inappropriately normal follicle-stimulating hormone (10.2 mIU/mL), and suppressed luteinizing hormone (0.36 mIU/mL). Transvaginal ultrasound showed numerous large ovarian cysts bilaterally. Brain magnetic resonance imaging showed a 1.2-cm sellar mass. Various medical therapies were not tolerated due to side effects and the patient underwent gross total resection of the sellar mass with marked improvement in her symptoms and blood hormone levels, resumption of menstruation, and shrinkage of the ovarian cysts. Histologic examination revealed 3 separate staining patterns consistent with multiple pituitary adenomas., Conclusion: Functioning gonadotroph adenomas are rare and often difficult to diagnose, though in premenopausal women they can lead to the distinct clinical presentation of spontaneous ovarian hyperstimulation syndrome. The favored treatment approach is surgical as it has the highest reported success rate. Recurrence is not uncommon and long-term surveillance is recommended. Given limited data on long-term follow-up, the role of available therapies is not well defined, and further research is needed. To our knowledge, this is the first reported case of multiple pituitary adenomas that included a functional gonadotroph component., Competing Interests: DISCLOSURE The authors have no multiplicity of interest to disclose., (Copyright © 2019 AACE.)

Prior to their provisional WHO classification as a distinct entity in 2016, diffuse leptomeningeal glioneuronal tumors (DLGNT) were often regarded as diffuse leptomeningeal presentations of oligodendrogliomas or extraventricular neurocytomas. Their classification as a distinct entity partly relies on their pattern of growth, but DLGNTs without radiological leptomeningeal involvement have been described. In a patient with a DLGNT of the spinal cord without evidence of leptomeningeal involvement, we review in depth the clinical course and the histologic and molecular features of the neoplasm, in the context of other reported cases without diffuse leptomeningeal involvement. Our findings highlight the advantages of molecular analysis in making accurate diagnoses on small spinal tissue samples and underline the need for more long-term clinical follow-up of these rare neoplasms to inform treatment decisions.

Expression of a constitutively active Rho A (V14Rho) in podocytes in vivo induces albuminuria and foot process (FP) effacement. These effects may be mediated by the Rho A effector Rho kinase (ROK); but inhibition of ROK with Y27632 failed to attenuate albuminuria or FP effacement in V14Rho mice. ROK activates LIM kinases (LIMKs), which phosphorylate and inhibit the actin depolymerizing factor cofilin 1 (CFL1). Sustained phosphorylation of CFL1 is implicated in human nephrotic diseases, but Y27632 did not inhibit phosphorylation of CFL1 in vivo, despite effective ROK inhibition. CFL1 is also phosphorylated by testis-specific kinase 1 (TESK1) on the same serine residue. TESK1 was expressed in podocytes, and, similar to the in vivo situation, Y27632 had little effect on phospho-CFL1 (pCFL1) levels in cultured podocytes. In contrast, Y27632 reduced pCFL1 levels in TESK1 knockout (KO) cells. ROK inhibition enhanced podocyte motility but, the motility promoting effect of Y27632 was absent in TESK1 KO podocytes. Thus, TESK1 regulates podocyte cytoskeletal dynamics in glomerular podocytes and may play an important role in regulating glomerular filtration barrier integrity in glomerular disease processes.

GLE1 encodes a protein important for mRNA export and appears to play roles in translation initiation and termination as well. Pathogenic variants in GLE1 mutations have been associated with lethal contracture syndrome and lethal arthrogryposis with anterior horn cell disease; phenotypes reported in individuals include fetal akinesia and a severe form of motor neuron disease, typically presenting with prenatal symptoms and perinatal lethality. In this article, we identified biallelic missense mutations in GLE1 by trio whole-exome sequencing in an individual affected with congenital motor weakness and contractures as well as feeding and respiratory difficulties. Muscle biopsy was consistent with anterior horn cell disease and supported the pathogenicity of the sequence variants. Importantly, this individual survived past the perinatal period with respiratory support and currently demonstrates age-appropriate cognition and slow but steady motor developmental progress. We propose that pathogenic variants in GLE1 can be associated with a nonperinatal lethal motor phenotype, and affected individuals can demonstrate motor skill progression, unlike prototypical anterior horn cell diseases such as spinal muscular atrophy., (© 2017 Tan et al.; Published by Cold Spring Harbor Laboratory Press.)

PRKAG2 encodes the γ2 subunit of AMP-activated protein kinase (AMPK), which is an important regulator of cardiac metabolism. Mutations in PRKAG2 cause a cardiac syndrome comprising ventricular hypertrophy, pre-excitation, and progressive conduction-system disease, which is typically not diagnosed until adolescence or young adulthood. However, significant variability exists in the presentation and outcomes of patients with PRKAG2 mutations, with presentation in infancy being underrecognized. The diagnosis of PRKAG2 can be challenging in infants, and we describe our experience with three patients who were initially suspected to have Pompe disease yet ultimately diagnosed with mutations in PRKAG2. A disease-causing PRKAG2 mutation was identified in each case, with a novel missense mutation described in one patient. We highlight the potential for patients with PRKAG2 mutations to mimic Pompe disease in infancy and the need for confirmatory testing when diagnosing Pompe disease.

Enhanced expression of cyclooxygenase 2 (COX2) in podocytes contributes to glomerular injury in diabetic kidney disease, but some basal level of podocyte COX2 expression might be required to promote podocyte attachment and/or survival. To investigate the role of podocyte COX2 expression in diabetic kidney disease, we deleted COX2 specifically in podocytes in a mouse model of Type 1 diabetes mellitus (Akita mice). Podocyte-specific knockout (KO) of COX2 did not affect renal morphology or albuminuria in nondiabetic mice. Albuminuria was significantly increased in wild-type (WT) and KO Akita mice compared with nondiabetic controls, and the increase in albuminuria was significantly greater in KO Akita mice compared with WT Akita mice at both 16 and 20 wk of age. At the 20-wk time point, mesangial expansion was also increased in WT and KO Akita mice compared with nondiabetic animals, and these histologic abnormalities were not improved by KO of COX2. Tubular injury was seen only in diabetic mice, but there were no significant differences between groups. Thus, KO of COX2 enhanced albuminuria and did not improve the histopathologic features of diabetic kidney disease. These data suggest that 1 ) KO of COX2 in podocytes does not ameliorate diabetic kidney disease in Akita mice, and 2 ) some basal level of podocyte COX2 expression in podocytes is necessary to attenuate the adverse effects of diabetes on glomerular filtration barrier function.

Many inborn errors of metabolism can cause cardiomyopathy. Cardiomyopathy associated with glycogen storage includes PRKAG2-associated glycogen storage disease (GSD), Danon disease, infantile-onset Pompe disease (GSD II), GSD III, GSD IV, and phosphofructokinase deficiency (Tarui disease or GSD VII).We present a 35-year-old female who presented with cardiomyopathy after a pregnancy complicated by primary hyperparathyroidism. She had enjoyed excellent health until her first pregnancy at age 33. One week postpartum, she developed dyspnea and an echocardiogram revealed left ventricular ejection fraction (LVEF) of 35%. A cardiac MRI was consistent with nonischemic cardiomyopathy with an infiltrative process. Endomyocardial biopsy showed striking sarcoplasmic vacuolization, excess glycogen by PAS staining, and frequent membrane-bound glycogen by electron microscopy, consistent with lysosomal GSD. Acid alpha-glucosidase (GAA) activity in skin fibroblasts was in the affected range for Pompe disease. Sequencing of the GAA gene revealed a paternally inherited pathogenic c.525delT (p.Glu176Argfs*45) and a de novo c.309C>G (p.Cys103Trp) with unknown pathogenicity. Testing of the familial mutations in her daughter indicated that the variants in the proband were in trans. 26-gene cardiomyopathy sequencing panel had normal results thereby excluding GSD III, Danon disease, Fabry disease, and PRKAG2-associated cardiomyopathy. Therefore, results strongly suggest a diagnosis of Pompe disease.Pompe disease has a broad disease spectrum, including infantile-onset (IOPD) and late-onset (LOPD) forms. LOPD typically presents with proximal muscle weakness and respiratory insufficiency in childhood or late adulthood. Our case may represent a very unusual presentation of adult LOPD with isolated cardiomyopathy without skeletal muscle involvement or respiratory failure.

Multivariate biomarkers are needed for detecting Alzheimer's disease (AD), understanding its etiology, and quantifying the effect of therapies. Mouse models provide opportunities to study characteristics of AD in well-controlled environments that can help facilitate development of early interventions. The CVN-AD mouse model replicates multiple AD hallmark pathologies, and we identified multivariate biomarkers characterizing a brain circuit disruption predictive of cognitive decline. In vivo and ex vivo magnetic resonance imaging (MRI) revealed that CVN-AD mice replicate the hippocampal atrophy (6%), characteristic of humans with AD, and also present changes in subcortical areas. The largest effect was in the fornix (23% smaller), which connects the septum, hippocampus, and hypothalamus. In characterizing the fornix with diffusion tensor imaging, fractional anisotropy was most sensitive (20% reduction), followed by radial (15%) and axial diffusivity (2%), in detecting pathological changes. These findings were strengthened by optical microscopy and ultrastructural analyses. Ultrastructual analysis provided estimates of axonal density, diameters, and myelination-through the g-ratio, defined as the ratio between the axonal diameter, and the diameter of the axon plus the myelin sheath. The fornix had reduced axonal density (47% fewer), axonal degeneration (13% larger axons), and abnormal myelination (1.5% smaller g-ratios). CD68 staining showed that white matter pathology could be secondary to neuronal degeneration, or due to direct microglial attack. In conclusion, these findings strengthen the hypothesis that the fornix plays a role in AD, and can be used as a disease biomarker and as a target for therapy., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Inappropriate activation of the renin angiotensin system (RAS) is a key contributor to the pathogenesis of essential hypertension. During RAS activation, infiltration of immune cells into the kidney exacerbates hypertension and renal injury. However, the mechanisms underpinning the accumulation of mononuclear cells in the kidney after RAS stimulation remain unclear. C-C motif chemokine 5 (CCL5) drives recruitment of macrophages and T lymphocytes into injured tissues, and we have found that RAS activation induces CCL5 expression in the kidney during the pathogenesis of hypertension and renal fibrosis. We therefore evaluated the contribution of CCL5 to renal damage and fibrosis in hypertensive and normotensive models of RAS stimulation. Surprisingly, during angiotensin II-induced hypertension, CCL5-deficient (knockout, KO) mice exhibited markedly augmented kidney damage, macrophage infiltration, and expression of proinflammatory macrophage cytokines compared with wild-type controls. When subjected to the normotensive unilateral ureteral obstruction model of endogenous RAS activation, CCL5 KO mice similarly developed more severe renal fibrosis and greater accumulation of macrophages in the kidney, congruent with enhanced renal expression of the macrophage chemokine CCL2. In turn, pharmacologic inhibition of CCL2 abrogated the differences between CCL5 KO and wild-type mice in kidney fibrosis and macrophage infiltration after unilateral ureteral obstruction. These data indicate that CCL5 paradoxically limits macrophage accumulation in the injured kidney during RAS activation by constraining the proinflammatory actions of CCL2., (Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)

The cascade that culminates in macrometastases is thought to be mediated by phenotypic plasticity, including epithelial-mesenchymal and mesenchymal-epithelial transitions (EMT and MET). Although there is substantial support for the role of EMT in driving cancer cell invasion and dissemination, much less is known about the importance of MET in the later steps of metastatic colonization. We created novel reporters, which integrate transcriptional and post-transcriptional regulation, to test whether MET is required for metastasis in multiple in vivo cancer models. In a model of carcinosarcoma, metastasis occurred via an MET-dependent pathway; however, in two prostate carcinoma models, metastatic colonization was MET independent. Our results provide evidence for both MET-dependent and MET-independent metastatic pathways., Competing Interests: The authors have no conflicts to disclose.

Rhabdomyomatous mesenchymal hamartoma (RMH) is a rare congenital malformation involving the dermis and subcutaneous tissue, of which there were 62 reported cases through 2014. We report RMH in two neonates presenting as a sacral skin tag. In both cases, magnetic resonance imaging (MRI) of the spine showed evidence of spinal dysraphism, including a lipomyelomeningocele and a tethered cord. Surgical repair of the defects was performed. Histopathologic examination of the skin tags showed a haphazard arrangement of mature skeletal muscle fibers and adnexal elements, consistent with RMH. The second patient also had a hemangioma on the sacrum and was diagnosed with LUMBAR (lower body hemangioma and other cutaneous defects, urogenital anomalies/ulceration, myelopathy, bony deformities, anorectal/arterial anomalies, and renal anomalies) syndrome, an association between cutaneous infantile hemangiomas of the lower body and regional congenital anomalies. The apparent association of paraspinal RMH with spinal dysraphism suggests that aberrant migration of mesodermally derived tissues (including skeletal muscle fibers) during neural tube development may be responsible for the pathologic findings in the skin. Additional study of patients with spinal dysraphism and congenital cutaneous lesions may further support this hypothesis., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Familial forms of focal segmental glomerulosclerosis (FSGS) have been linked to gain-of-function mutations in the gene encoding the transient receptor potential channel C6 (TRPC6). GPCRs coupled to Gq signaling activate TRPC6, suggesting that Gq-dependent TRPC6 activation underlies glomerular diseases. Here, we developed a murine model in which a constitutively active Gq α subunit (Gq(Q209L), referred to herein as GqQ>L) is specifically expressed in podocytes and examined the effects of this mutation in response to puromycin aminonucleoside (PAN) nephrosis. We found that compared with control animals, animals expressing GqQ>L exhibited robust albuminuria, structural features of FSGS, and reduced numbers of glomerular podocytes. Gq activation stimulated calcineurin (CN) activity, resulting in CN-dependent upregulation of TRPC6 in murine kidneys. Deletion of TRPC6 in GqQ>L-expressing mice prevented FSGS development and inhibited both tubular damage and podocyte loss induced by PAN nephrosis. Similarly, administration of the CN inhibitor FK506 reduced proteinuria and tubular injury but had more modest effects on glomerular pathology and podocyte numbers in animals with constitutive Gq activation. Moreover, these Gq-dependent effects on podocyte injury were generalizable to diabetic kidney disease, as expression of GqQ>L promoted albuminuria, mesangial expansion, and increased glomerular basement membrane width in diabetic mice. Together, these results suggest that targeting Gq/TRPC6 signaling may have therapeutic benefits for the treatment of glomerular diseases.

Cranial irradiation is a standard therapy for primary and metastatic brain tumors. A major drawback of radiotherapy (RT), however, is long-term cognitive loss that affects quality of life. Radiation-induced oxidative stress in normal brain tissue is thought to contribute to cognitive decline. We evaluated the effectiveness of a novel mimic of superoxide dismutase enzyme (SOD), MnTnBuOE-2-PyP(5+)(Mn(III) meso-tetrakis(N-n-butoxyethylpyridinium-2-yl)porphyrin), to provide long-term neuroprotection following 8 Gy of whole brain irradiation. Long-term RT damage can only be assessed by brain imaging and neurocognitive studies. C57BL/6J mice were treated with MnTnBuOE-2-PyP(5+) before and after RT and evaluated three months later. At this time point, drug concentration in the brain was 25 nmol/L. Mice treated with MnTnBuOE-2-PyP(5+)/RT exhibited MRI evidence for myelin preservation in the corpus callosum compared with saline/RT treatment. Corpus callosum histology demonstrated a significant loss of axons in the saline/RT group that was rescued in the MnTnBuOE-2-PyP(5+)/RT group. In addition, the saline/RT groups exhibited deficits in motor proficiency as assessed by the rotorod test and running wheel tests. These deficits were ameliorated in groups treated with MnTnBuOE-2-PyP(5+)/RT. Our data demonstrate that MnTnBuOE-2-PyP(5+) is neuroprotective for oxidative stress damage caused by radiation exposure. In addition, glioblastoma cells were not protected by MnTnBuOE-2-PyP(5+) combination with radiation in vitro. Likewise, the combination of MnTnBuOE-2-PyP(5+) with radiation inhibited tumor growth more than RT alone in flank tumors. In summary, MnTnBuOE-2-PyP(5+) has dual activity as a neuroprotector and a tumor radiosensitizer. Thus, it is an attractive candidate for adjuvant therapy with RT in future studies with patients with brain cancer., (©2014 American Association for Cancer Research.)

In a wide array of kidney diseases, type 1 angiotensin (AT1) receptors are present on the immune cells that infiltrate the renal interstitium. Here, we examined the actions of AT1 receptors on macrophages in progressive renal fibrosis and found that macrophage-specific AT1 receptor deficiency exacerbates kidney fibrosis induced by unilateral ureteral obstruction (UUO). Macrophages isolated from obstructed kidneys of mice lacking AT1 receptors solely on macrophages had heightened expression of proinflammatory M1 cytokines, including IL-1. Evaluation of isolated AT1 receptor-deficient macrophages confirmed the propensity of these cells to produce exaggerated levels of M1 cytokines, which led to more severe renal epithelial cell damage via IL-1 receptor activation in coculture compared with WT macrophages. A murine kidney crosstransplantation concomitant with UUO model revealed that augmentation of renal fibrosis instigated by AT1 receptor-deficient macrophages is mediated by IL-1 receptor stimulation in the kidney. This study indicates that a key role of AT1 receptors on macrophages is to protect the kidney from fibrosis by limiting activation of IL-1 receptors in the kidney.

Effective dosages for enzyme replacement therapy (ERT) in Pompe disease are much higher than for other lysosomal storage disorders, which has been attributed to low cation-independent mannose-6-phosphate receptor (CI-MPR) in skeletal muscle. We have previously demonstrated the benefit of increased CI-MPR-mediated uptake of recombinant human acid-α-glucosidase during ERT in mice with Pompe disease following addition of albuterol therapy. Currently we have completed a pilot study of albuterol in patients with late-onset Pompe disease already on ERT for >2 yr, who were not improving further. The 6-min walk test (6MWT) distance increased in all 7 subjects at wk 6 (30±13 m; P=0.002), wk 12 (34±14 m; P=0.004), and wk 24 (42±37 m; P=0.02), in comparison with baseline. Grip strength was improved significantly for both hands at wk 12. Furthermore, individual subjects reported benefits; e.g., a female patient could stand up from sitting on the floor much more easily (time for supine to standing position decreased from 30 to 11 s), and a male patient could readily swing his legs out of his van seat (hip abduction increased from 1 to 2+ on manual muscle testing). Finally, analysis of the quadriceps biopsies suggested increased CI-MPR at wk 12 (P=0.08), compared with baseline. With the exception of 1 patient who succumbed to respiratory complications of Pompe disease in the first week, only mild adverse events have been reported, including tremor, transient difficulty falling asleep, and mild urinary retention (requiring early morning voiding). Therefore, this pilot study revealed initial safety and efficacy in an open label study of adjunctive albuterol therapy in patients with late-onset Pompe disease who had been stable on ERT with no improvements noted over the previous several years.

To determine if augmenting podocyte injury promotes the development of advanced diabetic nephropathy (DN), we created mice that expressed the enzyme cytosine deaminase (CD) specifically in podocytes of diabetic Akita mice (Akita-CD mice). In these mice, treatment with the prodrug 5-flucytosine (5-FC) causes podocyte injury as a result of conversion to the toxic metabolite 5-fluorouracil (5-FU). We found that treatment of 4-5 week old Akita mice with 5-FC for 5 days caused robust albuminuria at 16 and 20 weeks of age compared to 5-FC treated Akita controls, which do not express CD (Akita CTLs). By 20 weeks of age, there was a significant increase in mesangial expansion in Akita-CD mice compared to Akita CTLs, which was associated with a variable increase in glomerular basement membrane (GBM) width and interstitial fibrosis. At 20 weeks of age, podocyte number was similarly reduced in both groups of Akita mice, and was inversely correlated with the albuminuria and mesangial expansion. Thus, enhancing podocyte injury early in the disease process promotes the development of prominent mesangial expansion, interstitial fibrosis, increased GBM thickness and robust albuminuria. These data suggest that podocytes play a key role in the development of advanced features of diabetic kidney disease., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Blood vessels are often overlooked in analyses of skeletal muscle biopsies. However, there are many vascular features in skeletal muscle biopsies that, when interpreted in the context of other histologic patterns and clinical history, provide useful information that allows muscle pathologists to narrow their differential diagnoses and provide more accurate guidance to treating physicians. Here, we provide a review of normal skeletal muscle vasculature with details of the ultrastructure of vessel walls. We discuss the vascular effects of factors common to many patients undergoing muscle biopsy, for example, diabetes mellitus, hypertension, and aging. We then discuss vascular findings relevant to diagnostic muscle biopsy evaluation, with current theories of pathogenesis and detailed descriptions of the important features.

Background: Pompe disease is an autosomal recessive metabolic neuromuscular disorder caused by a deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA). It has long been believed that the underlying pathology leading to tissue damage is caused by the enlargement and rupture of glycogen-filled lysosomes. Recent studies have also implicated autophagy, an intracellular lysosome-dependent degradation system, in the disease pathogenesis. In this study, we characterize the long-term impact of enzyme replacement therapy (ERT) with recombinant human GAA (rhGAA) on lysosomal glycogen accumulation and autophagy in some of the oldest survivors with classic infantile Pompe disease (IPD)., Methods: Muscle biopsies from 8 [4 female, 4 male; 6 cross-reactive immunologic material (CRIM)-positive, 2 CRIM-negative] patients with a confirmed diagnosis of classic IPD were examined using standard histopathological approaches. In addition, muscle biopsies were evaluated by immunostaining for lysosomal marker (lysosomal-associated membrane protein-2; LAMP2), autophagosomal marker (microtubule-associated protein 1 light chain 3; LC3), and acid and alkaline ATPases. All patients received rhGAA by infusion at cumulative biweekly doses of 20-40 mg/kg., Results: Median age at diagnosis of classic IPD was 3.4 months (range: 0 to 6.5 months; n = 8). At the time of muscle biopsy, the patients' ages ranged from 1 to 103 months and ERT duration ranged from 0 (i.e., baseline, pre-ERT) to 96 months. The response to therapy varied considerably among the patients: some patients demonstrated motor gains while others experienced deterioration of motor function, either with or without a period of initial clinical benefit. Skeletal muscle pathology included fiber destruction, lysosomal vacuolation, and autophagic abnormalities (i.e., buildup), particularly in fibers with minimal lysosomal enlargement. Overall, the pathology reflected clinical status., Conclusions: This is the first study to investigate the impact of rhGAA ERT on lysosomal glycogen accumulation and autophagic buildup in patients with classic IPD beyond 18 months of treatment. Our findings indicate that ERT does not fully halt or reverse the underlying skeletal muscle pathology in IPD. The best outcomes were observed in the two patients who began therapy early, namely at 0.5 and 1.1 months of age.

Medulloblastoma (MB) is the most common malignant brain tumor in children. Patients whose tumors exhibit overexpression or amplification of the MYC oncogene (c-MYC) usually have an extremely poor prognosis, but there are no animal models of this subtype of the disease. Here, we show that cerebellar stem cells expressing Myc and mutant Trp53 (p53) generate aggressive tumors following orthotopic transplantation. These tumors consist of large, pleiomorphic cells and resemble human MYC-driven MB at a molecular level. Notably, antagonists of PI3K/mTOR signaling, but not Hedgehog signaling, inhibit growth of tumor cells. These findings suggest that cerebellar stem cells can give rise to MYC-driven MB and identify a novel model that can be used to test therapies for this devastating disease., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Introduction: Malignant glioma remains a significant therapeutic challenge, and immunotherapeutics might be a beneficial approach for these patients. A monoclonal antibody (MAb) specific for multiple molecular targets could expand the treatable patient population and the fraction of tumor cells targeted, with potentially increased efficacy. This motivated the generation of MAb D2C7, which recognizes both wild-type epidermal growth factor receptor (EGFRwt) and a tumor-specific mutant, EGFRvIII., Methods: D2C7 binding affinity was determined by surface plasmon resonance and its specificity characterized through comparison to EGFRwt-specific EGFR.1 and EGFRvIII-specific L8A4 MAbs by flow cytometry and immunohistochemical analysis. The three MAbs were labeled with (125)I or (131)I using Iodogen, and paired-label internalization assays and biodistribution experiments in athymic mice with human tumor xenografts were performed., Results: The affinity of D2C7 for EGFRwt and EGFRvIII was 5.2×10(9) M(-1) and 3.6×10(9) M(-1), and cell-surface reactivity with both receptors was documented by flow cytometry. Immunohistochemical analyses revealed D2C7 reactivity with malignant glioma tissue from 90 of 101 patients. Internalization assays performed on EGFRwt-expressing WTT cells and EGFRvIII-expressing NR6M cells indicated a threefold lower degradation of (125)I-labeled D2C7 compared with (131)I-labeled EGFR.1. Uptake of (125)I-labeled D2C7 in NR6M xenografts (52.45±13.97 %ID g(-1) on Day 3) was more than twice that of (131)I-labeled L8A4; a threefold to fivefold tumor delivery advantage was seen when compared to (131)I-labeled EGFR.1 in mice with WTT xenografts., Conclusions: These results suggest that D2C7 warrants further evaluation for the development of MAb-based therapeutics against cancers expressing EGFRwt and EGFRvIII., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Epidermal growth factor receptor (EGFR) is frequently overexpressed in hepatocellular carcinoma, but its relationship with EGFR gene copy number has not been studied. This study examined EGFR expression and gene copy number in hepatocellular carcinoma and evaluated their relationship to clinicopathologic features in 76 tumors. Moderate to strong expression of EGFR was observed by immunohistochemical analysis in 50 (66%) of 76 hepatocellular carcinomas. Fluorescence in situ hybridization (FISH) showed extra EGFR gene copies in 17 (45%) of 38 tumors. This was accompanied by gains of chromosome 7, indicating that this was the result of balanced polysomy rather than gene amplification. There was no correlation between EGFR expression by immunohistochemical analysis and gene copy number by FISH. EGFR expression showed borderline association with cirrhosis but not with other clinicopathologic parameters examined. EGFR overexpression is present in a majority of hepatocellular carcinomas, suggesting a role for EGFR antagonists in therapy. The increased expression does not correlate with an increase in the EGFR gene copy number.

Immunohistochemistry is widely used to assess epidermal growth factor receptor (EGFR) expression on colorectal carcinomas to select patients for treatment with cetuximab, an anti-EGFR antibody. The data comparing different commercial EGFR antibodies is limited, and no cost comparisons have been made. We analyzed 65 advanced colorectal cancers from 36 patients using the EGFR pharmDx kit (DakoCytomation) and Clone 31G7 (Zymed Laboratories, Inc). EGFR expression was seen in 35 (53%) tumors (21 primary, 14 metastatic) with the Dako pharmDx kit. The Zymed antibody showed positive results in 41 (63%) tumors (25 primary, 16 metastatic). The cost per test was $40.00 with the pharmDx kit and $3.52 with the Zymed antibody. The Zymed antibody detects 10% more cases of colorectal cancer as EGFR positive, and is 10 times cheaper than the Dako pharmDx kit. There is little justification for the use of expensive kits for testing EGFR expression, when other available antibodies without the kit can give comparable or superior results.

Anxiety disorders are among the most prevalent forms of adult and childhood psychiatric disorders, and they are highly familial. However, the mechanisms of transmission remain unclear. One familial characteristic that may promote the development of anxiety is the construct of parental control. This paper provides a conceptual overview of the construct of control in the parenting and anxiety literatures, reviews existing literature on control in anxious families, and reviews current conceptual models of and developmental approaches to anxiety. Based on the current empirical literature, an elaborated model that takes child developmental level into consideration is proposed in order to provide a better understanding of the role of parental control in the development of anxiety.

Increased expression of epidermal growth factor receptor (EGFR), a transmembrane tyrosine kinase, is associated with tumor progression in many carcinomas. Epidermal growth factor receptor inhibitors have shown promise in treating some of these tumors. Fibrolamellar hepatocellular carcinoma (FL-HCC) is an aggressive neoplasm that occurs in young patients with no history of cirrhosis. This study examines the expression and gene copy number of EGFR in FL-HCC. Formalin-fixed, paraffin-embedded FL-HCC (n = 13) sections were stained with a monoclonal antibody against EGFR. Fluorescence in situ hybridization analysis was performed using probes against EGFR gene and centromeric region of chromosome 7 (CEP 7). Epidermal growth factor receptor and CEP 7 signals were counted in 50 tumor nuclei per case as well as 300 normal hepatocyte nuclei. The EGFR to CEP 7 signal ratio was calculated for each case. Most (92%, 12/13) of FL-HCC showed strong and diffuse staining with anti-EGFR antibody. Fluorescence in situ hybridization was informative in 11 cases, 10 of which showed extra EGFR gene copy numbers (mean, 3.69; range, 3.13-5.0). Epidermal growth factor receptor was overexpressed in all these cases. The mean number of EGFR signals per cell in FL-HCC was double that of normal hepatocytes (3.69 versus 1.80); the mean EGFR/CEP 7 ratio in tumor cells was 1.05. In conclusion, EGFR is strongly overexpressed on the cell membrane in nearly all cases of FL-HCC. Similar gains of chromosome 7 are observed, indicating that the extra EGFR gene copies are due to polysomy rather than gene amplification. The strong expression of EGFR in FL-HCC tumors suggests that they may respond to treatment with EGFR antagonists.

Research has focused on defining which types of family interactions promote development of anxiety. Control has emerged as an important construct in anxious families. Central to conceptualizing the relationship between family functioning, control beliefs, and anxiety is establishing a sequential relationship among these variable, which may entail mediating or moderating relationships, or relationships that change over the course of development. The current study investigated whether control acts as a moderator or a mediator between perceived family environment and anxiety in your adults. An undergraduate sample (N=364) completed the family assessment device (FAD), anxiety control questionnaire (ACQ), Beck anxiety inventory (BAI), and a demographic questionnaire. Structural equation modeling (SEM) was used to test both moderating and mediating models. No moderating effects were found. Sense of control mediated the relation between aspects of family functioning and anxiety. Theoretical implications and suggestions for future research are discussed.

T lymphocytes circulate in a quiescent state until they encounter cognate antigen bound to the surface of an antigen-presenting cell. The molecular pathways that regulate T cell quiescence remain largely unknown. Here we show that forced expression of the lung Krüppel-like transcription factor (LKLF) in Jurkat T cells is sufficient to program a quiescent phenotype characterized by decreased proliferation, reduced cell size and protein synthesis and decreased surface expression of activation markers. Conversely, LKLF-deficient peripheral T cells produced by gene targeting showed increased proliferation, increased cell size and enhanced expression of surface activation markers in vivo. LKLF appeared to function, at least in part, by decreasing expression of the proto-oncogene encoding c-Myc. Forced expression of LKLF was associated with markedly decreased c-Myc expression. In addition, many effects of LKLF expression were mimicked by expression of the dominant-negative MadMyc protein and rescued by overexpression of c-Myc. Thus, LKLF is both necessary and sufficient to program quiescence in T cells and functions, in part, by negatively regulating a c-Myc--dependent pathway.