LMOD2-related dilated cardiomyopathy presenting in late infancy

Leiomodin-2 (LMOD2) is an important regulator of the thin filament length, known to promote elongation of actin through polymerization at pointed ends. Mice with Lmod2 deficiency die around 3 weeks of age due to severe dilated cardiomyopathy (DCM), resulting from decreased heart contractility due to shorter thin filaments. To date, there have been three infants from two families reported with biallelic variants in LMOD2, presenting with perinatal onset DCM. Here, we describe a third family with a child harboring a previously described homozygous frameshift variant, c.1243_1244delCT (p.L415Vfs*108) with DCM, presenting later in infancy at 9 months of age. Family history was relevant for a sibling who died suddenly at 1 year of age after being diagnosed with cardiomegaly. LMOD2-related cardiomyopathy is a rare form of inherited cardiomyopathy resulting from thin filament length dysregulation and should be considered in genetic evaluation of newborns and infants with suspected autosomal recessive inheritance or sporadic early onset cardiomyopathy.

Acute Strokelike Presentation and Long-term Evolution of Diffusion Restriction Pattern in Ethylmalonic Encephalopathy

Ethylmalonic encephalopathy is a rare autosomal recessive mitochondrial disorder caused by pathogenic biallelic variants in the ETHE1 gene. The phenotype of this disease has been attributed to deficiency in the mitochondrial sulfur dioxygenase leading to many downstream effects. Ethylmalonic encephalopathy classically presents with developmental regression, petechiae, acrocyanosis, and chronic diarrhea. The neurologic phenotype includes hypotonia, spastic diplegia, ataxia, and developmental delay. As more patients with this condition are described, the neurologic phenotype continues to expand. Although strokelike episodes or metabolic strokes have been studied in other mitochondrial disorders, they have not been thoroughly reported in this disorder. Herein, we describe 3 patients with ethylmalonic encephalopathy who presented clinically with strokelike episodes and strokelike abnormalities on brain magnetic resonance imaging in the setting of acute illness, and the long-term sequelae with evolution into cystic changes in one of these subjects.

Sudden infant death with dysgenesis of the testes syndrome in a non-Amish infant: A case report

Sudden Infant Death with Dysgenesis of the Testes syndrome (SIDDT) is a very rare condition associated with biallelic pathogenic variants in the TSPYL1 gene first reported in 2004. It is characterized by sudden cardiac or respiratory arrest, disordered testicular development, neurologic dysfunction, and is uniformly fatal before the age of 12 months. There were previously 21 reported cases of SIDDT in the literature, all from nine Old Order Amish families published in a single paper. In this report, we describe a non-Amish, phenotypically female infant with poor feeding and abnormal motor movements noted at birth. Initial testing showed that she had a 46,XY chromosome complement, and chromosomal microarray showed a significant absence of heterozygosity (AOH) totalling roughly 600 Mb across multiple different chromosomes, indicating consanguinity. Further workup with exome sequencing revealed homozygosity for a frameshift variant in TSPYL1 (c.725_726delTG, p.Val242GlufsTer52) consistent with a diagnosis of SIDDT, explaining many of her clinical features. However, she was also noted to have a mild T-cell lymphopenia and developed intractable epilepsy after hospital discharge. These features have not previously been reported in SIDDT and may represent phenotypic expansion. To our knowledge, this patient is the 22nd case of SIDDT to be reported in the literature, and the first to be of non-Amish heritage.

Further studies of the down-regulation by Factor I of the C3b feedback cycle using endotoxin as a soluble activator and red cells as a source of CR1 on sera of different complotype

In this paper we have extended our earlier studies of the action of increasing Factor I concentration on complement activation by using a soluble activator, lipopolysaccharide (LPS) endotoxin, and using human erythrocytes as a source of CR1 - the co-factor needed for the final clip of iC3b to C3dg by Factor I. Using this more physiological system, the results show that we can predict that a quite modest increase in Factor I concentration - 22 µg/ml of extra Factor I - will convert the activity of the highest risk sera to those of the lowest risk. Preliminary experiments have been performed with erythrocytes allotyped for CR1 number. While we have not been able to perform an adequate study of their co-factor activities in our assays, preliminary experiments suggest that when Factor I levels are increased the difference produced by different allotypes of red cells is largely overcome. This suggests that in patients with paroxysmal nocturnal haemoglobinuria (PNH) treated with eculizumab, additional treatment with Factor I may be very useful in reducing the need for blood transfusion. We have also explored the age-related allele frequency for the two polymorphisms of Factor H and the polymorphism of C3. In our population, unlike the 1975 study, we found no age variation in the allele frequency in these polymorphisms. This may, however, reflect that the Cambridge BioResource volunteers do not include many very young or very elderly patients, and in general comprise a population not greatly at risk of death from infectious disease.

Complotype affects the extent of down-regulation by Factor I of the C3b feedback cycle in vitro

Sera from a large panel of normal subjects were typed for three common polymorphisms, one in C3 (R102G) and two in Factor H (V62I and Y402H), that influence predisposition to age-related macular degeneration and to some forms of kidney disease. Three groups of sera were tested; those that were homozygous for the three risk alleles; those that were heterozygous for all three; and those homozygous for the low-risk alleles. These groups vary in their response to the addition of exogenous Factor I when the alternative complement pathway is activated by zymosan. Both the reduction in the maximum amount of iC3b formed and the rate at which the iC3b is converted to C3dg are affected. For both reactions the at-risk complotype requires higher doses of Factor I to produce similar down-regulation. Because iC3b reacting with the complement receptor CR3 is a major mechanism by which complement activation gives rise to inflammation, the breakdown of iC3b to C3dg can be seen to have major significance for reducing complement-induced inflammation. These findings demonstrate for the first time that sera from subjects with different complement alleles behave as predicted in an in-vitro assay of the down-regulation of the alternative complement pathway by increasing the concentration of Factor I. These results support the hypothesis that exogenous Factor I may be a valuable therapeutic aid for down-regulating hyperactivity of the C3b feedback cycle, thereby providing a treatment for age-related macular degeneration and other inflammatory diseases of later life.

Abstract 5470: Blocking wound-induced tumor repopulation between chemotherapy cycles as a novel approach to abrogate chemoresistance

Acquired chemoresistance remains a major clinical issue in the management of advanced solid cancers. Initial response to cytotoxic chemotherapy is common, but certain patients progressively become unresponsive after multiple chemotherapy cycles. While causes of drug resistance are multiple and complex, here we approach this problem from a new angle: we studied whether repopulation of residual surviving cancer cells between chemotherapy cycles contributes to progressive chemoresistance. Currently the identity of repopulating cancer cells following chemotherapy is unknown, and the underlying molecular mechanisms that initiate tumor repopulation remain poorly understood. In the present study we use bladder cancer as a model and report that quiescent cancer stem cells (CSCs) are unexpectedly recruited to proliferate and repopulate residual tumors in response to chemotherapy-induced damage. This phenomenon is similar to how normal resident tissue stem cells mobilize to wound sites for tissue repair. We further investigate whether blockade of this wound-induced CSC repopulation can provide an innovative approach to abrogate chemoresistance.

Previously we showed that cytokeratin 14 (CK14) marks the most primitive bladder cancer cells and abundance of CK14+ cancer cells in patients correlates with poor survival. Here, we followed the standard clinical chemotherapy regimen with gap periods to allow recovery of normal tissues between treatment cycles. While one cycle of gemcitabine and cisplatin effectively reduced tumor growth in vivo, a generalized expansion of CK14+ CSCs occurred in residual tumors during these gap periods between cycles. Further analysis revealed the induction of a “wound-response” gene signature in residual tumors and active recruitment of quiescent CSCs into proliferation in response to chemotherapy-induced damage. We demonstrated that prostaglandin E2 (PGE2) released by neighboring dying cancer cells could induce CSC expansion in a paracrine manner. This undesirable CSC expansion could be abrogated by a PGE2 neutralizing antibody and Celecoxib, an FDA approved COX2 inhibitor that blocks PGE2 signaling. In vivo administration of Celecoxib blocked the induction of “wound-response” gene signature and significantly attenuated progressive development of chemoresistance in xenograft tumors, including primary xenografts derived from a patient who failed chemotherapy.These results revealed a new mechanism by which CSCs contribute to therapeutic resistance via repopulating residual tumors between chemotherapy cycles. Repopulation was initiated by dying cells that induced wound response and recruitment of CSCs to repair chemotherapy-induced damages. Therapeutic intervention with Celecoxib effectively blocked this process and improved chemotherapeutic response in bladder tumors, supporting further validation in other solid cancers.

Citation Format: Antonina V. Kurtova, Jing Xiao, Qianxing Mo, Senthil Pazhanisamy, Ross Krasnow, Seth P. Lerner, Fengju Chen, Terrence Roh, Erica Lay, Philip L. Ho, Keith S. Chan. Blocking wound-induced tumor repopulation between chemotherapy cycles as a novel approach to abrogate chemoresistance. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5470. doi:10.1158/1538-7445.AM2015-5470

Abstract 1928: Reporter construct for functional and real-time evaluation of cytokeratin 14+ bladder cancer stem cells

Bladder cancer is the fifth most common malignancy in the US. We recently reported that bladder cancer stem cells isolated by cell surface markers (i.e. CD44/CD90/CD49f) express a higher level of the intermediate filament cytokeratin 14 (CK14). Importantly, patients with a higher fraction of CK14+ cancer cells correlated with worse survival outcomes. Therefore, this CK14+ cancer cell subpopulation warrants further functional evaluation and characterization.

In the current study, we report the generation and characterization of a lentiviral reporter construct that carries the gene promoter region of human KRT14 gene upstream to a red fluorescent protein (tdTomato; Tm). With this reporter stably integrated into the genome of bladder cancer cells, the viable CK14+ cancer cell subpopulation could be isolated by FACS and visualized by fluorescent microscopy. We first validated the reporter by demonstrating that Tm+ cancer cells indeed express a higher level of KRT14 mRNA and relatively lower levels of differentiated cell markers (i.e. KRT18 and UPK1B) by qPCR. Next, we verified both in vitro and in vivo that CK14+/Tm+ cancer cells have functional properties of cancer stem cells by demonstrating their enriched sphere-forming ability and proficient engraftment as xenograft tumors in immunocompromised mice. Since neoadjuvant chemotherapy is a well-established treatment approach in patients with high-risk bladder cancer, we investigated CK14+ and CK14- cancer cells' response to the cytotoxic chemotherapy, gemcitabine/cisplatin (GC). FACS-purified CK14+/Tm+ cancer cells were more resistant to GC chemotherapy in vitro than CK14-/Tm- cancer cells. These findings were confirmed with in vivo studies using both patient-derived xenografts and immortalized bladder cancer xenografts. GC treated xenografts demonstrated a greater expansion of CK14+ cancer cells than vehicle treated controls. Additionally, we obtained a panel of human bladder cancer specimens from patients before and after neoadjuvant GC chemotherapy (n=15) and evaluated the CK14 status. An expansion or persistence of an infiltrating pattern of CK14 in post-neoadjuvant GC chemotherapy tumor specimens was associated with worse overall survival.

Collectively, these findings verified the unique intrinsic biological properties of CK14+/Tm+ bladder cancer cells and their response to GC chemotherapy. Ongoing experiments using fluorescence live imaging will evaluate Tm+/- bladder cancer cells' response to chemotherapy. The capacity to observe this CK14+/Tm+ subpopulation and their trace response to cytotoxic chemotherapy in these studies will open up new avenues to study the mechanisms of chemoresistance.

Citation Format: Philip L. Ho, Antonina Kurtova, Jing Xiao, Ross Krasnow, Erica Lay, Senthil Pazhanisamy, Seth P. Lerner, Keith S. Chan. Reporter construct for functional and real-time evaluation of cytokeratin 14+ bladder cancer stem cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1928. doi:10.1158/1538-7445.AM2014-1928

Specifications for hard condensed matter specimens for three-dimensional high-resolution tomographies

Tomography is a standard and invaluable technique that covers a large range of length scales. It gives access to the inner morphology of specimens and to the three-dimensional (3D) distribution of physical quantities such as elemental composition, crystalline phases, oxidation state, or strain. These data are necessary to determine the effective properties of investigated heterogeneous media. However, each tomographic technique relies on severe sampling conditions and physical principles that require the sample to be adequately shaped. For that purpose, a wide range of sample preparation techniques is used, including mechanical machining, polishing, sawing, ion milling, or chemical techniques. Here, we focus on the basics of tomography that justify such advanced sample preparation, before reviewing and illustrating the main techniques. Performances and limits are highlighted, and we identify the best preparation technique for a particular tomographic scale and application. The targeted tomography techniques include hard X-ray micro- and nanotomography, electron nanotomography, and atom probe tomography. The article mainly focuses on hard condensed matter, including porous materials, alloys, and microelectronics applications, but also includes, to a lesser extent, biological considerations.

Efficacy of topical aciclovir for the treatment of feline herpetic keratitis: results of a prospective clinical trial and data from in vitro investigations

This study aimed to evaluate the efficacy of topical ophthalmic aciclovir applied five times daily as a treatment for feline herpesvirus type 1 (FHV-1) keratitis in a group of cats in a first-opinion practice setting. Cats with ocular signs indicative of FHV-1 or Chlamydophila species infection, predominantly conjunctivitis and keratitis, were tested for FHV-1 antigen using an immunofluorescent technique on air-dried conjunctival swabs. They were first treated with topical chlortetracycline with efficacy against Chlamydophila species and then, in cases positive for FHV-1, with topical aciclovir. The time to recovery was determined and illustrated using a Kaplan-Meier plot. Three cats were infected with Chlamydophila species and showed a median time to recovery of 14 days (95 per cent confidence interval [CI] 10 to 18 days), while 30 cats infected with FHV-1 showed a median time to recovery of 12 days (95 per cent CI 10 to 14 days). The drug dose at which 50 per cent plaque reduction (ED50) occurred in a standard plaque reduction assay was determined in an in vitro study. This showed a mean (SD) ED50 of aciclovir of 25 (3.5) mg/ml compared with 0.4 (0.05) mg/ml for trifluorothymidine, a drug known to be efficacious against FHV-1. The study shows that even though aciclovir is generally considered to lack efficacy against ocular FHV-1 infection, when used frequently it can have a beneficial effect in FHV-1 conjunctivitis and keratitis.

Homogeneity of meats prepared for analysis with a commercial food processor: collaborative study

The food processor was evaluated as an alternative to the food chopper and bowl cutter for preparing meat samples for analysis in AOAC procedure 24.001. Samples of 6 meat types--cooked sausage, pork sausage, canned ham, hamburger, water-added ham, and smoked ham--were distributed to 9 laboratories for preparation using a food processor. The resulting 54 samples were sent to a USDA-accredited laboratory for analysis in triplicate for moisture, protein, and fat. Standard deviations and their 95% confidence intervals calculated for the analytical results were compared with USDA Performance Standards. With few exceptions, the upper limits were lower than the Performance Standards and for the exceptions, the intervals included the Performance Standards. By these criteria, the food processor is as effective in preparing homogeneous samples as the preparation procedures used to set the Performance Standards. Collaborators found the processor faster to use and easier to clean than the food chopper. Use of the food processor has received interim approval as an alternative to the food chopper or bowl cutter in AOAC procedure 24.001 for preparing meat samples for analysis.

Characterization of latent infections in mice inoculated with herpes simplex virus which is clinically resistant to acyclovir

Mice were inoculated into the ear pinna with herpes simplex virus (HSV) using a strain which is resistant to acyclovir (ACV) chemotherapy. The original inoculum was resistant to ACV because it contained a proportion of thymidine kinase-defective (TK-) virions. This had been obtained previously by passage of an HSV type 1 strain in mice undergoing suboptimal therapy. The cervical dorsal root ganglia were subsequently explanted from the infected mice and the presence of latent virus therein revealed by reactivation in vitro. These explant cultures yielded both TK+ and TK- viruses on reactivation. The establishment of latent infections was not affected by chemotherapy during the acute infection. One TK- ganglion isolate when studied in detail was found to be attenuated and thus resembled previously examined TK- strains which had been selected in vitro for ACV-resistance.