IRB Barcelona has identified GEMC1 as a master gene for the generation of multiciliated cells—cells with fine filaments that move fluids and substances—which are found exclusively in the brain, respiratory tract, and reproductive system.

Defects in multiciliated cells lead to ciliopathies—rare and complex diseases that are poorly understood and for which not all causative genes have been identified.

The genomic sequencing of hundreds of patients with diverse types of ciliopathies has revealed that “in many cases the gene responsible is not known”, says Travis Stracker, head of the Genomic Instability and Cancer Lab at the IRB Barcelona. “So many people do not have a molecular diagnosis,” stresses the researcher. “Our work seeks to contribute to bridging this knowledge gap”.

A study on mice by Travis Stracker and his team, in collaboration with Vincenzo Costanzo’s laboratory at the FIRC Institute of Molecular Oncology (IFOM) in Milan, in which they reveal a gene candidate for a subtype of human ciliopathy. The gene in question, GEMC1, is indispensable for the generation of multiciliated cells specific to tissues such as the brain, trachea, lungs and oviducts.

The surface of multiciliated cells is covered by hundreds of cilia. These tiny, hairlike structures serve to circulate cerebrospinal fluid, remove mucus from the respiratory tract, and transport ovum through the oviduct, among other functions. Defects in the generation or function of these cells causes a subtype of ciliopathies called Mucociliary Clearance Disorders.

Specifically, GEMC1-deficient mice produced by Stracker reproduce the symptoms of a rare disease called RGMC (Reduced Generation of Multiple Motile Cilia)—a condition that causes hydrocephaly, severe respiratory infections, and infertility. The work, led by IRB Barcelona PhD student Berta Terré and IFOM postdoctoral researcher Gabriele Piergiovanni, reports that GEMC1 regulates the only two genes known to date that underlie this disease, Multicilin and Cyclin O, thus making it a potential candidate gene for RGMC.

In addition, the study has revealed that GEMC1 is one of the most important genes in the gene signalling cascade for the production of multiciliated cells. This means that this gene affects many others that depend on its expression. The gene expression analysis of this first study has revealed at least 10 new candidate genes related to cilia, as well as dozens that were already known or suspected of being involved in the function of cilia. IRB Barcelona

Male breast cancer (MBC) is a very rare tumour type, occurring in just 1% of all breast cancer cases, and the underlying genetic causes and treatment of MBC is not well understood. In a paper, researchers from Italy and the U.S. describe novel genetic variants found in a hormone receptor positive (HR+) MBC patient, that are distinct from previously identified genetic variants found in ten MBC cases.

The authors present the treatment history of a HR+ male breast cancer patient. His disease stabilized from targeting of the PI3K/mTOR pathway using the PI3K/mTOR inhibitor BEZ235 in combination with everolimus as 3rd line treatment for his metastatic ductal carcinoma and experienced a prolonged stable disease. After 18 months he subsequently became resistant to the treatment and his disease progressed. The authors then investigated why the patient benefited and subsequently developed resistance to this combination treatment using genomic and immunohistochemical analysis.

Whole-exome sequencing was performed on pre-treatment and post-progression samples of the MBC patient, as compared to a whole blood normal control. The researchers found that a region of Chromosome 12p was deleted in the resistant tumour and that HR protein expression was increased in the resistant tumour. This research provides new insights into both male breast cancer and response to BEZ235/everolimus combination treatment. This study adds to our understanding of MBC development and resistance, and the authors commented that ”Breast cancer in men is a very rare disease, representing less than 1% of all breast cancer cases. So, very few and small studies have been conducted in this disease. Our analyses contributed to delineate the genomic landscape of male breast cancer and suggested a potential particular benefit in this disease by the combined treatment with Afinitor plus BEZ235 in order to achieve a complete blockade of the PI3K/Akt/mTOR pathway. University of Verona

ELISA and indirect immunofluorescence tests (IIFT) have been developed for sensitive and specific detection of antibodies against Zika virus in patient serum samples. The assays are suitable for diagnosing acute infections as well as for disease surveillance. In particular, serological analyses can aid the differentiation of infections with Zika virus, dengue virus and chikungunya virus, which manifest with similar symptoms and are endemic in much the same geographic regions. Anti-Zika Virus ELISA (IgM or IgG) are based on highly specific recombinant Zika NS1 protein which avoids cross reactivity with other flaviviruses. Data from panels of well characterized sera have confirmed that there is no cross reactivity with flaviviruses including dengue, West Nile, yellow fever and Japanese encephalitis viruses. In studies on clinically and serologically characterized samples the IgM and IgG ELISA showed 100% sensitivity and 100% specificity. Anti-Zika Virus IIFT (IgM or IgG) utilize Zika virus-infected cells as the antigenic substrate. Positive and negative results are evaluated by fluorescence microscopy. With the Arboviral Fever Mosaic 2 the Zika virus substrate is incubated in parallel with substrates for chikungunya virus and dengue virus serotypes 1 to 4. This BIOCHIP combination can help in the differential diagnosis of Zika, dengue and chikungunya virus infections. Due to the use of whole virus particles, cross reactivities between flavivirus antibodies can occur. Serological tests provide a longer window for diagnosis than direct detection methods, which are only effective during the viremic phase within the first week after onset of symptoms. Detection of specific IgM or a significant rise in specific IgG in a pair of samples taken seven to ten days apart is evidence of an acute infection. Serological analyses are also important for prenatal monitoring, screening of donated blood and epidemiological studies. Zika virus is the pathogenic agent of Zika fever, an infectious topical disease which manifests with fever, exanthema and arthritis. Zika virus infection has been linked to congenital malformations, in particular microcephaly, and neurological complications such as Guillain-Barré syndrome. The virus is transmitted by mosquitoes of the Aedes family. Zika virus is currently spreading explosively in the Americas.

Euroimmunwww.euroimmun.de

Researchers from the University of Illinois at Urbana-Champaign have developed a highly sensitive biosensor based on a differential immuno-capture technology that can detect sub-populations of white blood cells. As part of a small, disposable biochip, the microfluidic biosensor can count CD4+/CD8+ T cells quickly and accurately for AIDS diagnosis in the field.  

“There are 34 million people infected with HIV/AIDS worldwide, many in places that lack testing facilities,” explained Rashid Bashir, an Abel Bliss Professor of Engineering and head of the Department of Bioengineering at Illinois.

“An important diagnostic biomarker for HIV/AIDS is the absolute count of the CD4+ and CD8+ T lymphocytes in the whole blood. The current diagnostic tool—a flow cytometer—is expensive, requires large blood volume, and a trained technician to operate,” Bashir said. “We have developed a microfluidic biosensor based on a differential immuno-capture electrical cell counting technology to enumerate specific cells in 20 minutes using 10 microliters of blood.” (There are about 50 microliters in a drop of blood). 

Human blood is composed of 45 percent of cells with 5 million erythrocytes as compared to only 7000 leukocytes in one microliter of blood. Specific leukocytes like CD4 T cells are of the order of 50-1000 cells per microliter. Electrical cell counting can differentiate cells based on size and membrane properties depending on the frequency of the interrogation signal. However, differentiating cells of same morphology is a challenge.
“For example, a CD4+ T lymphocyte can’t be differentiated from CD4- lymphocytes just by electrical interrogation,” stated Umer Hassan, a postdoctoral researcher in the Bashir’s group and first author of the paper.

“In response to this challenge, we had developed a technique to selectively deplete target leukocytes,” Hassan added. “And our biochip takes whole blood as input, eliminating the need of off-chip sample preparation and effectively reducing the assay time as well.”

In addition to the microfluidic “capture chamber,” the new chip incorporates separate ports for lysing reagents and quenching buffers that preserve the leukocytes for counting by the microfabricated electrodes. Specific leukocytes like CD4 T cells get captured as they interact with the antibodies in the capture chamber; a  second counter recounts the remaining leukocytes. The difference in the respective cell counts give the concentration of the cells captured.

In clinical trials, the differential immuno-capture biochip achieved more than 90 per cent correlation with a flow cytometer for both CD4 T cells for CD8 T cell counts using HIV infected blood samples. The biochip can also be adapted to enumerate other specific cell types such as somatic cells or cells from tissue or liquid biopsies.

The novel biosensor has the potential to be an automated portable blood cell counter for point-of-care applications in developed and resource-limited regions worldwide. Bashir’s group is working on miniaturizing the setup to make the technology handheld, as well as designing a cartridge that can be mass-produced. Engineering at Illinois

An international team of scientists has identified novel gene locations associated with childhood body mass index (BMI)—an important measurement related to childhood obesity. The meta-analysis, covering over 47,000 children, is the largest genetic study to date of childhood BMI.

“Although investigators have found many genes associated with adult BMI, the genetics of childhood BMI has remained largely unknown,” said Struan F.A. Grant, PhD, a genomics researcher at The Children’s Hospital of Philadelphia (CHOP), and one of three co-senior authors of the study. “Given the fact that childhood obesity is an important concern in public health, identifying specific genetic influences could prove useful in designing future preventive interventions and treatments for children.”

The meta-analysis covered 33 genome-wide association studies, including a total of over 45,000 children, all of European ancestry. Of that total, there were 35,668 children from 20 studies in the discovery phase, and 11,873 children from 13 replication studies. The researchers found 15 genomic regions associated with childhood BMI, three of which were novel.

In all, the 15 risk-susceptibility loci account for 2 percent of the variance in childhood BMI. Despite this small proportion, said Grant, it provides crucial novel insight into the biology of obesity and provides opportunities for generalized therapeutic intervention. The 12 previously discovered genetic loci were shared between both adults and children with high BMI. The large overlap, said the authors, suggests that the genetic variants may not exert their effects only in childhood, but may have different effects at different ages.

Grant added that further research may determine whether the three novel loci the study group discovered influence BMI only in childhood, or whether their effects are stronger during childhood.

The current study, said Grant, dovetails with a 2012 meta-analysis he led for the EGG Consortium. That research was the largest genome-wide study of common childhood obesity. “Obviously, much research remains to be done,” said Grant, who added, “As we continue to identify gene variants implicated in paediatric obesity and body mass, we are laying a foundation for research that could provide useful biological targets for better treating childhood obesity, and its negative health consequences.” The Children’s Hospital of Philadelphia