The National Institutes of Health in September allocated nearly $2 million in grant funding to support six research projects focusing on microRNAs in the brain and their relationship to conditions including schizophrenia, glioblastoma, and Alzheimer's disease.
The first grant went to Advanced Genomic Technology, a Louisville, Ky.-based diagnostics firm developing a miRNA-based blood test for determining the risk of mild cognitive impairment, or MCI, converting into Alzheimer's disease.
While a professor at McGill University, AGT founder Eugenia Wang published data showing that miRNA signatures could be obtained from blood samples of elderly Alzheimer's disease patients and used to differentiate them from normal elderly controls.
Additional work indicated that one specific miRNA — miR-181b — is upregulated in MCI patients who do not develop Alzheimer's disease, while two others — miR-34a and miR-34c — are upregulated only in MCI patients who later convert to Alzheimer's disease.
With the NIH funding, the company plans to examine blood samples from 30 patients with MCI, 30 normal elderly individuals, and 30 patients with Alzheimer's disease in order to establish the reproducibility of its miRNA assays and to optimize assay protocols, according to the grant's abstract. AGT also aims to further validate the roles of the three miRNAs previously identified, as well as to identify other potential miRNA biomarkers.
Should these studies be successful, AGT plans to further study the miRNAs in a larger number of patients and controls, and see whether they can serve as biomarkers for other non-Alzheimer's disease dementias including Parkinson's disease.
The six-month grant is worth $199,666.
Also pulling in NIH funding is Los Angeles-based startup Nesher Technologies, which is developing diagnostics using an alternating laser excitation fluorescence spectroscopy-based biodetection technology licensed from the University of California, Los Angeles.
According to the company, the approach involves target recognition molecules that are tagged with different color fluorescent dyes and quenchers, which allows ultrasensitive detection of both proteins and nucleic acids in body fluids — all on the same platform.
With the NIH grant, Nesher plans to develop and validate an assay that will use a panel of proteins and miRNAs to diagnose early-stage Alzheimer's disease, and then test the approach in a collection of clinical samples from 108 patients, according to grant's abstract.
Upon the successful completion of this work, the company aims to further expand the assay and miniaturize it for easier use in a clinical setting.
Nesher's grant began on Sept. 1 and runs until May 31, 2015. It is worth $228,666 in its first year.
Meanwhile, University of Kentucky investigator Peter Nelson was awarded a two-year grant to test his hypothesis that a specific miRNA, miR-497, contributes to sexually dimorphic dementia with Lewy bodies, a condition with symptoms similar to Parkinson's disease that affects men significantly more than women.
In preliminary studies, Nelson and his colleagues found that miR-497 is expressed in a sexually dimorphic manner in both the human brain and in rat primary cultured neurons, and that the miRNA is enriched in human brains with Lewy body pathology and in vulnerable brain areas, he wrote in the grant's abstract. Further, miR-497 expression in cultured cells alters the production of alpha-synuclein, which accumulates in the brains of patients, as well as expression of a gene known to be dysregulated in a subtype of Parkinson's disease.
With the NIH grant, Nelson and his lab plan to confirm whether miR-497 is sexually dimorphically expressed in human brain, and if it is dysregulated in human brains with Lewy body pathology.
They then will test whether the miRNA regulates alpha-synuclein expression by transducing primary rat neurons with lentiviral vectors expressing either miR-497 or control miRNAs, and determine the full list of miR-497 targets in cultured primary neurons, according to the abstract.
The grant began on Sept. 1 and is worth $225,000 in its first year.
In light of data from multiple groups linking miRNA dysregulation with schizophrenia in both human and mouse brain tissue, University of Florida researcher Brooke Miller recently analyzed the expression of more than 800 of the small, non-coding RNAs in prefrontal cortical tissue from control and schizophrenic patients, identifying one — miR-132 — that was significantly downregulated.
Having confirmed the finding in a separate schizophrenia patient population, and with the help of an NIH grant, she and her colleagues now aim to identify the miRNA's protein-coding targets that have "direct biological relevancy to schizophrenia using a combination of bioinformatics and in vitro cell biology," she wrote in her grant's abstract.
In animal models, changes in schizophrenia-like behaviors will be characterized following inhibition of miR-132 function in the prefrontal cortex during the early postnatal period, and the miRNAs function will be manipulated "multiple developmental stages and characterize the effects on behavior, neuromorphology, and neuronal function in the adult," the abstract adds.
The grant kicked off on Sept. 15 and runs until May 31, 2016. It is worth $249,000 in the first year.
Also receiving NIH support is Mount Sinai School of Medicine researcher Kristen Brennand, who is examining child-onset schizophrenia and the potential role of miRNAs in the rare disorder.
Previously, she and her colleagues reprogrammed fibroblasts from schizophrenia patients into human-induced pluripotent stem cells, then differentiated these disorder-specific stem cells into neurons, she wrote in her grant's abstract, noting that neurons arising from schizophrenia patient stem cells have "reduced neuronal connectivity and altered gene expression relative to controls."
Because gene expression profiles of these human-induced pluripotent stem cell-derived neural cells "most resemble first trimester neural tissue," she and her team see them as ideal for studying the embryonic development effects that contribute to diseases such as child-onset schizophrenia.
With the NIH grant, Brennand aims to analyze mRNA and miRNA expression in these neuronal cells, moving on to mechanistic studies of miRNA candidates identified, with the goal of gaining molecular insights into child-onset schizophrenia that may be applicable to the disease as a whole.
Her grant began on Sept. 1 and runs until Aug. 31, 2018. It is worth $432,191 in the first year.
Having generated data indicating that miRNAs are implicated in glioblastoma growth and invasiveness, and showing that these tumors excrete microvesicles containing high levels of the non-coding RNAs, Massachusetts General Hospital's Xandra Breakefield and colleagues at Harvard University have received an NIH grant to see whether such cancer-derived molecules affect the physiology of healthy brain tissue.
According to the grant's abstract, the investigators suspect that such miRNA-mediated regulation of gene expression in the cells surrounding glioblastomas "may lead to transformative events in the brain cells, serving either protective or, ultimately, tumor growth-supportive function."
To test this idea, they plan to characterize intracellular and extracellular RNA in human and mouse glioblastoma cells, as well as intracellular RNA in normal brain cells that constitute the cancer's microenvironment.
They then will examine miRNA transfer between glioblastoma and normal cells in vitro and its functional effects on the phenotypes of the recipient cells, according to the grant's abstract. Finally, they will investigate whether miRNA transfer exists between the xenograft glioblastoma models and normal brain cells in animals in vivo.
The grant began on Sept. 1 and runs through Aug. 31, 2018. It is worth $414,537 in the first year.