Stories about: neurons

Maintaining mitochondria in neurons: A new lens for neurodegenerative disorders

cartoon of mitochondria being transported in neurons - part of mitostasis
In some neurons, mitochondria must travel several feet along an axon. (Elena Hartley illustration)

Tom Schwarz, PhD, is a neuroscientist at Boston Children’s Hospital’s F.M. Kirby Neurobiology Center, focusing on the cell biology of neurons. Tess Joosse is a biology major at Oberlin College. This article is condensed from a recent review article by Schwarz and Thomas Misgeld (Technical University of Munich).

Like all cells, the neurons of our nervous system depend on mitochondria to generate energy. Mitochondria need constant rejuvenation and turnover, and that’s especially true in neurons because of their high energy needs for signaling and “firing.” Mitochondria are especially abundant at presynaptic sites — the tips of axons that form synapses or junctions with other neurons and release neurotransmitters.

But the process of maintaining mitochondrial number and quality, known as mitostasis, also poses particular challenges in neurons. Increasingly, mitostasis is providing a helpful lens for understanding neurodegenerative disorders. Problems with mitostasis are implicated in Parkinson’s disease, Alzheimer’s disease, ALS, autism, stroke, multiple sclerosis, hypoxia and more.

Read Full Story | Leave a Comment

Lab-grown human cerebellar cells yield clues to autism

This Purkinje cell, made from a patient with tuberous sclerosis, will enable study of autism disorders. (Credit: Maria Sundberg)

Autism spectrum disorder (ASD) is increasingly linked with dysfunction of the cerebellum, but the details, to date, have been murky. Now, a rare genetic syndrome known as tuberous sclerosis complex (TSC) is providing a glimpse.

TSC includes features of ASD in about half of all cases. Previous brain autopsies have shown that patients with TSC, as well as patients with ASD in general, have reduced numbers of Purkinje cells, the main type of neuron that communicates out of the cerebellum.

In a 2012 mouse study, team led by Mustafa Sahin, MD, at Boston Children’s Hospital, knocked out a TSC gene (Tsc1) in Purkinje cells. They found social deficits and repetitive behaviors in the mice, together with abnormalities in the cells.

The new study, published last week in Molecular Psychiatry, takes the research into human cells, for the first time creating cerebellar cells known as Purkinje cells from patients with TSC.

Read Full Story | Leave a Comment

Mutations accumulate in our brain cells as we age. Do they explain cognitive loss?

the aging brain - do DNA mutations in neurons account for cognitive loss?

Scientists have long wondered whether somatic, or non-inherited, mutations play a role in aging and brain degeneration. But until recently, there was no good technology to test this idea.

Enter whole-genome sequencing of individual neurons. This fairly new technique has shown that our brain cells have a great deal of DNA diversity, making neurons somewhat like snowflakes. In a study published online today in Science, the same single-neuron technique provides strong evidence that our brains acquire genetic mutations over time.

Read Full Story | Leave a Comment

New Human Neuron Core to analyze ‘disease in a dish’

Human Neuron CoreLast week was a good week for neuroscience. Boston Children’s Hospital received nearly $2.2 million from the Massachusetts Life Sciences Center (MLSC) to create a Human Neuron Core. The facility will allow researchers at Boston Children’s and beyond to study neurodevelopmental, psychiatric and neurological disorders directly in living, functioning neurons made from patients with these disorders.

“Nobody’s tried to make human neurons available in a core facility like this before,” says Robin Kleiman, PhD, Director of Preclinical Research for Boston Children’s Translational Neuroscience Center (TNC), who will oversee the Core along with neurologist and TNC director Mustafa Sahin, MD, PhD, and Clifford Woolf, PhD, of Boston Children’s F.M. Kirby Neurobiology Center. “Neurons are really complicated, and there are many different subtypes. Coming up with standard operating procedures for making each type of neuron reproducibly is labor-intensive and expensive.”

Patient-derived neurons are ideal for modeling disease and for preclinical screening of potential drug candidates, including existing, FDA-approved drugs. Created from induced pluripotent stem cells (iPSCs) made from a small skin sample, the lab-created human neurons capture disease physiology at the cellular level in a way that neurons from rats or mice cannot.

Read Full Story | Leave a Comment

Modeling pain in a dish: Nociceptors made from skin recreate pain physiology

Pain in a dish nociceptors

Chronic pain, affecting tens of millions of Americans alone, is debilitating and demoralizing. It has many causes, and in the worst cases, people become “hypersensitized”—their nervous systems fire off pain signals in response to very minor triggers.

There are no good medications to calm these signals, in part because the subjectivity of pain makes it difficult to study, and in part because there haven’t been good research models. Drugs have been tested in animal models and “off the shelf” cell lines, some of them engineered to carry target molecules (such as the ion channels that trigger pain signals). Drug candidates emerging from these studies initially looked promising but haven’t panned out in clinical testing.

Read Full Story | Leave a Comment

The 98%: Proteomics reveals proteins made from ‘noncoding’ DNA

proteins and peptides from noncoding DNA
Probing the genome's 'dark side' could change our view of biology.
Vast chunks of our DNA—fully 98 percent of our genome—are considered “non-coding,” meaning that they’re not thought to carry instructions to make proteins. Yet we already know that this “junk DNA” isn’t completely filler. For example, some sequences are known to code for bits of RNA that act as switches, turning genes on and off.

New research led by Judith Steen, PhD, and Gabriel Kreiman PhD, of Boston Children’s Hospital’s Proteomics Center and Neurobiology program, goes much further in mapping this “dark side” of the genome.

In a report published last month in Nature Communications, they describe a variety of proteins and peptides (smaller chains of amino acids) arising from presumed non-coding DNA sequences. Since they looked in just one type of cell—neurons—these molecules may only be the tip of a large, unexplored iceberg and could change our understanding of biology and disease.

Read Full Story | Leave a Comment