In vivo conversion of Müller glia
into photoreceptors through cell fusion - mediated reprogramming.
His research is focused on retinal regeneration by reprogramming human fibroblasts either into induced pluripotent stem cells or directly
into photoreceptors.
Lamba and colleagues recently demonstrated that human embryonic stem cells could be directed to differentiate
into photoreceptors and respond to a light stimulus as measured by ERG in crx − / − mice (a model for Leber's congenital amaurosis)[5].
Not exact matches
When light enters the retina,
photoreceptor cells translate it
into electrical signals.
Among the disorders that Balasubramanian has targeted is retinitis pigmentosa, a group of inherited diseases that cause degeneration of the retina (in the back of the eye where millions of
photoreceptors capture light rays that the brain turns
into images).
Once such mutation prevents the production of an enzyme needed to break down retinol, a form of vitamin A,
into a substance that
photoreceptors need to detect light and send signals to the brain.
The artificial retina then converts the signal
into electrical impulses, which bypass damaged
photoreceptors and stimulate the retina's remaining cells.
Surgeons will inject the cells
into the retina in the space usually occupied by RPEs, directly adjacent to the
photoreceptor cells.
Through the same viral strategy, both
photoreceptor types were then introduced
into neurons.
«The goal is to halt the rate of
photoreceptor loss,» says Robert Lanza, chief scientist at Advanced Cell Technology (ACT) of Worcester, Massachusetts, the company that has been developing the treatment since first turning hESCs
into RPEs in 2004.
Some scientists are trying to inject signaling molecules
into the eye to stimulate light - collecting
photoreceptor cells to regrow.
The
photoreceptors in the retina, at the back of the eyes, are the primary light sensitive cells that allow us to see: they convert light
into electrical signals.
At the top of the image are the retina's
photoreceptor cells (in gray)-- the familiar rods and cones — that capture photons of light and translates them
into electrical currents.
By studying what pushes those 6 percent
into their fate as
photoreceptor cells, researchers might figure out how to generate a larger number of transplantable cells.
In people with these conditions the
photoreceptors, which transform light hitting the eye
into electrical impulses, are damaged, preventing the brain from receiving image information.
Ortega - Hernández observed that bright spots at the front of the bodies, which are in fact simple
photoreceptors, are embedded
into the anterior sclerite.
Their findings suggest that even the earliest animals had the makings of both vertebrate and invertebrate visual systems, and that some of the
photoreceptor cells in the invertebrate brain were transformed through a series of steps
into vertebrate eyes.
Detlev Arendt and Joachim Wittbrodt, developmental biologists at the European Molecular Biology Laboratory in Heidelberg, Germany, jumped
into the fray after Arendt noticed some vertebrate - like
photoreceptor cells in the brains of ragworms, a marine species that hasn't changed much for 500 million years.
The therapy employs a virus to insert a gene for a common ion channel
into normally blind cells of the retina that survive after the light - responsive rod and cone
photoreceptor cells die as a result of diseases such as retinitis pigmentosa.
In people with these conditions the retina's
photoreceptors — which transform light hitting the eye
into electrical impulses — are often damaged, preventing visual information from being sent to the brain.
Some of the cells in this layer (the
photoreceptors) convert light
into an electrical signal that is then amplified and processed by other cells before being sent to the brain via the optic nerve.
There are even efforts underway to transplant cultured
photoreceptor cells
into the retina to replace those lost from advanced disease.
Genetic defects cause
photoreceptor degeneration, which are majorly classified
into rod - cone dystrophy called retinitis pigmentosa (rods initially degenerate, followed by cone degeneration), cone - rod dystrophy (cone degeneration, followed by rod degeneration), and Leber congenital amaurosis (LCA).
New information about how light energy is changed
into neural signals shows how an individual
photoreceptor cell of the eye registers the absorption of a single photon, or quantum of light
However, both Goldberg and Albini agreed there is no evidence that this kind of therapy could have treated the patients» sight problems even if carried out correctly and only sparse evidence that adipose cells can differentiate
into retinal pigment epithelium or
photoreceptor cells, which play a critical role in macular degeneration.
Human - induced pluripotent stem (iPS) cells can be directed to develop
into light - sensing
photoreceptor cells of the retina.
When transplanted to the subretinal space of mice lacking functional
photoreceptors, human embryonic stem cells directed toward a retinal lineage integrate
into the outer nuclear layer, express
photoreceptor markers, and restore a light response as determined by the electroretinogram (ERG)[5].
Rod and cone
photoreceptors in the outer retina transduce light
into electrical signals.
Human ES cells treated with Noggin, Dickkopf - 1, and Insulin - like Growth Factor - 1 proteins differentiate
into functional
photoreceptors [5].
Photoreceptors are specialized neurons in the retina that convert light
into signals that the brain interprets as sight.
The apical domain can be further subdivided
into spatially and functionally distinct regions, nicely seen in
photoreceptor cells, where the apical domain is further subdivided
into the rhabdomere and the stalk membrane (green and magenta, respectively, in Fig.
The team transplanted stem cell - derived
photoreceptors into another strain of mouse, called CRX null, which is congenitally blind.
Lanza's team figured out how to coax stem cells taken from human embryos
into becoming the RPE cells that die off along with
photoreceptors in macular degeneration, and in 2011 the team began injecting these manufactured cells
into patients» eyes.
GenSight's treatment is for people with damaged
photoreceptor cells but intact ganglion cells; it inserts the gene
into the ganglion cells, whose axons form the basis of the optic nerve.
These cells can develop
into any type of retinal cell, including RPE cells or
photoreceptors.
The treatment makes these ganglion cells act like
photoreceptors, responding to patterns of light that pass through the retina and converting them
into patterns of electricity that go directly to the brain.
The macula is densely packed with
photoreceptor cells called rods and cones that react to light and send electrical nerve impulses to the optic nerve and
into the brain.
In the past, neural stem and progenitor cells from various sources were introduced
into eyes with the thought that they might differentiate and replace
photoreceptors lost in retinal disease [13]--[19].
These cells protect and nourish the retina, remove waste products, prevent new blood vessel growth
into the retinal layer, and absorb light not absorbed by the
photoreceptor cells; these actions prevent the scattering of the light and enhance clarity of vision.
iPS - RPE cells were injected
into the subretinal space between the host RPE and
photoreceptor cells (B) A layer of iPS - RPE cells in the subretinal space of the dystrophic RCS rat 20 hours following transplantation.
Subretinal transplantation of MACS purified
photoreceptor precursor cells
into the adult mouse retina.
iPS - RPE are capable of phagocytosing
photoreceptor material, in vitro and in vivo following transplantation
into the Royal College of Surgeons (RCS) dystrophic rat.
In vitro expanded stem cells from the developing retina fail to generate
photoreceptors but differentiate
into myelinating oligodendrocytes.
These are the
photoreceptor support cells in the retina that are critical for the process of light
into sight conversion.