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Category: genetics – Page 113

Genetically engineered T cells for cancer immunotherapy

Relying on sub-wavelength nanostructures, metasurfaces have been shown as promising candidates for replacing conventional free-space optical components by arbitrarily manipulating the amplitude, phase, and polarization of optical wavefronts in certain applications1,2,3. In recent years, the scope of their applications has been expanded towards complete spatio-temporal control through the introduction of active metasurfaces. These developments open up exciting new possibilities for dynamic holography4, faster spatial light modulators5, and fast optical beam steering for LiDAR6. Large efforts have been channeled into various modulation mechanisms7. Microelectromechanical and nanoelectromechanical systems (MEMS and NEMS)8,9,10,11 have the advantages of low-cost and CMOS-compatibility, but the speed is limited up to MHz. Phase-change materials12,13,14 have fast, drastic, and non-volatile refractive index change, but lack continuous refractive index tuning and have a limited number of cycles constraining applicability to reconfigurable devices. Through molecule reorientation, liquid crystal can have index modulation over 10%, while under relatively low applied voltages Tunable liquid crystal metasurfaces, U.S. patent number 10,665,953 [Application Number 16/505,687]15. Techniques of liquid crystal integration have also advanced after decades of development. However, the tuning speeds are limited to kHz range16. Thermal-optic effects can induce relatively large refractive index changes17,18, but the speed is inherently limited and the on-chip thermal management can be challenging. The co-integration of transparent conductive oxide and metallic plasmonic structures5,6 has been demonstrated in epsilon-near-zero (ENZ) regime to control the wavefront of reflected light, but the low reflection amplitude induced by the optical loss of the materials and the ENZ regime is unavoidable.

In modern photonics, a multitude of technologies for tunable optics and frequency conversion19,20 are realized with nonlinear materials that have low loss and a strong χ effect, such as lithium niobate21,22, aluminum nitride23, and organic electro-optic (OEO) materials24. Their ultrafast responses make it possible to use RF or millimeter-wave control25. Developments in computational chemistry have also led to artificially engineered organic molecules that have record-high nonlinear coefficients with long-term and high-temperature stability26,27. However, their potential in modifying free-space light has been relatively unexplored until recently. Several OEO material-hybrid designs have demonstrated improved tunability of metasurfaces28,29,30. Utilizing dielectric resonant structures and RF-compatible coplanar waveguides, a free-space silicon-organic modulator has recently accomplished GHz modulation speed31. However, all demonstrations to date require high operating voltages ± 60V, due to low resonance tuning capability (frequency shift / voltage), which hinders their integration with electronic chips.

In this work, we propose combining high-Q metasurfaces based on slot-mode resonances with the unique nano-fabrication techniques enabled by OEO materials, which drastically reduces the operating voltage. The low voltage is mainly achieved from the ability to place the electrodes in close proximity to each other while hosting high-Q modes in between and the large overlap of the optical and RF fields in OEO materials. In the following sections, we first provide the design concepts and considerations for achieving a reduced operating voltage. Next, we numerically demonstrate the advantage of a particular selected mode compared to other supported modes in the structure. Finally, we experimentally realize our concepts and characterize the performance of the electro-optic metasurface.

The Genetics of Epilepsy

Our knowledge of the role of genetics in epilepsy is rapidly expanding, and this is enhancing epilepsy diagnosis, prognosis, and treatment. Julie Ziobro, MD, PhD is a pediatric epileptologist and research scientist at C.S. Mott Children’s Hospital. She and genetic counselor, Mallory Wagner, MS, LCGC, discuss some basic principles of genetics, currently available genetic tests, examples of genetic epilepsies, and how genetic test results can impact treatment decisions and prognosis. They also explore the role of genetics in developing precision therapies for epilepsy.

What is in utero gene editing?

Recently approved gene therapies offer patients one-time, potentially curative treatments for genetic diseases such as sickle cell anemia and beta thalassemia. But “one-time” miracle solutions can often be multi-month affairs, require millions of dollars, and cause painful side effects. What if that doesn’t have to be the case?

In utero gene editing, or prenatal somatic cell genome editing, envisions treating a fetus diagnosed with a genetic disease before birth, thereby preventing that entire protocol and the onset of symptoms in the first place. It would also challenge the need for the ethically fraught enterprise of embryo editing, as the treatment would only make edits in the DNA of the individual fetus — edits which would not be passed on in a heritable way.

Watch this video to learn more about in utero gene editing, how it works, and why scientists believe it might be an advantageous approach to treating certain genetic diseases.

Korea University study explores a novel and precise mitochondrial gene editing method

Gene editing technology could revolutionize the treatment of genetic diseases, including those that affect the mitochondria—cell structures that generate the energy required for the proper functioning of living cells in all individuals. Abnormalities in the mitochondrial DNA (mtDNA) could lead to mitochondrial genetic diseases.

Targeted base editing of mammalian mtDNA is a powerful technology for modeling mitochondrial genetic diseases and developing potential therapies. Programmable deaminases, which consist of a custom DNA-binding protein and a nucleobase deaminase, enable precise mtDNA editing.

There are two types of programmable deaminases for genome editing: cytosine base editors and adenine base editors, such as DddA-derived cytosine base editors (DdCBEs) and transcription activator-like effector (TALE)-linked deaminases (TALEDs). These editors bind to specific DNA sites in the mitochondrial genome and convert bases, resulting in targeted cytosine-to-thymine (C-to-T) or adenine-to-guanine (A-to-G) conversions during DNA replication or repair. However, the current gene editing approaches have many limitations, including thousands of off-target A-to-G edits while using TALEDs.

New insight into gene uncovers its link to incurable birth defect

Researchers have unraveled how mutations in a gene can lead to an incurable neurodevelopmental disorder that causes abnormal brain development in newborns and infants.

The WEHI study is the first to prove that a protein called Trabid helps control , and that mutations to this protein can lead to —a condition where a baby’s brain is smaller than expected.

It’s hoped the milestone findings will provide a deeper understanding into the protein’s impact on and lead to treatments that can slow or stop the development of microcephaly and potentially other neurological disorders.

What is Lynch syndrome, the hereditary condition that raises bowel cancer risk before 50?

“Lynch syndrome also known as HNPCC (Hereditary Non-Polyposis Colorectal Cancer) is an autosomal dominant condition that increases the risk of developing certain cancers, particularly bowel cancer. It results from mutations in genes that help to correct errors during DNA replication. Lynch syndrome patients have a higher incidence of bowel cancer in their lifetime and such other cancers as endometrial, ovarian, stomach and urinary tract cancers. These patients have an earlier presentation, i.e. younger age group. People with this condition face a much higher risk of developing colorectal cancer at ages below 50 years. This underscores the need for an early diagnosis through screening and surveillance in individuals having Lynch syndrome so that it can be detected rather earlier when it would be more easily treatable,” says Dr Tanveer Abdul Majeed, Consultant, Surgical Oncology, Kokilaben Dhirubhai Ambani Hospital Navi Mumbai.

“To effectively tackle Lynch syndrome-related cancers, early detection is vital. Screening protocols typically involve genetic testing to identify individuals at risk and surveillance measures, such as regular colonoscopies, starting at a younger age. Genetic counselling plays a pivotal role in Lynch syndrome management, providing affected individuals and their families with personalized risk assessments, guidance on screening strategies, and support in making informed decisions regarding preventive measures, including prophylactic surgery,” says Dr Kanuj Malik, Sr. Consultant-Surgical Oncology, Yatharth Hospitals.

ADHD linked to evolutionary success in ancient humans

While current diagnostic definitions of attention-deficit hyperactivity disorder (ADHD) are relatively new, the general condition has been identified by clinicians under a variety of names for centuries. Recent genetic studies have revealed the condition to be highly heritable, meaning the majority of those with the condition have genetically inherited it from their parents.

Depending on diagnostic criteria, anywhere from two to 16% of children can be classified as having ADHD. In fact, increasing rates of diagnosis over recent years have led to some clinicians arguing the condition is overdiagnosed.

What is relatively clear, however, is that the behavioural characteristics that underpin ADHD have been genetically present in human populations for potentially quite a long time. And that has led some researchers to wonder what the condition’s evolutionary benefits could be.

‘Smart toilet’ monitors for signs of disease

Year 2020 face_with_colon_three

There’s a new disease-detecting technology in the lab of Sanjiv “Sam” Gambhir, MD PhD, and its No. 1 source of data is number one. And number two.

It’s a smart toilet. But not the kind that lifts its own lid in preparation for use; this toilet is fitted with technology that can detect a range of disease markers in stool and urine, including those of some cancers, such as colorectal or urologic cancers. The device could be particularly appealing to individuals who are genetically predisposed to certain conditions, such as irritable bowel syndrome, prostate cancer or kidney failure, and want to keep on top of their health.

“Our concept dates back well over 15 years,” said Gambhir, professor and chair of radiology. “When I’d bring it up, people would sort of laugh because it seemed like an interesting idea, but also a bit odd.” With a pilot study of 21 participants now completed, Gambhir and his team have made their vision of a precision health-focused smart toilet a reality.

Scientists unlock key to reversible, non-hormonal male birth control

The team found that administering an HDAC inhibitor orally effectively halted sperm production and fertility in mice while preserving the sex drive.

Researchers are grappling with the challenge of developing effective male contraceptives as existing attempts to block sperm production, maturation, or fertilization have fallen short, either offering incomplete protection or leading to severe side effects.

Now, a team of researchers at the Salk Institute in the US has developed a novel approach to halting sperm production, which is both non-hormonal and reversible, marking a significant advancement in male contraception research.

Researchers have identified a novel protein complex governing gene expression in sperm production. By administering an existing class of drugs, called HDAC (histone deacetylase) inhibitors to male mice, they effectively disrupt this complex, leading to infertility without impacting libido. This breakthrough suggests a promising avenue for non-hormonal and reversible male contraception, according to the team.

The doctor behind the next big thing in cancer treatment

Finding a cure for cancer is a motivating force for many an aspiring doctor. Few get anywhere close to pursuing that goal. Among them is Dr. Catherine Wu, an oncologist at Boston’s Dana-Farber Cancer Institute, who has had cancer in her sights since second grade, when a teacher asked her and her classmates what they wanted to be when they grew up.

“That’s when there was a lot of coverage on the war on cancer,” she said. “I think I drew a picture of a cloud, probably a rainbow and drew a picture of (me) like, making a cure for cancer or something like that.”

That childhood scribble was prescient. Wu’s research has laid the scientific foundation for the development of cancer vaccines tailored to the genetic makeup of an individual’s tumor. It’s a strategy looking increasingly promising for some hard-to-treat cancers such as melanoma and pancreatic cancer, according to the results of early-stage trials, and may ultimately be widely applicable to many of the 200 or so forms of cancer.