Silencing the Immunogenicity of AAV Vectors 

Recombinant adeno-associated viral (AAV) vectors are an appealing delivery strategy for in vivo gene therapy but face a formidable challenge: avoiding detection by an ever-watchful immune system (1,2). Efforts to compensate for the immune response to these virus particles have included immunosuppressive drugs and engineering the AAV vector to be especially potent to minimize its effective dosage. These methods, however, come with their own challenges and do not directly solve for the propensity of AAV vectors to induce immune responses.  

A recent study introduced a new approach to reduce the inherent immunogenicity of AAV vectors (2). Researchers strategically swapped out amino acids in the AAV capsid to remove the specific sequences recognized by T-cells that elicit the most pronounced immune response. As a result, they significantly reduced T-cell mediated immunogenicity and toxicity of the AAV vector without compromising its performance.  

Read on to get more of the study details, which include the use of NanoLuc® luciferase and Nano-Glo® Fluorofurimazine In Vivo Substrate for in vivo bioluminescent imaging of the AAV variants’ distribution and transduction efficiency in mice. 

A teal colored ribbon model of a AAV virus capsid floats against a black background.
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Discovery of Protein Involved in TDP-43 Cytoplasmic Re-Localization Points to Potential Gene Therapy for ALS and FTD

A mouse stands on test tubes next to graphic of DNA double helix.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal and rapidly progress as neurodegenerative diseases. While inherited mutations can cause both conditions, they mostly appear sporadically in individuals without a known family history. Despite affecting different neurons, both diseases share a common hallmark: the pathogenic buildup of abnormal nuclear TAR-binding protein 43 (TDP-43) in the cytoplasm of affected motor neuron cells. Current theories propose that this cytoplasmic re-localization triggers toxic phosphorylation and fragmentation of TDP-43. Concurrently, a decrease of TDP-43 in the nucleus diminishes TDP-43-related physiological nuclear functions, contributing to the diseases’ progression (1).

Although this cytoplasmic accumulation of TDP-43 plays a significant role in the pathogenesis of ALS and FTD, the cellular mechanisms involved in the re-localization of TDP-43 to the cytoplasm is not known (2). A team of Australian neuroscientists led by Dr. Lars Ittner believe that they have found part of the answer for sporadic forms of the diseases. They identified novel interactions between pathogenic or dysfunctional forms of TDP-43 and the 14.3.3ɵ isoform of the cytoplasmic protein 14-3-3. By targeting this interaction with an AAV-based gene therapy vector, they were able to block and even partially reverse neurodegeneration in ALS/FTD mouse models.  

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Addressing the Problem of Dosing in Gene Therapy

One key obstacle to crafting effective gene therapies is the ability to tailor dosing according to a patient’s needs. This can be tricky because even if protein production is successful, staying within the therapeutic window is paramount—too much of a protein could be toxic, and too little will not produce the desired effect. This balance is difficult to achieve with current technologies. In a study recently published in Nature Biotechnology, researchers at Baylor College of Medicine investigated a possible solution to this problem, engineering a molecular “on/off” switch that could regulate gene expression and maintain protein production at dose-dependent, therapeutic levels.

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Transformative Gene Therapies Greenlit for Sickle Cell Disease

In sickle cell anemia, red bloods cells elongate into an abnormal “sickled” shape

Sickle cell disease is a debilitating blood disorder that causes recurrent pain crises and severe health effects, and can drastically impact quality of life. Recently, Vertex Pharmaceuticals and CRISPR Therapeutics introduced Casgevy, or exa-cel, a novel form of gene therapy that could radically change the management of sickle cell disease. On the heels of exa-cel’s approval in Britain, this groundbreaking therapy was also recently approved in the U.S.

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How Does Ozempic Work? The Mechanism of Action of Semaglutide and Other GLP-1 Receptor Agonists

In early 2023, a type 2 diabetes medication, semaglutide (brand names Ozempic, Rybelsus), drew huge amounts of attention on social media and in popular culture. The reason? People were getting off-label (that is, not for treating type 2 diabetes) prescriptions of Ozempic to take advantage of one of its common side effects—measurable weight loss.

How does semaglutide and other drugs of its type manage diabetes on a molecular level, and what drives the weight loss effects?

Female leg stepping onto a weigh scale
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Small Molecule Therapies and Immunotherapies: An Introduction to Targeted Cancer Treatments

Cancer is a deceptively singular term for hundreds of different diseases. These diseases can affect almost any part of the body.  In the United States, cancer is the second most common cause of death (1). At its most basic level, however, cancer is the abnormal and uncontrolled division of cells resulting from genetic changes in one or more cells.

This prolific cell division is what many standard chemotherapies act upon. These therapies are developed to kill rapidly dividing cells but often don’t discriminate between normal and cancerous cells. In contrast, targeted therapies are designed to interact with (or target) specific pathways, processes or proteins whose abnormal behavior is associated with cancer development and growth. Targeting these abnormal cellular functions can counteract cancer in different ways. They can interfere with tumor growth, carry other drugs into tumor cells or help the immune system find and kill cancerous cells. Targeted therapies can be loosely divided into two categories: small molecule therapies and immunotherapies.

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