The Department of Bioengineering at the Indian Institute of Science (IISc) has made significant strides in tuberculosis (TB) research with the development of a novel 3D hydrogel culture system designed to mimic the complex environment of the mammalian lung. This innovative platform represents a substantial advancement over traditional 2D culture models, offering enhanced capabilities for studying TB infection mechanisms and testing the efficacy of therapeutic interventions.
The TB-causing agent, Mycobacterium tuberculosis (Mtb), continues to be a serious global health concern, killing millions of people each year. The 2D monolayer systems utilized in conventional culture models to research tuberculosis infection are unable to accurately recreate the complex 3D microenvironment present in lung tissues. Extracellular matrix (ECM) physiological significance and lung tissue softness—two important parameters regulating cell activity and pathogen interaction—are absent from these models.
The IISc research team, under the direction of Rachit Agarwal, used collagen, an essential ECM component of lung cells, to create a 3D hydrogel growth system. When pH is raised, collagen, which is soluble in water at a slightly acidic pH, forms fibrils and cross-links to produce a structure resembling gel. This hydrogel matrix incorporates Mtb bacteria and human macrophages, which are immune cells important for tuberculosis defense. This creates an environment that is ideal for long-term studies of infection dynamics.
Traditional 2D models have various drawbacks that are addressed by the 3D hydrogel culture technique. The collagen-based hydrogel more closely resembles the softness and architecture of lung extracellular matrix (ECM) than rigid, monolayer culture plates, which do a poor job of simulating lung tissue conditions. In addition to maintaining mammalian cell viability for up to three weeks—a notable improvement over the 4–7 days in 2D cultures—this environment also more closely resembles the gene expression profiles of real human lung samples.
The researchers used RNA sequencing to find patterns of gene expression in the lung cells inside the hydrogel, which provided information about how these cells react to tuberculosis infection. Crucially, the research also showed that the important TB medication pyrazinamide was effective in the 3D hydrogel at clinically meaningful dosages. The system’s superior capacity to replicate clinical circumstances and medication reactions is highlighted by previous studies’ inability to replicate therapeutic efficacy at comparable doses in conventional models.
In order to study the variables impacting the progression of latent TB as opposed to active disease, the team intends to improve the hydrogel system even more. Granulomas are clusters of infected immune cells that are observed in TB patients. Gaining insight into these pathways may help in the discovery of novel pharmacological targets and more potent anti-TB treatments.
The potential applications of the 3D hydrogel culture extend beyond TB research. The system’s scalability and simplicity make it suitable for industrial scale-up, offering pharmaceutical companies a robust platform for drug testing and discovery. The filed Indian patent underscores its potential for widespread adoption and impact in advancing TB treatment strategies globally.
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