Organoids: A New Model for SARS-CoV-2 Translational Research

Biophysical Analysis of Potential Inhibitors of SARS-CoV-2 Cell Recognition and Their Effect on Viral Dynamics in Different Cell Types: A Computational Prediction from In Vitro Experimental Data

Recent reports have suggested that the susceptibility of cells to SARS-CoV-2 infection can be influenced by various proteins that potentially act as receptors for the virus. To investigate this further, we conducted simulations of viral dynamics using different cellular systems (Vero E6, HeLa, HEK293, and CaLu3) in the presence and absence of drugs (anthelmintic, ARBs, anticoagulant, serine protease inhibitor, antimalarials, and NSAID) that have been shown to impact cellular recognition by the spike protein based on experimental data. Our simulations revealed that the susceptibility of the simulated cell systems to SARS-CoV-2 infection was similar across all tested systems. Notably, CaLu3 cells exhibited the highest susceptibility to SARS-CoV-2 infection, potentially due to the presence of receptors other than ACE2, which may account for a significant portion of the observed susceptibility. Throughout the study, all tested compounds showed thermodynamically favorable and stable binding to the spike protein. Among the tested compounds, the anticoagulant nafamostat demonstrated the most favorable characteristics in terms of thermodynamics, kinetics, theoretical antiviral activity, and potential safety (toxicity) in relation to SARS-CoV-2 spike protein-mediated infections in the tested cell lines. This study provides mathematical and bioinformatic models that can aid in the identification of optimal cell lines for compound evaluation and detection, particularly in studies focused on repurposed drugs and their mechanisms of action. It is important to note that these observations should be experimentally validated, and this research is expected to inspire future quantitative experiments.

Advances in biomaterial-based cardiac organoids

Cardiovascular disease (CVD) is one of the important causes of death worldwide. The incidence and mortality rates are increasing annually with the intensification of social aging. The efficacy of drug therapy is limited in individuals suffering from severe heart failure due to the inability of myocardial cells to undergo regeneration and the challenging nature of cardiac tissue repair following injury. Consequently, surgical transplantation stands as the most efficient approach for treatment. Nevertheless, the shortage of donors and the considerable number of heart failure patients worldwide, estimated at 26 million, results in an alarming treatment deficit, with only around 5000 heart transplants feasible annually. The existing major alternatives, such as mechanical or xenogeneic hearts, have significant flaws, such as high cost and rejection, and are challenging to implement for large-scale, long-term use. An organoid is a three-dimensional (3D) cell tissue that mimics the characteristics of an organ. The critical application has been rated in annual biotechnology by authoritative journals, such as Science and Cell. Related industries have achieved rapid growth in recent years. Based on this technology, cardiac organoids are expected to pave the way for viable heart repair and treatment and play an essential role in pathological research, drug screening, and other areas. This review centers on the examination of biomaterials employed in cardiac repair, strategies employed for the reconstruction of cardiac structure and function, clinical investigations pertaining to cardiac repair, and the prospective applications of cardiac organoids. From basic research to clinical practice, the current status, latest progress, challenges, and prospects of biomaterial-based cardiac repair are summarized and discussed, providing a reference for future exploration and development of cardiac regeneration strategies.

In vitro high-content tissue models to address precision medicine challenges

The field of precision medicine allows for tailor-made treatments specific to a patient and thereby improve the efficiency and accuracy of disease prevention, diagnosis, and treatment and at the same time would reduce the cost, redundant treatment, and side effects of current treatments. Here, the combination of organ-on-a-chip and bioprinting into engineering high-content in vitro tissue models is envisioned to address some precision medicine challenges. This strategy could be employed to tackle the current coronavirus disease 2019 (COVID-19), which has made a significant impact and paradigm shift in our society. Nevertheless, despite that vaccines against COVID-19 have been successfully developed and vaccination programs are already being deployed worldwide, it will likely require some time before it is available to everyone. Furthermore, there are still some uncertainties and lack of a full understanding of the virus as demonstrated in the high number new mutations arising worldwide and reinfections of already vaccinated individuals. To this end, efficient diagnostic tools and treatments are still urgently needed. In this context, the convergence of bioprinting and organ-on-a-chip technologies, either used alone or in combination, could possibly function as a prominent tool in addressing the current pandemic. This could enable facile advances of important tools, diagnostics, and better physiologically representative in vitro models specific to individuals allowing for faster and more accurate screening of therapeutics evaluating their efficacy and toxicity. This review will cover such technological advances and highlight what is needed for the field to mature for tackling the various needs for current and future pandemics as well as their relevancy towards precision medicine.

Application of microfluidic technologies on COVID-19 diagnosis and drug discovery

The ongoing coronavirus disease 2019 (COVID-19) pandemic has boosted the development of antiviral research. Microfluidic technologies offer powerful platforms for diagnosis and drug discovery for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) diagnosis and drug discovery. In this review, we introduce the structure of SARS-CoV-2 and the basic knowledge of microfluidic design. We discuss the application of microfluidic devices in SARS-CoV-2 diagnosis based on detecting viral nucleic acid, antibodies, and antigens. We highlight the contribution of lab-on-a-chip to manufacturing point-of-care equipment of accurate, sensitive, low-cost, and user-friendly virus-detection devices. We then investigate the efforts in organ-on-a-chip and lipid nanoparticles (LNPs) synthesizing chips in antiviral drug screening and mRNA vaccine preparation. Microfluidic technologies contribute to the ongoing SARS-CoV-2 research efforts and provide tools for future viral outbreaks.

Recent Advances in Brain Organoid Technology for Human Brain Research

Brain organoids are self-assembled three-dimensional aggregates with brain-like cell types and structures and have emerged as new model systems that can be used to investigate human neurodevelopment and neurological disorders. However, brain organoids are not as mature and functional as real human brains due to limitations of the culture system with insufficient developmental patterning signals and a lack of components that are important for brain development and function, such as the non-neural population and vasculature. In addition, establishing the desired brain-like environment and monitoring the complex neural networks and physiological functions of the brain organoids remain challenging. The current protocols to generate brain organoids also have problems with heterogeneity and batch variation due to spontaneous self-organization of brain organoids into complex architectures of the brain. To address these limitations of current brain organoid technologies, various engineering platforms, such as extracellular matrices, fluidic devices, three-dimensional bioprinting, bioreactors, polymeric scaffolds, microelectrodes, and biochemical sensors, have been employed to improve neuronal development and maturation, reduce structural heterogeneity, and facilitate functional analysis and monitoring. In this review, we provide an overview of the latest engineering techniques that overcome these limitations in the production and application of brain organoids.

Cell and Animal Models for SARS-CoV-2 Research

During the last two years following the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, development of potent antiviral drugs and vaccines has been a global health priority. In this context, the understanding of virus pathophysiology, the identification of associated therapeutic targets, and the screening of potential effective compounds have been indispensable advancements. It was therefore of primary importance to develop experimental models that recapitulate the aspects of the human disease in the best way possible. This article reviews the information concerning available SARS-CoV-2 preclinical models during that time, including cell-based approaches and animal models. We discuss their evolution, their advantages, and drawbacks, as well as their relevance to drug effectiveness evaluation.

Organoid and microfluidics-based platforms for drug screening in COVID-19

Proposing efficient prophylactic and therapeutic strategies for coronavirus 2019 (COVID-19) requires precise knowledge of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogenesis. An array of platforms, including organoids and microfluidic devices, have provided a basis for studies of SARS-CoV-2. Here, we summarize available models as well as novel drug screening approaches, from simple to more advanced platforms. Notably, organoids and microfluidic devices offer promising perspectives for the clinical translation of basic science, such as screening therapeutics candidates. Overall, modifying these advanced micro and macro 3D platforms for disease modeling and combining them with recent advances in drug screening has significant potential for the discovery of novel potent drugs against COVID-19.

An Adverse Outcomes Approach to Study the Effects of SARS-CoV-2 in 3D Organoid Models

The novel SARS-CoV-2 virus outbreak is the major cause of a respiratory disease known as COVID-19. It has caused a global pandemic and has resulted in mortality in millions. The primary mode of infection is respiratory ailments, however, due to multi-organ complications, COVID-19 patients displays a greater mortality numbers. Due to the 3Rs Principle (Refine, Reduce, Replacement), the scientific community has shifted its focus to 3D organoid models rather than testing animal models. 3D organoid models provide a better physiological architecture as it mimics the real tissue microenvironment and is the best platform to recapitulate organs in a dish. Hence, the organoid approach provides a more realistic drug response in comparison to the traditional 2D cellular models, which lack key physiological relevance due to the absence of proper surface topography and cellular interactions. Furthermore, an adverse outcome pathway (AOPs) provides a best fit model to identify various molecular and cellular events during the exposure of SARS-CoV-2. Hence, 3D organoid research provides information related to gene expression, cell behavior, antiviral studies and ACE2 expression in various organs. In this review, we discuss state-of-the-art lung, liver and kidney 3D organoid system utilizing the AOPs to study SARS-CoV-2 molecular pathogenesis. Furthermore, current challenges are discussed for future application of 3D organoid systems for various disease states.

Recent Advances of COVID-19 Modeling Based on Regenerative Medicine

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has caused a pandemic since December 2019 that originated in Wuhan, China. Soon after that, the world health organization declared Coronavirus disease-2019 a global health concern. SARS-CoV-2 is responsible for a lethal respiratory infection as well as the involvement of other organs due to its large tropism spectrum such as neurologic, cardiovascular, endocrine, gastrointestinal, and renal systems. Since the behavior of the virus is not fully understood, a new manifestation of the infection is revealed every day. In order to be able to design more efficient drugs and vaccines to treat the infection, finding out the exact mechanism of pathogenicity would be necessary. Although there have been some big steps toward understanding the relevant process, there are still some deficiencies in this field. Accordingly, regenerative medicine (RM), can offer promising opportunities in discovering the exact mechanisms and specific treatments. For instance, since it is not always possible to catch the pathophysiology mechanisms in human beings, several modeling methods have been introduced in this field that can be studied in three main groups: stem cell-based models, organoids, and animal models. Regarding stem cell-based models, induced pluripotent stem cells are the major study subjects, which are generated by reprogramming the somatic stem cells and then directing them into different adult cell populations to study their behavior toward the infection. In organoid models, different cell lines can be guided to produce a 3D structure including liver, heart, and brain-like platforms. Among animal models, mice are the most common species in this field. However, in order for mice models to be permissive to the virus, angiotensin-converting enzyme 2 receptors, the main receptor involved in the pathogenicity of the virus, should be introduced to the host cells through different methods. Here, the current known mechanism of SARS-CoV-2 infection, different suggested models, the specific response toward different manipulation as well as challenges and shortcomings in each case have been reviewed. Finally, we have tried to provide a quick summary of the present available RM-based models for SARS-CoV-2 infection, as an essential part of developing drugs, for future therapeutic goals.

In Vitro Strategies to Vascularize 3D Physiologically Relevant Models

Vascularization of 3D models represents a major challenge of tissue engineering and a key prerequisite for their clinical and industrial application. The use of prevascularized models built from dedicated materials could solve some of the actual limitations, such as suboptimal integration of the bioconstructs within the host tissue, and would provide more in vivo-like perfusable tissue and organ-specific platforms. In the last decade, the fabrication of vascularized physiologically relevant 3D constructs has been attempted by numerous tissue engineering strategies, which are classified here in microfluidic technology, 3D coculture models, namely, spheroids and organoids, and biofabrication. In this review, the recent advancements in prevascularization techniques and the increasing use of natural and synthetic materials to build physiological organ-specific models are discussed. Current drawbacks of each technology, future perspectives, and translation of vascularized tissue constructs toward clinics, pharmaceutical field, and industry are also presented. By combining complementary strategies, these models are envisioned to be successfully used for regenerative medicine and drug development in a near future.

Application of Human Induced Pluripotent Stem Cell-Derived Cellular and Organoid Models for COVID-19 Research

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its rapid international spread has caused the coronavirus disease 2019 (COVID-19) pandemics, which is a global public health crisis. Thus, there is an urgent need to establish biological models to study the pathology of SARS-CoV-2 infection, which not only involves respiratory failure, but also includes dysregulation of other organs and systems, including the brain, heart, liver, intestines, pancreas, kidneys, eyes, and so on. Cellular and organoid models derived from human induced pluripotent stem cells (iPSCs) are ideal tools for in vitro simulation of viral life cycles and drug screening to prevent the reemergence of coronavirus. These iPSC-derived models could recapitulate the functions and physiology of various human cell types and assemble the complex microenvironments similar with those in the human organs; therefore, they can improve the study efficiency of viral infection mechanisms, mimic the natural host-virus interaction, and be suited for long-term experiments. In this review, we focus on the application of in vitro iPSC-derived cellular and organoid models in COVID-19 studies.