Research Areas
Our research aims to deepen the understanding of placental biology by identifying genes essential for normal development and examining the impact of placental abnormalities on maternal health and fetal outcomes. Additionally, we seek to establish connections between changes in structural, functional, and molecular profiles during the cardiovascular transition at birth and the manifestation of congenital heart diseases in mouse models. Utilizing advanced imaging technologies and innovative methodologies, our goal is to pave the way for groundbreaking discoveries in developmental biology, disease progression, and regenerative medicine.
Knockout Mouse Phenotyping Program (KOMP2)
Our laboratory has harnessed and optimized the application of contrast enhanced micro-CT to support numerous projects, either through collaborative efforts or provided as services at the Optical Imaging and Vital Microscopy Core at Baylor College of Medicine. Specifically, we have streamlined the utilization of iodine-contrast micro-CT to conduct comprehensive 3D morphological and anatomical analyses of mouse embryo and neonate development. In support of the NIH-funded Knockout Mouse Project (KOMP), we have imaged and phenotyped over 4,500 mouse embryos across 316 single gene knockout embryonic lethal/perinatal lethal and sub-viable mouse strains, while extending this technology to study mouse development from embryonic to early postnatal stages. We have also extended our techniques to study mouse embryos at early post-implantation stages (P8.0 to P9.5) within extra-embryonic tissues, such as the yolk sac or the decidua, without causing physical disruption to the embryos. This method enables a full, undisturbed analysis of embryo turning, allantois development, vitelline vessels remodeling, yolk sac and early placenta development, which provides increased insights into early embryonic lethality in mutant lines. Moreover, these methods are inexpensive, simple to learn and do not require substantial processing time, making them ideal for high-throughput analysis of mouse mutants with embryonic and early postnatal lethality. Our expertise isn't limited to specific developmental stages or mouse models; we have also applied these methods to further investigate mouse organ systems and other animal models, such as bat and Delphinapterus leucas embryos. These experience and expertise are setting the sound foundation for my research program to advance the field and broaden the applicability of micro-CT by developing immunolabeling-driven contrast enhancement in X-ray based detection technology.
Tissue clearing and whole mount fluorescence imaging
In my laboratory, we have established routine workflows to perform mouse whole organ clearing with a commercially available aqueous-based tissue clearing system X-CLARITY (Logos Biosystems), as well as with different organic solvent-based clearing techniques (BABB/3DISCO/iDISCO) on different mouse organs for imaging on confocal,lightsheet, and optical projection tomography. We have also developed a new aqueous based clearing method, named EZ Clear, which uses water-miscible tetrahydrofuran (THF, 50% (v/v) in ddH2O) for lipid removal followed by rendering the tissue transparent in aqueous RI-matching solution. This robust protocol can effectively clear adult mouse organs in 48 hours with 3 simple steps while keeping the sample fully hydrated. It can also reach high tissue transparency comparable to solvent-based method, such as 3DISCO, with minimal changes in tissue size. In addition, we have also demonstrated that sample processed with EZ Clear is compatible with immunofluorescence staining. This discovery provides support for testing the feasibility of identifying specific cell populations based on surface and intracellular antigens by fluorescence-activated cell sorting (FACS) after clearing. Our current progress and expertise well position us to advance the optimization of clearing procedures for various animal models and human tissues. These advancements will maintain sample hydration, ensure compatibility with tissue dissociation and cell recovery, and preserve genetic information for single cell and spatial omics studies.
In depth phenotyping across fetal-placental-maternal axis
Being an essential organ during pregnancy, the placenta is acting as the interface between the mother and fetus, facilitating the transfer of nutrients and oxygen, waste elimination, hormone secretion, and immune protection. Despite its vital role in reproductive outcomes and lifelong health, the placenta's involvement and its impact on maternal physiology during pregnancy are often overlooked when studying fetal congenital phenotypes. Dysfunctions in placental development are known to result in severe obstetric complications, such as intrauterine growth restriction, miscarriage, stillbirth, and various maternal disorders during pregnancy. This project aims to delve into the intricate relationship between embryonic lethality, placental development, and maternal health. Leveraging the embryonic and perinatal lethal mouse strains generated by the Knockout Mouse Project at Baylor College of Medicine (BCM-KOMP2), we aim to investigate genes essential for normal placental development and the repercussions of embryonic/perinatal lethality on maternal physiology. The objectives of this project are (1) phenotypic analysis of placental anatomy: by using iodine-contrasted microCT imaging, we will assess the placentas of the embryonic and perinatal lethal strains at different stages of gestation to measure various anatomical features and compare these to normal controls. (2) Assessment of maternal and fetal vasculature development independently in the placenta: at the last viable stage of the homozygous embryonic/perinatal lethal embryos of each strain, we will analyze the placental vasculature using tissue clearing and wholemount fluorescence imaging to quantitatively assess the maternal and fetal vasculature development in the placenta. (3) Impact on maternal health: we will assess the short- and long-term impacts of embryonic and perinatal lethality on the heterozygous dams by monitoring the cardiovascular function during pregnancy and postpartum using echocardiography and electrocardiography. The outcomes of this research could significantly influence the early detection and prevention of pregnancy complications by shedding light on the molecular and physiological pathways involved in placental development and function. This comprehensive approach will not only help in identifying the genetic underpinnings of placental dysfunction but also enhance our understanding of their broader impacts on pregnancy and maternal health.
The structural, functional, and molecular correlation of congenital heart diseases
The cardiovascular transition at birth is crucial for the neonate's survival. Upon separation from placental circulation, the neonatal cardiovascular system must assume full responsibility, undergoing significant anatomical, physiological, and biochemical changes. Key examples include the closure of the foramen ovale (a connection between the left and right atria) and the ductus arteriosus following the establishment of pulmonary and systemic circulation. Although some prenatal cardiovascular phenotypes, such as a dilated left ventricle, ventricular septal defect, and ventricular hypertrophy, have been identified, the impact of these phenotypes on heart physiology at birth and their role in anatomical remodeling remains underexplored. Additionally, there are gaps in understanding the timeline of anatomical changes, the physiological shifts that trigger these changes, and the associated transcriptomic alterations during this transition.
A deeper understanding of the interplay between anatomical and physiological changes during the cardiovascular transition at birth could lead to better detection and prevention strategies for congenital heart disease. Our research aims to elucidate how congenital heart defects affect heart development during this critical transition. The findings from these studies are expected to provide new insights into how impaired heart structure and function during the neonatal transition contribute to congenital heart disease and how early detection and intervention could improve patient outcomes.