Biology subjects

Ho, P. L.

Publications and source records attributed to Ho, P. L..

4 recordsLinked to original sources

bioRxiv2023

A Sweeter Future: Using protein language models for exploring sweeter brazzein homologs

Reducing sugar intake lowers the risk of obesity and associated metabolic disorders. Currently, this is achieved using artificial non-nutritive sweeteners, where their safety is widely debated and their contributions in various diseases is controversial. Emerging research suggests that these sweeteners may even increase the risk of cancer and cardiovascular problems, and some people experience gastrointestinal issues as a result of using them. A safer alternative to artificial sweeteners could be sweet-tasting proteins, such as brazzein, which do not appear to have any adverse health effects. In this study, protein language models were explored as a new method for protein design of brazzein. This innovative approach resulted in the identification of unexpected mutations, which opened up new possibilities for engineering thermostable and potentially sweeter versions of brazzein. To facilitate the characterization of the brazzein mutants, a simplified procedure was developed for expressing and analyzing related proteins. This process involved an efficient purification method using Lactococcus lactis (L. lactis), a generally recognized as safe (GRAS) bacterium, as well as taste receptor assays to evaluate sweetness. The study successfully demonstrated the potential of computational design in producing a more heat-resistant and potentially more palatable brazzein variant, V23.

synthetic biology↗

bioRxiv2023

Development and characterization of a multimeric recombinant protein based on the spike protein receptor binding domain of SARS-CoV-2 that can neutralize virus infection

BackgroundThe SARS-CoV-2 virus, responsible for the COVID-19 pandemic, has four structural proteins and sixteen non-structural proteins. The S-protein is one of the structural proteins exposed on the surface of the virus and is the main target for producing neutralizing antibodies and vaccines. The S-protein forms a trimer that can bind the angiotensin-converting enzyme 2 (ACE2) through its receptor binding domain (RBD) for cell entry. MethodsWe stably expressed in a constitutive manner in HEK293 cells a new recombinant protein containing a signal sequence of immunoglobulin to produce an extended C-terminal portion of the RBD followed by a region responsible for the trimerization inducer of the bacteriophage T4, and a sequence of 6 histidines. The protein was produced and released in the culture supernatant of cells and was purified by Ni-agarose column and exclusion chromatography. It was then characterized by SDS-polyacrylamide gel and used as antigen to generate protective antibodies to inhibit ACE2 receptor interaction and virus entry into Vero cells. ResultsThe purified protein displayed a molecular mass of 135 kDa and with a secondary structure like the monomeric RBD. Electrophoresis analysis in SDS-polyacrylamide gel with and without reducing agents, and in the presence of crosslinkers indicated that it forms a multimeric structure composed of trimers and hexamers. The purified protein was able to bind the ACE2 receptor and generated high antibody titers in mice (1:10000), capable of inhibiting the binding of biotin labeled ACE2 to the virus S1 subunit, and to neutralize the entry of the SARS-CoV-2 Wuhan strain into cells. ConclusionOur results characterize a new multimeric protein based on S1 subunit to combat COVID-19, as a possible immunogen or antigen for diagnosis.

microbiology↗

bioRxiv2019

The potential role of collagens in congenital Zika syndrome: A systems biology approach

Zika virus (ZIKV) infection during pregnancy could cause a set of severe abnormalities in the fetus known as congenital Zika syndrome (CZS). Experiments using animal models and in vitro systems significantly contributed to our understanding of the physiopathology of ZIKV infection. However, the molecular basis of CZS is not yet studied in humans. Here, we used a systems biology approach to integrate transcriptomic, proteomic and genomic data from post-mortem brains of neonates with CZS. We observed that collagen genes were greatly reduced in CZS brains at both the RNA and protein levels and that neonates with CZS have several polymorphisms in collagen genes associated with osteogenesis imperfect and arthrogryposis. These findings were validated using immunohistochemistry and collagen staining of ZIKV infected and non-infected samples. Additionally, it was found that cell adhesion genes that are essential for neurite outgrowth and axon guidance were up-regulated and thereby confirmed the neuronal migration defects observed. This work provided new insights into the underlying mechanisms of CZS and revealed host genes associated with CZS susceptibility.

systems biology↗

bioRxiv2019

Systems Analysis of Subjects Acutely Infected with Chikungunya Virus

The largest ever recorded epidemic of the chikungunya virus (CHIKV) began in 2004 and affected four continents. Acute symptomatic infections are typically associated with the onset of fever and often debilitating polyarthralgia/polyarthritis. In this study, a systems biology approach was used to analyze the blood transcriptomes of adults acutely infected with CHIKV. Gene signatures that were associated with viral RNA amounts and to the onset of symptoms were identified. Among those genes, the putative role of Eukaryotic Initiation Factor (eIF) family genes and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC3A) in the CHIKV replication process were displayed. We further compared these signatures with those induced by dengue virus infection and rheumatoid arthritis. Finally, we demonstrated that CHIKV infection in mice induced IL-1 beta production in a mechanism highly dependent on the inflammasome NLRP3 activation. The findings provided valuable insights into the virus-host interactions during the acute phase and could be useful in the investigation of new and effective therapeutic interventions.

immunology↗