Biology subjects

Uehara, S.

Publications and source records attributed to Uehara, S..

7 recordsLinked to original sources

bioRxiv2026

Precursor of chemically expanded hepatocytes (pre-cHep) with 1-million-fold expansion potential and liver repopulation capacity

Primary human hepatocytes (PHHs) are the gold standard for toxicology and drug metabolism studies in industry. However, their limited availability, substantial batch-to-batch variability, and high cost restrict their use. Here, we report a novel culture condition that reprograms PHHs into a proliferative state. These proliferating cells, termed precursors of chemically expanded hepatocytes (pre-cHep), expand over 106-fold within 30 days while retaining liver repopulation capacity comparable to PHHs. pre-cHep can further differentiate into chemically expanded hepatocytes (cHep) as three-dimensional (3D) spheroids within 7 days in vitro, exhibiting global gene expression profiles, albumin production, and cytochrome P450 (CYP) activities similar to 3D-cultured PHH spheroids (3D PHH). Efficient genetic manipulation of pre-cHep using CRISPR/Cas9 is also achievable. Together, pre-cHep and cHep represent a promising alternative to high-quality PHHs, providing a more affordable, reproducible, and scalable source of human hepatocytes for toxicology, drug metabolism studies, disease modelling, towards precision drug development.

bioengineering↗

bioRxiv2025

Structure-activity relationship of an all-α-helical prenyltransferase reveals a mechanism for indole prenylation.

Enzymes are involved in the biosynthesis of various secondary metabolites found in nature. The catalytic mechanism is regulated by the three-dimensional structure of the enzyme especially at the catalytic site, resulting in the natural products with complicated conformation derived from a regioselective, chemoselective, and stereoselective fashion of the enzyme reaction. Prenyltransferase (PT), which belongs to the prenylsynthase (PS) family, catalyzes the condensation of isoprene to an aromatic compound, consequently producing a terpenoid scaffold structure. Therefore, it plays an important role in which expands the chemical diversity of terpenoids. Although the three-dimensional structures of PS which categorized in the same family were resolved, the catalytic mechanism of the PT has been vailed. In this study, we determined the X-ray crystal structure of a novel prenyltransferase SxPT1 derived from marine Streptomyces. Here we described that SxPT1 analyzed the enzyme reactions and discussed its catalytic mechanism.

biochemistry↗

bioRxiv2025

Discovery of The Clinical Candidate S-892216: A Second-Generation of SARS-CoV-2 3CL Protease Inhibitor for Treating COVID-19

The coronavirus disease 2019 (COVID-19) pandemic crisis has been mitigated by worldwide efforts to develop vaccines and therapeutic drugs. However, there remains concern regarding public health and an unmet need for therapeutic options. Herein, we report the discovery of S-892216, a second-generation SARS-CoV-2 3C-like protease (3CLpro) inhibitor, to treat COVID-19. S-892216 is a reversible covalent 3CLpro inhibitor with highly potent antiviral activity and an EC50 value of 2.48 nM against SARS-CoV-2 infected cells. Structure-based design of a covalent modifier for compound 1 revealed that introducing a nitrile warhead increased 3CLpro inhibition activity by 180-fold. Subsequent optimization efforts yielded S-892216, which combined a favorable pharmacokinetic profile and high off-target selectivity. S-892216 exhibited antiviral activity against diverse SARS-CoV-2 variants, with no cross-resistance to major mutations reducing antiviral activities of nirmatrelvir and ensitrelvir. In SARS-CoV-2-infected mice, S-892216 inhibited viral replication in the lungs similar to ensitrelvir, although at a 30-fold lower dose.

biochemistry↗

bioRxiv2024

Systemic identification of functionally conserved lncRNA metabolic regulators in human and mouse livers

BACKGROUND & AIMSUnlike protein-coding genes, the majority of human long non-coding RNAs (lncRNAs) lack conservation based on their sequences, posing a challenge for investigating their role in a pathophysiological context for clinical translation. This study explores the hypothesis that non-conserved lncRNAs in human and mouse livers may share similar metabolic functions, giving rise to functionally conserved lncRNA metabolic regulators (fcLMRs). METHODSWe developed a sequence-independent strategy to select putative fcLMRs, and performed extensive analysis to determine the functional similarities of putative human and mouse LMR pairs (h/mLMRs). RESULTSWe found that several pairs of putative fcLMRs share similar functions in regulating gene expression. We further demonstrated that a pair of fcLMRs, h/mLMR1, robustly regulated triglyceride levels by modulating the expression of a similar set of lipogenic genes. Mechanistically, h/mLMR1 binds to PABPC1, a regulator of protein translation, via short motifs on either lncRNA with divergent sequences but similar structures. This interaction inhibits protein translation, activating an amino acid-mTOR-SREBP1 axis to regulate lipogenic gene expression. Intriguingly, PABPC1-binding motifs on each lncRNA fully rescued the functions of their corresponding LMRs in the opposite species. Given the elevated expression of h/mLMR1 in humans and mice with hepatic steatosis, the PABPC1-binding motif on hLMR1 emerges as a potential non-conserved human drug target whose functions can be fully validated in a physiologically relevant setting before clinical studies. CONCLUSIONSOur study supports that fcLMRs represent a novel and prevalent biological phenomenon, and deep phenotyping of genetic mLMR mouse models constitutes a powerful approach to understand the pathophysiological role of lncRNAs in the human liver.

physiology↗

bioRxiv2024

Florigen-producing cells express FPF1-LIKE PROTEIN 1 that accelerates flowering and stem growth in long days with sunlight red/far-red ratio in Arabidopsis

Seasonal changes in spring induce flowering by expressing the florigen, FLOWERING LOCUS T (FT), in Arabidopsis. FT is expressed in unique phloem companion cells with unknown characteristics. The question of which genes are co-expressed with FT and whether they have roles in flowering remains elusive. Through tissue-specific translatome analysis, we discovered that under long-day conditions with the natural sunlight red/far-red ratio, the FT-producing cells express a gene encoding FPF1-LIKE PROTEIN 1 (FLP1). The master FT regulator, CONSTANS (CO), controls FLP1 expression, suggesting FLP1s involvement in the photoperiod pathway. FLP1 promotes early flowering independently of FT, is active in the shoot apical meristem, and induces the expression of SEPALLATA 3 (SEP3), a key E-class homeotic gene. Unlike FT, FLP1 facilitates inflorescence stem elongation. Our cumulative evidence indicates that FLP1 may act as a mobile signal. Thus, FLP1 orchestrates floral initiation together with FT and promotes inflorescence stem elongation during reproductive transitions.

plant biology↗

bioRxiv2024

Structural basis for bispecific antibody design: arrangement of domain linkage produces activity enhancement

A bispecific antibody (BsAb) is a protein genetically engineered from two different antibodies, allowing simultaneous binding to two kinds of antigen to bring them into close proximity. BsAbs have been developed as anti-cancer drugs that accumulate lymphocytes onto cancer cells by bridging antigens present on each. Ex3 is a bispecific diabody composed of the two fused variable regions (Fvs) of an anti-epidermal growth factor receptor (EGFR) antibody and an anti-CD3 antibody with potent cancer cytotoxic activity. In Ex3, the LH-type, in which the variable regions of the light chain (VLs) are located at the N-terminus of those of the heavy chain (VHs), exerted 1000-fold greater anticancer activity than the HL-type, in which the VHs are located at the N-terminus of the VLs. This effect (termed activity enhancement), in which the activity is greatly enhanced by domain rearrangement, has been reported not only for Ex3 but also for several other BsAbs. However, the molecular details of this activity enhancement have yet to be elucidated. In this study, we determined the cryo-EM structures of Ex3 LH- and HL-types in complex with CD3 and EGFR. Structural comparison of the LH- and HL-types showed that rearrangement of the domain linkage produces drastic structural differences in the overall shape of these complexes, and dynamics attributed to the flexibility between the two Fvs. These findings provide valuable insights into the molecular mechanism for the activity enhancement of BsAbs. This study will be a stepping stone towards establishing a design foundation for BsAb development.

biochemistry↗

bioRxiv2022

Discovery of S-217622, a Non-Covalent Oral SARS-CoV-2 3CL Protease Inhibitor Clinical Candidate for Treating COVID-19

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in millions of deaths and threatens public health and safety. Despite the rapid global spread of COVID-19 vaccines, effective oral antiviral drugs are urgently needed. Here, we describe the discovery of S-217622, the first oral non-covalent, non-peptidic SARS-CoV-2 3CL protease inhibitor clinical candidate. S-217622 was discovered via virtual screening followed by biological screening of an in-house compound library, and optimization of the hit compound using a structure-based drug-design strategy. S-217622 exhibited antiviral activity in vitro against current outbreaking SARS-CoV-2 variants and showed favorable pharmacokinetic profiles in vivo for once-daily oral dosing. Furthermore, S-217622 dose-dependently inhibited intrapulmonary replication of SARS-CoV-2 in mice, indicating that this novel non-covalent inhibitor could be a potential oral agent for treating COVID-19.

biochemistry↗