PubMed Health⌕ Search

Biomedical subjects

Fei Tang

Publications and source records attributed to Fei Tang.

7 recordsLinked to original sources
PubMed2026

Multicellular ecosystems: Linking cellular diversity to tissue function and disease.

Tissue function emerges from coordinated interactions among diverse cell populations, whereas disruption of these interactions can lead to dysfunction. Recent advances in single-cell and spatial genomics have not only cataloged cellular diversity but also revealed how tissues are organized as dynamic multicellular ecosystems. Moving beyond descriptive cell atlases toward functional, system-level representations represents a major frontier in tissue biology. In this review, we outline conceptual and methodological frameworks for dissecting multicellular coordination, highlight recurrent multicellular ecosystems across physiological and pathological contexts, and explore translational opportunities such as patient stratification, therapeutic reprogramming, and regenerative strategies. Viewing tissues through an ecosystem lens provides a unifying framework that links cellular diversity to emergent tissue function and informs strategies for disease intervention.

Humans↗
PubMed2006

Determination of octopamine, synephrine and tyramine in Citrus herbs by ionic liquid improved 'green' chromatography.

Without adding any volatile organic solvents, aqueous solutions of room temperature ionic liquids (RTILs) were used as 'green' mobile phases to determine octopamine, synephrine and tyramine by liquid chromatography. The problems of the adrenergic amines separation, such as band tailing, low retention and low resolution were solved successfully by using RTIL. The effect of 1-ethyl-3-methylimidazolium tertafluoroborate ([EMIM][BF4]) was the best in the six investigated RTILs. The concentration of [EMIM][BF4], mobile phase pH and column temperature, which influenced the chromatographic behaviors of the analytes, were investigated in detail. The change of retention factors caused by pH shift was obviously suppressed by [EMIM][BF4]. The sensitivity, accuracy and repeatability of this method were found to be satisfactory. The contents of adrenergic amines in several Citrus herbs and extracts, such as Fructus aurantii immaturus, were simultaneously determined by this 'green' chromatographic method.

Adrenergic alpha-Agonists↗
PubMed2004

Ultrasensitive detection of protein using an aptamer-based exonuclease protection assay.

Currently, methods for protein detection are not as sensitive and specific as methods for detection of specific nucleic acid sequences. Here, we present an analogous technique for detection of proteins using aptamers as ligands for target binding. We have named this method the aptamer-based exonuclease protection assay. We applied a special oligonucleotide probe containing a thrombin aptamer, which has the capacity to recognize thrombin with high affinity and specificity. The aptamer probe is a 22-base-long single-strand oligonucleotide with the thrombin aptamer sequence at the 3'-terminus and 7 additional nucleotides at the 5'-terminus, which is able to bind thrombin with high affinity and specificity. In the exonuclease protection assay, thrombin binds the aptamer and thereby protects it from degradation by exonuclease I, whereas any unbound aptamer probe is degraded by exonuclease I. Subsequently, the aptamer probes that were protected from exonuclease I by thrombin act as linkers to join two free connectors, which contain sequences matching the probe. The joined products, which reflect the identity and amount of the target protein, are amplified by PCR. The exonuclease protection assay is extremely sensitive, since it is based on PCR amplification. This method can detect as few as several hundred molecules of target protein without using washes or separations. In addition, this new method for protein detection is simple and inherits all the advantages of aptamers. The mechanism, moreover, may be generalized and used for other forms of protein analysis.

Aptamers, Nucleotide↗
PubMed2003

An initiator and its flanking elements function as a core promoter driving transcription of the Hepatopoietin gene.

Hepatopoietin (HPO)/ALR (augmenter of liver regeneration), as a versatile hepatotrophic growth factor and a cellular thiol oxidase, is involved in a wide variety of basic processes of various tissues, especially in liver and testis. Here, we studied the regulation of HPO gene expression. By sequential deletion of the HPO 5'-flanking region, the minimal promoter of the HPO gene was shown to span positions -22 to +42 relative to the transcriptional start point. Further transfection assay and mutation analysis showed that the core promoter contains a functional initiator. Interestingly, three tandem repeats of a CTGGAGGC element, surrounding the transcription start site and bound by specific nuclear factors, were found to be pivotal for the promoter activity. This initiator flanking element functions in an initiator-dependent fashion and is present in many initiator-containing genes. Taken together, our findings revealed that the initiator-like element and its flanking repeat sequence comprise a core promoter and drive the transcriptional initiation of the HPO gene in a combinatorial manner. The HPO gene promoter might represent a novel architecture for core promoters.

Base Sequence↗
PubMed2002

Identification, characterization, and functional study of the two novel human members of the semaphorin gene family.

We cloned two novel human transmembrane semaphorins, (HSA)SEMA6C and (HSA)SEMA6D, that belong to the class VI subgroup of the semaphorin family. The genes for SEMA6C and SEMA6D are mapped on chromosome 1q12-21.1 and 15q21.1, respectively. Among the adult tissues, SEMA6C is expressed only in skeletal muscle, whereas SEMA6D is expressed abundantly in kidney, brain, and placenta and moderately in the heart and skeletal muscles. During murine development, neither SEMA6C nor SEMA6D was expressed in embryonic day 10.5 (E10.5) embryos, but both were highly expressed in the areas of the lateral ventricle, the striatum, the wall of the midbrain, the pons/midbrain junction, and the choroid plexus of E13 embryos. Were neurons, neither axons nor astrocytes, highly expressed both semaphorins. Three isoforms of SEMA6C and five isoforms of SEMA6D derived from alternative splicing were identified, and their expression was regulated in a tissue- and development-dependent manner. Deletion analysis indicated that a sema domain and a PSI domain are integrally necessary for correct post-translation modification and subcellular localization. The extracellular domain of SEMA6C inhibited axonal extension of nerve growth factor-differentiated PC12 cells and induced the growth cone collapse of chicken dorsal root ganglion, rat hippocampal neurons, and rat cortical neurons in a dose-responsive manner. SEMA6D acted like SEMA6C except it had no significant effect on the growth cones of rat cortical neurons.

Alternative Splicing↗
PubMed2001

Intracrine hepatopoietin potentiates AP-1 activity through JAB1 independent of MAPK pathway.

Many growth factors and cytokines are involved in liver regeneration. Of them, only hepatopoietin (HPO)/ALR (augmenter of liver regeneration) is a specifically hepatotrophic factor originally identified from the cytosol of regenerating or hyperplastic hepatic cells. Previous reports indicate that extracellular HPO triggers the MAPK pathway by binding its specific receptor on the cell surface. However, its function in the cytosol of hepatocytes is unclear. Here we identified that JAB1 (Jun activation domain-binding protein 1), a co-activator of AP-1, which is essential for liver regeneration, specifically interacts with intracellular HPO. JAB1 colocalizes with HPO in nuclei of hepatic cells or COS-7 cells. As an intracrine factor, the intracellular function of HPO is to increase c-Jun phosphorylation independent of c-Jun amino-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) -1 and -2, and leads to potentiation of JAB1-mediated AP-1 activation. Amino acids 1-63 of HPO molecule are sufficient to bind to JAB1, but the full-length HPO is necessary for its intracellular signaling. Taken together, these results elucidate a novel mechanism of intracrine cytokine signaling by specifically modulating the AP-1 pathway through JAB1, in a MAPK-independent fashion.

Animals↗