Parkinson's disease (PD), a neurological disease suited to gene therapy, is biochemically characterized by a severe decrease in the dopamine content of the striatum. One current strategy for gene therapy of PD involves local production of dopamine in the striatum achieved by inducing the expression of enzymes involved in the biosynthetic pathway for dopamine. We previously showed that the coexpression of tyrosine hydroxylase (TH) and aromatic-L-amino-acid decarboxylase (AADC), using two separate adeno-associated virus (AAV) vectors, resulted in more effective dopamine production and more remarkable behavioral recovery in 6-hydroxydopamine-lesioned parkinsonian rats, compared with the expression of TH alone. Not only levels of TH and AADC but also levels of tetrahydrobiopterin (BH4), a cofactor of TH, and GTP cyclohydrolase I (GCH), a rate-limiting enzymes for BH4 biosynthesis, are reduced in parkinsonian striatum. In the present study, we investigated whether transduction with separate AAV vectors expressing TH, AADC, and GCH was effective for gene therapy of PD. In vitro experiments showed that triple transduction with AAV-TH, AAV-AADC, and AAV-GCH resulted in greater dopamine production than double transduction with AAV-TH and AAV-AADC in 293 cells. Furthermore, triple transduction enhanced BH4 and dopamine production in denervated striatum of parkinsonian rats and improved the rotational behavior of the rats more efficiently than did double transduction. Behavioral recovery persisted for at least 12 months after stereotaxic intrastriatal injection. These results suggest that GCH, in addition to TH and AADC, is important for effective gene therapy of PD.
Pulmonary fibrosis, defined as the accumulation of connective tissue in the lungs, is a severe and often fatal form of interstitial lung disease. Transforming growth factor-beta (TGF-beta) is a powerful activator of connective tissue synthesis and fibroblast proliferation in the lung, and a critical paracrine signal for the development of pulmonary fibrosis. To investigate signaling pathways downstream of TGF- beta that contribute to lung fibrosis, TGF- beta stimulation of fibroblasts was replicated by treating NIH3T3 fibroblasts with conditioned medium (CM) from TGF- beta -treated type II alveolar epithelial cells (ATII cells). The data showed that fibroblast growth factor 2 (FGF-2) signaling is responsible for TGF-beta 1 CM-induced fibroblast proliferation, while it does not affect TGF-beta 1 CM-induced fibrotic differentiation. Moreover, fibroblast proliferation and differentiation induced by TGF- beta CM was totally abrogated by pretreatment of NIH3T3 cells with the specific ERK1/2 inhibitor, PD98059. These findings indicate that FGF-2 secreted by alveolar epithelial cells in response to TGF- beta 1 induces fibroblast proliferation and fibrotic activation through the ERK kinase pathway.
One potential strategy for gene therapy of Parkinson's disease (PD) is the local production of dopamine (DA) in the striatum induced by restoring DA-synthesizing enzymes. In addition to tyrosine hydroxylase (TH) and aromatic-L-amino-acid decarboxylase (AADC), GTP cyclohydrolase I (GCH) is necessary for efficient DA production. Using adeno-associated virus (AAV) vectors, we previously demonstrated that expression of these three enzymes in the striatum resulted in long-term behavioral recovery in rat models of PD. We here extend the preclinical exploration to primate models of PD. Mixtures of three separate AAV vectors expressing TH, AADC, and GCH, respectively, were stereotaxically injected into the unilateral putamen of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated monkeys. Coexpression of the enzymes in the unilateral putamen resulted in remarkable improvement in manual dexterity on the contralateral to the AAV-TH/-AADC/-GCH-injected side. Behavioral recovery persisted during the observation period (four monkeys: 48 days, 65 days, 50 days, and >10 months, each). TH-immunoreactive (TH-IR), AADC-IR, and GCH-IR cells were present in a large region of the putamen. Microdialysis demonstrated that concentrations of DA in the AAV-TH/-AADC/-GCH-injected putamen were increased compared with the control side. Our results show that AAV vectors efficiently introduce DA-synthesizing enzyme genes into the striatum of primates with restoration of motor functions. This triple transduction method may offer a potential therapeutic strategy for PD.
Hedgehog (Hh) signaling pathway and Cyclin E are key players in cell proliferation and organ development. Hyperactivation of hh and cyclin E has been linked to several types of cancer. However, coordination of the expression of hh and cyclin E was not well understood. Here we show that an evolutionarily conserved transcription factor Apontic (Apt) directly activates hh and cyclin E through its binding site in the promoter regions of hh and cyclin E. This Apt-dependent proper expression of hh and cyclin E is required for cell proliferation and development of the Drosophila wing. Furthermore, Fibrinogen silencer-binding protein (FSBP), a mammalian homolog of Apt, also positively regulates Sonic hh (Shh), Desert hh (Dhh), Cyclin E1 (CCNE1) and Cyclin E2 (CCNE2) in cultured human cells, suggesting evolutionary conservation of the mechanism. Apt-mediated expression of hh and cyclin E can direct proliferation of Hh-expressing cells and simultaneous growth, patterning and differentiation of Hh-recipient cells. The discovery of the simultaneous expression of Hh and principal cell-cycle regulator Cyclin E by Apt implicates insight into the mechanism by which deregulated hh and cyclin E promotes tumor formation.
The NAC transcription factor RIF (Ripening Inducing Factor) was previously reported to be necessary for the ripening of octoploid strawberry (Fragaria × ananassa) fruit, but the mechanistic basis of RIF-mediated transcriptional regulation and how RIF activity is modulated remains elusive. Here we show that FvRIF in diploid strawberry, Fragaria vesca, is a key regulator in the control of fruit ripening, and that knockout mutations of FvRIF result in a complete block of fruit ripening. DNA affinity purification sequencing coupled with transcriptome deep sequencing suggests that 2080 genes are direct targets of FvRIF-mediated regulation, including those related to various aspects of fruit ripening. We provide evidence that FvRIF modulates anthocyanin biosynthesis and fruit softening by directly regulating the related core genes. Moreover, we demonstrate that FvRIF interacts with and serves as a substrate of mitogen-activated protein kinase 6 (FvMAPK6), which regulates the transcriptional activation function of FvRIF by phosphorylating FvRIF at Thr-310. Our findings uncover the FvRIF-mediated transcriptional regulatory network in controlling strawberry fruit ripening and highlight the physiological significance of phosphorylation modification on FvRIF activity in ripening.
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