4-Phenylbutyric acid treatment rescues trafficking and processing of a mutant surfactant protein C

Mutations in the SFTPC gene, encoding surfactant protein–C (SP-C), are associated with interstitial lung disease (ILD). Knowledge of the intracellular fate of mutant SP-C is essential in the design of therapies to correct trafficking/processing of the proprotein, and to prevent the formation of cytotoxic aggregates. We assessed the potential of a chemical chaperone to correct the trafficking and processing of three disease-associated mutant SP-C proteins. HEK293 cells were stably transfected with wild-type (SP-C(WT)) or mutant (SP-C(L188Q), SP-C(Δexon4), or SP-C(I73T)) SP-C, and cell lines with a similar expression of SP-C mRNA were identified. The effects of the chemical chaperone 4-phenylbutyric acid (PBA) and lysosomotropic drugs on intracellular trafficking to the endolysosomal pathway and the subsequent conversion of SP-C proprotein to mature peptide were assessed. Despite comparable SP-C mRNA expression, proprotein concentrations varied greatly: SP-C(I73T) was more abundant than SP-C(WT) and was localized to the cell surface, whereas SP-C(Δexon4) was barely detectable. In contrast, SP-C(L188Q) and SP-C(WT) proprotein concentrations were comparable, and a small amount of SP-C(L188Q) was localized to the endolysosomal pathway. PBA treatment restored the trafficking and processing of SP-C(L188Q) to SP-C(WT) concentrations, but did not correct the mistrafficking of SP-C(I73T) or rescue SP-C(Δexon4). PBA treatment also promoted the aggregation of SP-C proproteins, including SP-C(L188Q). This study provides proof of the principle that a chemical chaperone can correct the mistrafficking and processing of a disease-associated mutant SP-C proprotein

Not Available

Not AvailableAn efficient protocol for shoot bud induction and proliferation employing half cotyledonary node with intact cotyledon explants derived from two-day-old seedlings of mung bean pre-conditioned on 6- benzylaminopurine (BAP) has been achieved. Explants were cultured for four weeks each on MS B5 + 12.5 μM BAP and MS B5 + 5 μM BAP +0.05 μM α- naphthaleneacetic acid (NAA ), respectively, as shoot bud induction and shoot elongation and proliferation media, gave the best regeneration response. The removal of the pre-existing buds from explants at 12 days in shoot bud induction medium led to enhanced regeneration response. Light microscopic observations on 14-day-old explants confirmed direct organogenesis route of regeneration. Elongated shoots (>2 cm) excised from the regenerating cultures were successfully rooted on half MS B5 medium containing 2.46 μM indolebutyric acid (IBA). About 90% of the rooted plantlets, efficiently hardened in pots having soil and farm yard manure, flowered and produced pods with viable seeds upon reaching maturity.Not Availabl