BORC complex specific components and Kinesin-1 mediate autophagy evasion by the autophagy-resistant Mycobacterium tuberculosis Beijing strain

Cerebrospinal fluid proteomics identification of biomarkers for amyloid and tau PET stages

Accurate staging of Alzheimer's disease (AD) pathology is crucial for therapeutic trials and prognosis, but existing fluid biomarkers lack specificity, especially for assessing tau deposition severity, in amyloid-beta (Aβ)-positive patients. We analyze cerebrospinal fluid (CSF) samples from 136 participants in the Alzheimer's Disease Neuroimaging Initiative using more than 6,000 proteins. We apply machine learning to predict AD pathological stages defined by amyloid and tau positron emission tomography (PET). We identify two distinct protein panels: 16 proteins, including neurofilament heavy chain (NEFH) and SPARC-related modular calcium-binding protein 1 (SMOC1), that distinguished Aβ-negative/tau-negative (A-T-) from A+ individuals and nine proteins, such as HCLS1-associated protein X-1 (HAX1) and glucose-6-phosphate isomerase (GPI), that differentiated A+T+ from A+T- stages. These signatures outperform the established CSF biomarkers (area under the curve [AUC]: 0.92 versus 0.67-0.70) and accurately predicted disease progression over a decade. The findings are validated in both internal and external cohorts. These results underscore the potential of proteomic-based signatures to refine AD diagnostic criteria and improve patient stratification in clinical trials.

Chemical genetic screens reveal defective lysosomal trafficking as synthetic lethal with NF1 loss

Neurofibromatosis type 1, a genetic disorder caused by pathogenic germline variations in NF1, predisposes individuals to the development of tumors, including cutaneous and plexiform neurofibromas (CNs and PNs), optic gliomas, astrocytomas, juvenile myelomonocytic leukemia, high-grade gliomas and malignant peripheral nerve sheath tumors (MPNSTs), which are chemotherapy- and radiation-resistant sarcomas with poor survival. Loss of NF1 also occurs in sporadic tumors, such as glioblastoma (GBM), melanoma, breast, ovarian and lung cancers. We performed a high-throughput screen for compounds that were synthetic lethal with NF1 loss, which identified several leads, including the small molecule Y102. Treatment of cells with Y102 perturbed autophagy, mitophagy and lysosome positioning in NF1-deficient cells. A dual proteomics approach identified BLOC-one-related complex (BORC), which is required for lysosome positioning and trafficking, as a potential target of Y102. Knockdown of a BORC subunit using siRNA recapitulated the phenotypes observed with Y102 treatment. Our findings demonstrate that BORC might be a promising therapeutic target for NF1-deficient tumors.

Bmpali, Bmb1 and Bmcap are necessary for uric acid granule formation in Bombyx mori

Uric acid is the end-product of nitrogen metabolism of the silkworm and other lepidopterans. The accumulation of uric acid particles in the epidermis causes the larval silkworm to appear white and opaque. However, the mechanism of uric acid granule formation is still unclear. Silkworm epidermis color is linked to the genes responsible for uric acid particle formation. We first identified two genes in the Bombyx mori genome that encode subunits of the Bloc-1 (Biogenesis of Lysosome-related Organelles Complex-1) by homology to these genes in other eukaryotes, Bmpali and Bmb1. Mutation in these genes caused a transparent phenotype in the silkworm larvae, and the loss of BmBloc-1 subunit gene Bmcap resulted in the same phenotype. These three genes are highly conserved between human and silkworm. We discovered that Bmpali, Bmcap, and Bmb1 localize in the cytoplasm of BmN cells. Yeast two-hybrid assays demonstrated that the Bmpali physically interacts with both Bmcap and Bmb1. Investigating the roles of Bmpali, Bmb1, and Bmcap is essential for uric acid granule formation understanding in Bombyx mori. These mutants present a valuable silkworm model for studying the biogenesis of lysosome-related organelles (LROs).