bims-micpro 2024-03-31 papers

Issue of 2024‒03‒31
three papers selected by
Thomas Farid Martínez, University of California, Irvine

Methods Mol Biol. 2024 ;2758 375-385

Intracellular and Extracellular Peptidomes of the Model Plant, Physcomitrium patens.

Here, we report our approach to peptidomic analysis of the plant model Physcomitrium patens. Intracellular and extracellular peptides were extracted under conditions preventing proteolytic digestion by endogenous proteases. The extracts were fractionated on size exclusion columns to isolate intracellular peptides and on reversed-phase cartridges to isolate extracellular peptides, with the isolated peptides subjected to LC-MS/MS analysis. Mass spectrometry data were analyzed for the presence of peptides derived from the known proteins or microproteins encoded by small open reading frames (<100 aa, smORFs) predicted in the moss genome. Experimental details are provided for each step.

Keywords: Mass spectrometry; Peptidomics; Physcomitrium patens; Size exclusion chromatography; Solid phase extraction

DOI: https://doi.org/10.1007/978-1-0716-3646-6_20

Aging Cell. 2024 Mar 22. e14153

Humanin variant P3S is associated with longevity in APOE4 carriers and resists APOE4-induced brain pathology.

Brendan Miller, Su-Jeong Kim, Kevin Cao, Hemal H Mehta, Neehar Thumaty, Hiroshi Kumagai, Tomomitsu Iida, Cassandra McGill, Christian J Pike, Kamila Nurmakova, Zachary A Levine, Patrick M Sullivan, Kelvin Yen, Nilüfer Ertekin-Taner, Gil Atzmon, Nir Barzilai, Pinchas Cohen.

The APOE4 allele is recognized as a significant genetic risk factor to Alzheimer's disease (AD) and influences longevity. Nonetheless, some APOE4 carriers exhibit resistance to AD even in advanced age. Humanin, a mitochondrial-derived peptide comprising 24 amino acids, has variants linked to cognitive resilience and longevity. Our research uncovered a unique humanin variant, P3S, specifically enriched in centenarians with the APOE4 allele. Through in silico analyses and subsequent experimental validation, we demonstrated a strong affinity between humanin P3S and APOE4. Utilizing an APOE4-centric mouse model of amyloidosis (APP/PS1/APOE4), we observed that humanin P3S significantly attenuated brain amyloid-beta accumulation compared to the wild-type humanin. Transcriptomic assessments of mice treated with humanin P3S highlighted its potential mechanism involving the enhancement of amyloid beta phagocytosis. Additionally, in vitro studies corroborated humanin P3S's efficacy in promoting amyloid-beta clearance. Notably, in the temporal cortex of APOE4 carriers, humanin expression is correlated with genes associated with phagocytosis. Our findings suggest a role of the rare humanin variant P3S, especially prevalent among individuals of Ashkenazi descent, in mitigating amyloid beta pathology and facilitating phagocytosis in APOE4-linked amyloidosis, underscoring its significance in longevity and cognitive health among APOE4 carriers.

Keywords: Alzheimer's disease; humanin; longevity; microprotein; mitochondrial DNA variation; small open reading frame

DOI: https://doi.org/10.1111/acel.14153

PLoS Pathog. 2024 Mar 28. 20(3): e1012129

A novel sORF gene mutant strain of Yersinia pestis vaccine EV76 offers enhanced safety and improved protection against plague.

Xiao Guo, Youquan Xin, Zehui Tong, Shiyang Cao, Yuan Zhang, Gengshan Wu, Hongyan Chen, Tong Wang, Yajun Song, Qingwen Zhang, Ruifu Yang, Zongmin Du.

We recently identified two virulence-associated small open reading frames (sORF) of Yersinia pestis, named yp1 and yp2, and null mutants of each individual genes were highly attenuated in virulence. Plague vaccine strain EV76 is known for strong reactogenicity, making it not suitable for use in humans. To improve the immune safety of EV76, three mutant strains of EV76, Δyp1, Δyp2, and Δyp1&yp2 were constructed and their virulence attenuation, immunogenicity, and protective efficacy in mice were evaluated. All mutant strains were attenuated by the subcutaneous (s.c.) route and exhibited more rapid clearance in tissues than the parental strain EV76. Under iron overload conditions, only the mice infected with EV76Δyp1 survived, accompanied by less draining lymph nodes damage than those infected by EV76. Analysis of cytokines secreted by splenocytes of immunized mice found that EV76Δyp2 induced higher secretion of multiple cytokines including TNF-α, IL-2, and IL-12p70 than EV76. On day 42, EV76Δyp2 or EV76Δyp1&yp2 immunized mice exhibited similar protective efficacy as EV76 when exposed to Y. pestis 201, both via s.c. or intranasal (i.n.) routes of administration. Moreover, when exposed to 200-400 LD50 Y. pestis strain 201Δcaf1 (non-encapsulated Y. pestis), EV76Δyp2 or EV76Δyp1&yp2 are able to afford about 50% protection to i.n. challenges, significantly better than the protection afforded by EV76. On 120 day, mice immunized with EV76Δyp2 or EV76Δyp1&yp2 cleared the i.n. challenge of Y. pestis 201-lux as quickly as those immunized with EV76, demonstrating 90-100% protection. Our results demonstrated that deletion of the yp2 gene is an effective strategy to attenuate virulence of Y. pestis EV76 while improving immunogenicity. Furthermore, EV76Δyp2 is a promising candidate for conferring protection against the pneumonic and bubonic forms of plague.

DOI: https://doi.org/10.1371/journal.ppat.1012129