DHCR7 Expression Predicts Poor Outcomes and Mortality From Sepsis

Multiomic molecular patterns of lipid dysregulation in a subphenotype of sepsis with higher shock incidence and mortality

BACKGROUND

Lipids play a critical role in defense against sepsis. We sought to investigate gene expression and lipidomic patterns of lipid dysregulation in sepsis.

METHODS

Data from four adult sepsis studies were analyzed and findings were investigated in two external datasets. Previously characterized lipid dysregulation subphenotypes of hypolipoprotein (HYPO; low lipoproteins, increased mortality) and normolipoprotein (NORMO; higher lipoproteins, lower mortality) were studied. Leukocytes collected within 24 h of sepsis underwent RNA sequencing (RNAseq) and shotgun plasma lipidomics was performed.

RESULTS

Of 288 included patients, 43% were HYPO and 57% were NORMO. HYPO patients exhibited higher median SOFA scores (9 vs 5, p = < 0.001), vasopressor use (67% vs 34%, p = < 0.001), and 28-day mortality (30% vs 16%, p = 0.004). Leukocyte RNAseq identified seven upregulated lipid metabolism genes in HYPO (PCSK9, DHCR7, LDLR, ALOX5, PLTP, FDFT1, and MSMO1) vs. NORMO patients. Lipidomics revealed lower cholesterol esters (CE, adjusted p = < 0.001), lysophosphatidylcholines (LPC, adjusted p = 0.001), and sphingomyelins (SM, adjusted p = < 0.001) in HYPO patients. In HYPO patients, DHCR7 expression strongly correlated with reductions in CE, LPC, and SM (p < 0.01), while PCSK9, MSMO1, DHCR7, PLTP, and LDLR upregulation were correlated with low LPC (p < 0.05). DHCR7, ALOX5, and LDLR correlated with reductions in SM (p < 0.05). Mortality and phenotype comparisons in two external datasets (N = 824 combined patients) corroborated six of the seven upregulated lipid genes (PCSK9, DHCR7, ALOX5, PLTP, LDLR, and MSMO1).

CONCLUSION

We identified a genetic lipid dysregulation signature characterized by seven lipid metabolism genes. Five genes in HYPO sepsis patients most strongly correlated with low CE, LPC, and SMs that mediate cholesterol storage and innate immunity.

AEBS inhibition in macrophages: Augmenting reality for SERMs repurposing against infections

Beyond their clinical use as selective estrogen receptor modulators (SERMs), raloxifene and tamoxifen have attracted recent attention for their favorable activity against a broad range of dangerous human pathogens. While consistently demonstrated to occur independently on classic estrogen receptors, the mechanisms underlying SERMs antimicrobial efficacy remain still poorly elucidated, but fundamental to benefit from repurposing strategies of these drugs. Macrophages are innate immune cells that protect from infections by rapidly reprogramming their metabolic state, particularly cholesterol disposal, which is at the center of an appropriate macrophage immune response as well as of the anabolic requirements of both the pathogen and the host cells. The microsomal antiestrogen binding site (AEBS) comprises enzymes involved in the last stages of cholesterol biosynthesis and is a high affinity off-target site for SERMs. We review here recent findings from our laboratory and other research groups in support of the hypothesis that AEBS multiprotein complex represents the candidate pre-genomic target of SERMs immunomodulatory activity. The cholesterol restriction resulting from SERMs-mediated AEBS inhibition may be responsible for boosting inflammatory and antimicrobial pathways that include inflammasome activation, modulation of Toll-like receptors (TLRs) responses, induction of interferon regulatory factor (IRF3) and nuclear factor erythroid 2-related factor 2 (NRF2)-mediated transcriptional programs and, noteworthy, the mitigation of excessive inflammatory and proliferative responses, leading to the overall potentiation of the macrophage response to infections.

Exploration of transcriptional regulation network between buffalo oocytes and granulosa cells and its impact on different diameter follicles

BACKGROUND

Buffalo is a globally important livestock species, but its reproductive performance is relatively low than cattles. At present, dominant follicle development specific process and mechanistic role of follicular growth related genes in water buffaloes are not well understood. Therefore, we comprehensively performed transcriptomics of granulosa cells and oocytes from different-sized follicles in water buffalo to identify key candidate genes that influence follicle development and diameter, and further explored the potential regulatory mechanisms of granulosa cells and oocytes in the process of water buffalo follicle development.

RESULTS

In this study, we found918 granulosa cell transcripts and 1401 oocyte transcripts were correlated in follicles of different diameters, and the expression differences were significant. Subsequent enrichment analysis of the co-expressed differentially expressed transcripts identified several genes targeted by long non-coding RNAs (lncRNAs) and associated with follicular development. Notably, the upregulation of BUB1 regulated by MSTRG.41325.4 and interactive action of SMAD2 and SMAD7 might have key regulatory role in follicular development. Additionally, we also detected key differentially expressed genes that potentially influence follicular hormone metabolism and growth, like ID2, CHRD, TGIF2 and MAD2L1, and constructed an interaction network between lncRNA transcripts and mRNAs.

CONCLUSIONS

In summary, this study preliminarily revealed the differences in gene expression patterns among buffalo follicles of different sizes and their potential molecular regulatory mechanisms. It provides a new perspective for exploring the mechanism of buffalo follicular dominance and improving buffalo reproductive performance.

Lipidomic changes in a novel sepsis outcome-based analysis reveals potent pro-inflammatory and pro-resolving signaling lipids

The purpose of this study was to investigate changes in the lipidome of patients with sepsis to identify signaling lipids associated with poor outcomes that could be linked to future therapies. Adult patients with sepsis were enrolled within 24h of sepsis recognition. Patients meeting Sepsis-3 criteria were enrolled from the emergency department or intensive care unit and blood samples were obtained. Clinical data were collected and outcomes of rapid recovery, chronic critical illness (CCI), or early death were adjudicated by clinicians. Lipidomic analysis was performed on two platforms, the Sciex™ 5500 device to perform a lipidomic screen of 1450 lipid species and a targeted signaling lipid panel using liquid-chromatography tandem mass spectrometry. For the lipidomic screen, there were 274 patients with sepsis: 192 with rapid recovery, 47 with CCI, and 35 with early deaths. CCI and early death patients were grouped together for analysis. Fatty acid (FA) 12:0 was decreased in CCI/early death, whereas FA 17:0 and 20:1 were elevated in CCI/early death, compared to rapid recovery patients. For the signaling lipid panel analysis, there were 262 patients with sepsis: 189 with rapid recovery, 45 with CCI, and 28 with early death. Pro-inflammatory signaling lipids from ω-6 poly-unsaturated fatty acids (PUFAs), including 15-hydroxyeicosatetraenoic (HETE), 12-HETE, and 11-HETE (oxidation products of arachidonic acid [AA]) were elevated in CCI/early death patients compared to rapid recovery. The pro-resolving lipid mediator from ω-3 PUFAs, 14(S)-hydroxy docosahexaenoic acid (14S-HDHA), was also elevated in CCI/early death compared to rapid recovery. Signaling lipids of the AA pathway were elevated in poor-outcome patients with sepsis and may serve as targets for future therapies.