JCI insight最新文献

Mitochondrial trifunctional protein (TFP) deficiency is an inherited metabolic disorder leading to a block in long-chain fatty acid β-oxidation. Mutations in either HADHA and HADHB, which encode the TFPα and β subunits, respectively, usually result in combined TFP deficiency. A single common mutation, HADHA c.1528G>C (p.E510Q), leads to isolated 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency. TFP also catalyzes a step in the remodeling of cardiolipin (CL), a phospholipid critical to mitochondrial membrane stability and function. We explored the effect of mutations in TFP subunits on CL and other phospholipid content and composition and the consequences of these changes on mitochondrial bioenergetics in patient-derived fibroblasts. Abnormalities in these parameters varied extensively among different fibroblasts, and some cells were able to maintain basal oxygen consumption rates similar to controls. Although CL reduction was universally identified, a simultaneous increase in monolysocardiolipins was discrepant among cells. A similar profile was seen in liver mitochondria isolates from a TFP-deficient mouse model. Response to new potential drugs targeting cardiolipin metabolism might be dependent on patient genotype.

Background: An HIV-1 DNA vaccine composed of seven highly conserved, structurally important elements (Conserved Elements, CE) of HIV p24Gag was tested in a phase I randomized, double-blind clinical trial (HVTN 119, NCT03181789) in people without HIV. A CE prime- CE+full-length p55Gag boost DNA vaccine was compared to p55Gag DNA vaccination only.

Methods: Two groups (n=25 each) received 4 DNA vaccinations [2xCE prime- 2xCE+p55Gag boost or 4x p55Gag] by intramuscular injection/electroporation, including IL-12 DNA adjuvant. The placebo group (n=6) received saline. Participants were followed for safety and tolerability. Immunogenicity was assessed for T cell and antibody responses.

Results: Both regimens were safe and generally well-tolerated. The p24CE vaccine was immunogenic (29% CD4+ and 4% CD8+ responders) and was significantly boosted by CE+p55Gag (64% CD4+, p=0.037; 42% CD8+, p=0.004). CE+p55Gag induced CD4+ responses to 5 of 7 CE, compared to only 2 CE by p55Gag DNA alone, with a higher reponse to CE5 in 30% of individuals (p=0.006). CE+p55Gag induced significantly higher mean CD4+ CE Tcell breadth (0.68 vs 0.22 CE; p=0.029) and a strong trend for increased CD4+ and CD8+ T-cell breadth (1.14 vs. 0.52 CE; p=0.051) compared to p55Gag alone. Both groups developed high p55Gag T-cell (91% each) and p24Gag antibody (91% vs. 80%) responses. p24CE vaccine-induced CD4+ CE T-cell responses correlated (p=0.007) with p24Gag antibody responses.

Conclusion: The combination CE/CE+p55Gag DNA vaccine induced T-cell immune responses to conserved regions in p24Gag resulting in significant increases in breadth and epitope recognition throughout p55Gag. Vaccines able to focus immune responses by priming responses to highly conserved regions could be part of a comprehensive HIV vaccine strategy.

Trial registration:

Clinical trials: gov NCT03181789 Study URL: https://www.

Clinicaltrials: gov/search?term=NCT03181789 FUNDING. HIV vaccine trial network (HVTN), NIAID/NIH.

Background: A polymorphism in the fat mass and obesity-associated gene (FTO) is linked to enhanced neural sensitivity to food-cues and attenuated ghrelin suppression. Risk allele carriers regain more weight than non-carriers after bariatric surgery. It remains unclear how FTO variation affects brain function and ghrelin following surgery.

Methods: Resting-state functional magnetic resonance imaging (RS-fMRI) and cue-reactivity fMRI with high-/low-caloric food-cues were performed at pre-surgery and 1-, 6-, and 12-months post-surgery to examine brain function in 16 carriers with one copy of the rs9939609 A allele (AT) and 26 non-carriers (TT). Behavioral assessments up to five years post-surgery were also conducted.

Results: AT relative to TT group had smaller BMI-loss at 12 to 60 months post-surgery and lower resting-state activity in posterior cingulate cortex following LSG (group-by-time interaction effects). Meanwhile, AT relative to TT group showed greater food-cue responses in dorsolateral prefrontal cortex (DLPFC), dorsomedial prefrontal cortex (DMPFC) and insula (group effects). There were negative associations of weight-loss with ghrelin and greater activation in DLPFC, DMPFC and insula in AT but not TT group.

Conclusion: These findings indicate that FTO variation is associated with the evolution of ghrelin signaling and brain function after bariatric surgery, which might hinder weight-loss.

Rift Valley fever (RVF) is an emerging arboviral disease affecting both humans and livestock. In humans, RVF displays a spectrum of clinical manifestations, including encephalitis. To date, there are no FDA-approved vaccines or therapeutics for human use, although several are in pre-clinical development. Few small animal models of RVF encephalitis exist, further complicating countermeasure assessment. Human mAbs RVFV-140, RVFV-268 and RVFV-379 are recombinant potently neutralizing antibodies that prevent infection by binding the RVFV surface glycoproteins. Previous studies showed that both RVFV-268 and RVFV-140 improve survival in a lethal mouse model of disease, and RVFV-268 has prevented vertical transmission in a pregnant rat model of infection. Despite these successes, evaluation of mAbs in the context of brain disease has been limited. This is the first study to assess neutralizing antibodies for prevention of RVF neurologic disease using a rat model. Administration of RVFV-140, RVFV-268, or RVFV-379 twenty-four hours prior to aerosol exposure to the virulent ZH501 strain of RVFV results in substantially enhanced survival and lack of neurological signs of disease. These results using a stringent and highly lethal aerosol infection model supports the potential use of human mAbs to prevent the development of RVF encephalitis.

Graft-versus-host disease (GvHD) is a life-threatening complication frequently occurring following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Since gut microbiota and regulatory T cells (Tregs) are believed to play roles in GvHD prevention, we investigated whether DP8a Tregs, which we have previously described to harbor a TCR-specificity for the gut commensal Faecalibacterium prausnitzii, could protect against GvHD, thereby linking microbiota and its effect on GvHD. We observed a decrease in CD73+ DP8α Treg frequency in allo-HSCT patients at 1-month post-transplantation, which was associated with aGvHD development at 1-month post-transplantation, as compared to aGvHD-free patients, without being correlated to hematological disease's relapse. Importantly, CD73 activity was shown to be critical for DP8αTreg suppressive function. Moreover, the frequency of host-reactive DP8α Tregs was also lower in aGvHD patients, as compared to aGvHD-free patients, which could embody a protective mechanism responsible for the maintenance of these cell subset in GvHD-free patients. We also showed that human DP8α Tregs protected mice against xeno-GvHD through limiting deleterious inflammation and preserving gut integrity. Altogether, these results demonstrated that human DP8α Tregs mediate aGvHD prevention in a CD73-dependent manner, likely through host-reactivity, advocating for the use of these cells for the development of innovative therapeutic strategies to preclude aGvHD-related inflammation.

Diamond-Blackfan anemia syndrome (DBA) is a ribosomopathy associated with loss-of-function variants in more than 20 ribosomal protein (RP) genes. Here, we report the genetic, functional and biochemical dissection of two multigenerational pedigrees with variants in RPL17, a large ribosomal subunit protein-encoding gene. Affected individuals had clinical features and erythroid proliferation defects consistent with DBA. Furthermore, RPL17/uL22 depletion resulted in anemia and micrognathia in zebrafish larvae, and in vivo complementation studies indicated that RPL17 variants were pathogenic. Lymphoblastoid cell lines (LCLs) derived from patients displayed a ribosomal RNA maturation defect reflecting haploinsufficiency of RPL17. The proteins encoded by RPL17 variants were not incorporated into ribosomes, but 10-20% of 60S ribosomal subunits contained a short form of 5.8S rRNA (5.8SC), a species that is marginal in normal cells. These atypical 60S subunits were actively engaged in translation. Ribosome profiling showed changes of the translational profile, but those are similar to LCLs bearing RPS19 variants. These results link an additional RP gene to DBA. They show that ribosomes can be modified substantially by RPL17 haploinsufficiency, but support the paradigm that translation alterations in DBA are primarily related to insufficient ribosome production rather than to changes in ribosome structure or composition.

Congenital myasthenic syndrome-22 (CMS22, OMIM 616224) is a rare genetic disorder caused by deleterious genetic variation in the prolyl endopeptidase-like (PREPL) gene. Previous reports have described patients with deletions and nonsense variants in PREPL, but nothing is known about the effect of missense variants in the pathology of CMS22. In this study, we have functionally characterized missense variants in PREPL from three CMS22 patients, all with hallmark phenotypes. Biochemical evaluation revealed that these missense variants do not impair hydrolase activity, thereby challenging the conventional diagnostic criteria and disease mechanism. Structural analysis showed that the variants affect regions most likely involved in intra-protein or protein-protein interactions. Indeed, binding to a selected group of known interactors was differentially reduced for the three mutants. The importance of non-hydrolytic functions of PREPL was investigated in catalytically inactive PREPL p.Ser559Ala cell lines which showed that hydrolytic activity of PREPL is needed for normal mitochondrial function but not for regulating AP1-mediated transport in the trans-Golgi network. In conclusion, these studies showed that CMS22 can be caused not only by deletion and truncation of PREPL but also by missense variants that do not necessarily result in a loss of hydrolytic activity of PREPL.

Thrombospondin-1 (TSP1) is a matricellular protein associated with the regulation of cell migration through direct binding interactions with integrin proteins and by associating with other receptors known to regulate integrin function, including CD47 and CD36. We previously demonstrated that deletion of an epithelial TSP1 receptor CD47 attenuates epithelial wound repair following intestinal mucosal injury. However, the mechanisms by which TSP1 contributes to intestinal mucosal repair remains poorly understood. Our results show upregulated TSP1 expression in colonic mucosal wounds and impaired intestinal mucosal wound healing in vivo upon intestinal epithelial specific loss of TSP1 (VillinCre/+Thbs1f/f or Thbs1ΔIEC). We report that exposure to exogenous TSP1 enhanced migration of IECs in a CD47- and TGFβ1-dependent manner, and that deficiency of TSP1 in primary murine colonic epithelial cells resulted in impaired wound healing. Mechanistically, TSP1 modulated epithelial actin cytoskeletal dynamics by suppression of RhoA activity, activation of Rac1, and changes in F-actin bundling. Overall, TSP1 was found to regulate intestinal mucosal wound healing via CD47 and TGFβ1, coordinate integrin-containing cell-matrix adhesion dynamics and remodel the actin cytoskeleton in migrating epithelial cells to enhance cell motility and promote wound repair.

The role of different biological variables including biological sex, age, and sex hormones in HIV cure approaches is not well understood. The γc-cytokine IL-15 is a clinically relevant cytokine that promotes immune activation and mediates HIV reactivation from latency. In this work, we examine the interplay that biological sex, age, and sex hormones 17β-estradiol, progesterone, and testosterone may have on the biological activity of IL-15. We found that IL-15-mediated CD4 T cell activation was higher in female donors compared to male donors. This difference was abrogated at high 17β-estradiol concentration. Additionally, there was a positive correlation between age and both IL-15-mediated CD8 T cell activation and IFN-γ production. In a primary cell model of latency, biological sex, age, or sex hormones did not influence the ability of IL-15 to reactivate latent HIV. Finally, 17β-estradiol did not consistently affect reactivation of translation-competent reservoirs in CD4 T cells from ART-suppressed people living with HIV. Our study has found that biological sex and age, but not sex hormones, may influence some of the biological activities of IL-15. Understanding how different biological variables affect the biological activity of cure therapies will help us evaluate current and future clinical trials aimed towards HIV cure in diverse populations.

The clinical therapy for treating acute myocardial infarction is primary percutaneous coronary intervention (PPCI). PPCI is effective at reperfusing the heart, however the rapid re-introduction of blood can cause ischemia-reperfusion (I/R). Reperfusion injury is responsible for up to half of the final myocardial damage, but there are no pharmacological interventions to reduce I/R. We previously demonstrated that inhibiting monocarboxylate transporter 4 (MCT4) and re-directing pyruvate towards oxidation can blunt hypertrophy. We hypothesized this pathway might be important during I/R. Here, we establish that the pyruvate-lactate axis plays a role in determining myocardial salvage following injury. Post-I/R, the mitochondrial pyruvate carrier (MPC), required for pyruvate oxidation, is upregulated in the surviving myocardium. In cardiomyocytes lacking the MPC, there was increased cell death and less salvage after I/R, which was associated with an upregulation of MCT4. To determine the importance of pyruvate oxidation, we inhibited MCT4 with a small-molecule drug (VB124) at reperfusion. This strategy normalized reactive oxygen species (ROS), mitochondrial membrane potential (∆Ψ), and Ca2+, increased pyruvate entry to TCA cycle, increased oxygen consumption, improved myocardial salvage and functional outcomes following I/R. Our data suggests normalizing pyruvate-lactate metabolism by inhibiting MCT4 is a promising therapy to mitigate I/R injury.