A late presentation of TPM3 myopathy presenting as sleep hypoventilation in the setting of acute demyelinating encephalomyelitis.

Central hypoventilation is a rare cause of respiratory failure that has been associated with multiple underlying disorders, including congenital central hypoventilation syndrome, obesity hypoventilation syndrome, and several neuromuscular conditions. We report the case of an adolescent who presented with respiratory failure in the setting of acute demyelinating encephalomyelitis whose clinical history was consistent with a congenital myopathy and whom we found to have a Tropomyosin 3 (TPM3) genetic variant on further genetic testing. This case expands the clinical spectrum of causes for late-onset central hypoventilation in the setting of a neuromuscular disorder. CITATION: Stringel V, Bizargity P, Laureta E, Kothare S. A late presentation of TPM3 myopathy presenting as sleep hypoventilation in the setting of acute demyelinating encephalomyelitis. J Clin Sleep Med. 2022;18(11):2695-2698.

A homozygous splice variant in ATP5PO, disrupts mitochondrial complex V function and causes Leigh syndrome in two unrelated families.

Mitochondrial complex V plays an important role in oxidative phosphorylation by catalyzing the generation of ATP. Most complex V subunits are nuclear encoded and not yet associated with recognized Mendelian disorders. Using exome sequencing, we identified a rare homozygous splice variant (c.87+3A>G) in ATP5PO, the complex V subunit which encodes the oligomycin sensitivity conferring protein, in three individuals from two unrelated families, with clinical suspicion of a mitochondrial disorder. These individuals had a similar, severe infantile and often lethal multi-systemic disorder that included hypotonia, developmental delay, hypertrophic cardiomyopathy, progressive epileptic encephalopathy, progressive cerebral atrophy, and white matter abnormalities on brain MRI consistent with Leigh syndrome. cDNA studies showed a predominant shortened transcript with skipping of exon 2 and low levels of the normal full-length transcript. Fibroblasts from the affected individuals demonstrated decreased ATP5PO protein, defective assembly of complex V with markedly reduced amounts of peripheral stalk proteins, and complex V hydrolytic activity. Further, expression of human ATP5PO cDNA without exon 2 (hATP5PO-∆ex2) in yeast cells deleted for yATP5 (ATP5PO homolog) was unable to rescue growth on media which requires oxidative phosphorylation when compared to the wild type construct (hATP5PO-WT), indicating that exon 2 deletion leads to a non-functional protein. Collectively, our findings support the pathogenicity of the ATP5PO c.87+3A>G variant, which significantly reduces but does not eliminate complex V activity. These data along with the recent report of an affected individual with ATP5PO variants, add to the evidence that rare biallelic variants in ATP5PO result in defective complex V assembly, function and are associated with Leigh syndrome.

A Rare Case Report of 17q23.1q23.2 Microdeletion With Homozygosity of 11p11.2q13.4 in a Newborn.

We present the case of a newborn with 17q23.1q23.2 microdeletion and additional homozygosity of 11p11.2q13.4. In the literature, 17q23.1q23.2 microdeletion syndrome is a novel syndrome reported in nine patients. Our patient is a full-term baby boy admitted to a neonatal intensive care unit for hypoglycemia, respiratory distress, presumed sepsis, and thrombocytopenia. General appearance revealed microcephaly, micrognathia, ankyloglossia, small mouth, and high arch palate. The patient also presented with hypotonia, poor feeding, and poor weight gain in the first week of life followed by hypertonia and tremors from the second week of life. The phenotypic and clinical presentation lead to the genetic investigation of microarray which revealed 17q23.1q23.2 microdeletion and additional homozygosity of 11p11.2q13.4.

GNA11 brain somatic pathogenic variant in an individual with phacomatosis pigmentovascularis.

OBJECTIVE: To describe the findings of histopathology and genotyping studies in affected brain tissue from an individual with phacomatosis pigmentovascularis (PPV). METHODS: A retrospective chart review of a 2-year 10-month-old male with a clinical diagnosis of PPV cesiomarmorata (or type V) was performed. Clinical features, brain imaging and histopathology findings, and genotyping studies in his affected brain tissue are summarized. RESULTS: The proband had a clinically severe neurologic phenotype characterized by global developmental delay, generalized hypotonia, and recurrent episodes of cardiac asystole in the setting of status epilepticus. A somatic pathogenic variant in GNA11 (c.547C>T, p.Arg183Cys) was detected in his skin tissue but not in blood (previously published). He underwent an urgent left posterior quadrantectomy for his life-threatening seizures. Histopathology of resected brain tissue showed an increase in leptomeningeal melanocytes and abnormal vasculature, and the exact pathogenic variant in GNA11 (c.547C>T, p.Arg183Cys), previously isolated from his skin tissue but not blood, was detected in his resected brain tissue. CONCLUSIONS: The finding of this variant in affected skin and brain tissue of our patient with PPV supports a unifying genetic diagnosis of his neurocutaneous features.

Inhibitory effects of pirfenidone on dendritic cells and lung allograft rejection.

BACKGROUND: Pirfenidone (PFD) is an antifibrotic agent with beneficial effects on proinflammatory disorders. In this study, we further investigated PFD and long-acting form, "deuterated PFD," immune-modulating properties by evaluating their effects on mouse dendritic cells (DCs). METHODS: The effects of PFD on DCs were examined in vivo using an orthotopic mouse lung transplant model and in vitro using isolated bone marrow-derived DCs in response to lipopolysaccharide and allogeneic stimulation. RESULTS: In mouse lung transplants, PFD and deuterated PFD treatment improved allograft lung function based on peak airway pressure, less infiltrates/consolidation on micro-computed tomography scan imaging, and reduced lung rejection/injury. DC activation from lung allografts was suppressed with PFD, and there seemed to be a greater effect of PFD on CD11c(+)CD11b(-)CD103(+) lung DCs. In addition, PFD reduced the expression of several proinflammatory cytokines/chemokines from lung allografts. In vitro, DCs treated with PFD showed decreased expression of major histocompatibility complex class II and costimulatory molecules and the capacity of these DCs to stimulate T-cell activation was impaired, although antigen uptake was preserved. PFD directly inhibited the release of inflammatory cytokines from isolated DCs, was associated with a reduction of stress protein kinases, and attenuated lipopolysaccharide-dependent mitogen-activated protein kinase p38 phosphorylation. CONCLUSIONS: PFD has lung allograft protective properties, and in addition to its known effects on T-cell biology, PFD immune-modulating activities encompass inhibitory effects on DC activation and function.

Indoleamine 2,3-dioxygenase and metabolites protect murine lung allografts and impair the calcium mobilization of T cells.

The enzyme indoleamine 2,3-dioxygenase (IDO) converts tryptophan into kynurenine metabolites that suppress effector T-cell function. In this study, we investigated IDO and its metabolite, 3-hydroxyanthranilic acid (3HAA), in regulating lung allograft rejection, using a murine orthotopic lung transplant model with a major mismatch (BALB/c donor and C57BL6 recipient). IDO was overexpressed in murine donor lungs, using an established nonviral (polyethylenimine carrier)-based gene transfer approach, whereas 3HAA was delivered daily via intraperitoneal injection. Increased IDO expression or its metabolite, 3HAA, resulted in a remarkable therapeutic effect with near normal lung function and little acute rejection, approximately A1, compared with A3 in untreated allografts (grading based on International Society for Heart and Lung Transplantation guidelines). We found that a high IDO environment for 7 days in lung allografts resulted in impaired T-cell activation, the production of multiple effector cytokines (IL-2, IL-4, IL-5, IL-6, IFN-γ, TNF-α, IL-12, and IL-13), and the generation of effector memory T cells (CD62L(lo)CD44(hi) phenotype). In isolated murine splenocytes, we observed that IDO/3HAA impaired T-cell receptor (TCR)-mediated T-cell activation, and more importantly, a decrease of intracellular calcium, phospholipase C-γ1 phosphorylation, and mitochondrial mass was evident. This work further illustrates the potential role of a high IDO environment in lung transplantation, and that the high IDO environment directly impairs TCR activation via the disruption of calcium signaling.

Transient modification within a pool of CD4 T cells in the maternal spleen.

Classic models suggest maternal tolerance is dependent on regulation of fetal antigen-specific T cell responses. We hypothesize that factors unique to a particular fetal antigen-specific T cell, rather than the state of pregnancy per se, are important determinants of T cell fate during pregnancy. To investigate the fate of fetal antigen-specific CD4 T cells in the systemic circulation, we examined spleen cells in a CD4 T cell receptor transgenic mouse specific for the male antigen H-Y. We observed a transient decrease in CD4(+) Vß6(+) cell numbers and, due to transient internalization of CD4, an increase in CD4(-) Vß6(+) T cells. Antigen-specific in vitro responsiveness was not depressed by pregnancy. These data suggest that pregnancy supports fluidity in this particular CD4 T cell pool that may, in turn, help to meet competing requirements of maternal immune responsiveness and fetal tolerance.

The effect of risedronate treatment on serum osteoprotegerin and bone marker levels in postmenopausal women with osteoporosis.

BACKGROUND: To evaluate the effect of risedronate treatment on osteoprotegerin (OPG), C-terminal cross-linking telopeptide of type 1 collagen (CTX), osteocalcin (OC), and deoxypyridinoline (DPD). METHODS: Eighty postmenopausal osteoporotic patients were randomized into two groups. In first group, patients received 35?mg of risedronate once a week and calcium with vitamin D per day. In second group, patients received only calcium with vitamin D per day. Bone turnover markers were measured at baseline, 1st, 3rd and 6th month. RESULTS: OPG levels were significantly reduced at 1st and 6th month of treatment in both groups, but no statistically significant difference was detected between groups. In the group treated with risedronate, difference in CTX level was observed at 3rd month of treatment, while a difference in DPD and OC levels were observed at 6th month of treatment. The baseline OPG levels correlated with age, menopause duration, and CTX levels. There was no correlation between OPG levels and the levels of the other markers during treatment. CONCLUSION: The present study showed that using risedronate in treatment of postmenopausal osteoporosis causes no specific changes in OPG levels; therefore, in contrast to some of the studies in the literature OPG may not be useful marker in monitoring of bisphosphonate.

Pirfenidone inhibits T-cell activation, proliferation, cytokine and chemokine production, and host alloresponses.

BACKGROUND: We previously showed that pirfenidone, an anti-fibrotic agent, reduces lung allograft injury or rejection. In this study, we tested the hypothesis that pirfenidone has immune modulating activities and evaluated its effects on the function of T-cell subsets, which play important roles in allograft rejection. METHOD: We first evaluated whether pirfenidone alters T-cell proliferation and cytokine release in response to T-cell receptor (TCR) activation, and whether pirfenidone alters regulatory T cells (CD4CD25) suppressive effects using an in vitro assay. Additionally, pirfenidone effects on alloantigen-induced T-cell proliferation in vivo were assessed by adoptive transfer of carboxyfluorescein diacetate succinimidyl ester-labeled T cells across a parent->F1 major histocompatibility complex mismatch, as well as using a murine heterotopic cardiac allograft model (BALB/c->C57BL/6). RESULTS: Pirfenidone was found to inhibit the responder frequency of TCR-stimulated CD4 cell total proliferation in vitro and in vivo, whereas both CD4 and CD8 proliferation index were reduced by pirfenidone. Additionally, pirfenidone inhibited TCR-induced production of multiple pro-inflammatory cytokines and chemokines. Interestingly, there was no change on transforming growth factor-beta production by purified T cells, and pirfenidone had no effect on the suppressive properties of naturally occurring regulatory T cells. Pirfenidone alone showed a small but significant (P<0.05) effect on the in vivo allogeneic response, whereas the combination of pirfenidone and low dose rapamycin had more remarkable effect in reducing the alloantigen response with prolonged graft survival. CONCLUSION: Pirfenidone may be an important new agent in transplantation, with particular relevance to combating chronic rejection by inhibiting both fibroproliferative and alloimmune responses.

Reduced cytotoxic function of effector CD8+ T cells is responsible for indoleamine 2,3-dioxygenase-dependent immune suppression.

Indoleamine 2,3-dioxygenase (IDO), a potent immunosuppressive enzyme, contributes to tumoral escape, immune tolerance, and protection against allograft injury. In this paper, we report that inhibition of CD8(+) T cell-mediated cytotoxic function is an important mechanism behind IDO's immune-modulating property. The experimental rat lung allograft proved attractive for evaluating effector CD8(+) T cells. Enhanced IDO activity achieved by using a lung-tissue-targeted nonviral human IDO gene transfer approach reduced, but did not eliminate, infiltrating CD8(+) T cells. Although CD8(+) T cells existed in the IDO-high lung allografts, CD8(+) T cells remained viable and could proliferate for an extended period. However, cells lost their ability to attack allogeneic donor lung cells in vivo and allogeneic target cells in vitro. The impaired cytotoxic function seen in the IDO-treated CD8(+) T cells was accompanied by defects in production of granule cytotoxic proteins, including perforin and granzyme A and B. Furthermore, we discovered that IDO leads to an impaired bioenergetic condition in active CD8(+) T cells via selective inhibition of complex I in the mitochondrial electron transfer chain. These intriguing findings provide a base for establishing a novel mode of IDO's immune-suppressing action. Additionally, donor lung IDO delivery, a direct and/or leukocyte passenger effect, impaired CD8(+) effector cell function.

Pregnancy alters the proliferation and apoptosis of mouse splenic erythroid lineage cells and leukocytes.

Pregnancy induces dynamic changes in the maternal environment that include reversible modifications in response to systemic mediators and local signals. The spleen can be used to determine the effects of pregnancy on multiple cellular populations, including those of the erythroid lineage and the immune system. Current evidence suggests that the transient increase in the size of the spleen during pregnancy is due to the expansion of erythroid precursors. However, it is unclear what factors contribute to this increase. Moreover, the additional erythroid cells may compete with neighboring leukocytes for growth factors or space, and this may in turn alter the function of these populations. Therefore, we assessed proliferation and apoptosis throughout gestation using in vivo bromodeoxyuridine incorporation and the TUNEL assay, respectively. Here, we show that erythroid-lineage TER-119(+) cells expanded significantly in midgestation because of enhanced proliferation and diminished apoptosis. This correlated with increased expression of the erythropoietin receptor (Epor) and decreased expression of the death receptor Fas, respectively. Leukocytes demonstrated population-specific responses. Natural killer cells proliferated in early pregnancy. Both lymphocytes and CD11B(+) cells underwent enhanced proliferation during midgestation. In contrast, neutrophils exhibited augmented proliferation throughout pregnancy. These subset-specific alterations in proliferation and death in the spleen suggest that complex regulation of population dynamics exists during pregnancy.

Resistance to lipopolysaccharide-induced preterm delivery mediated by regulatory T cell function in mice.

Intrauterine or intraperitoneal administration of lipopolysaccharide (LPS) into normal mice at midgestation induces preterm delivery (PTD) within 24 h through a mechanism dependent on Toll-like receptor signaling and expression of inflammatory cytokines. The exact participants in the cellular network involved in PTD are not known. Although the activities of innate immune cells are thought to be important, the extent to which this process depends on T and B cells has yet to be examined. Mice deficient in T and B cells due to genetic deficiency in the recombination activating gene 1 (Rag1(-/-)) were given LPS intraperitoneally on Day 15 of gestation and found to be susceptible to LPS-induced PTD. This was found to involve many of the inflammatory mediators reported as important in normal mice. Moreover, at a low dose (3 microg), pregnant Rag1(-/-) mice were found to be more susceptible to PTD than a cohort of normal mice on the same genetic background. This increased susceptibility was partially reversed by transfer, on Day 10 of gestation, of whole lymphocytes or purified CD4(+) T cells. Transfer of purified CD4(+) T cells to Rag1(-/-) mice resulted in a uterine draining node population of FOXP3(+) cells, suggesting that these cells may contribute to resistance to LPS-induced PTD. Overall, the data suggest that, although T and B lymphocytes are not critical positive regulators of LPS-induced PTD, CD4(+) T cells play a protective and regulatory role, and thus could be a target for preventive or therapeutic manipulation.

Dendritic cells: a family portrait at mid-gestation.

Recent advances in our understanding of dendritic cells (DCs) and their role in tolerance and immunity has fuelled study of their normal development and function within the reproductive tract. The common hypothesis that pregnancy is a state of immune suppression or deviation now includes the idea that alterations in DC phenotype and function are critical for maternal tolerance. We chose to study DCs in the uterus and lymphoid tissue in non-pregnant and pregnant mice at mid-gestation to understand what DC-related factors may be involved in premature birth. We used a mouse model where the mother's immune system has been shown to respond to the male antigen H-Y. Observed differences among DCs in the uterus, uterine draining nodes and spleen, even in non-pregnant mice, suggest the existence of a specialized uterus-specific subset of DCs. We further found that, amongst CD45(+) CD11c(+) cells in the uterus and peripheral lymphoid tissue of pregnant mice, expression of major histocompatibility complex class II (MHC II) and costimulatory molecules (i.e. CD80) was similar to that in the non-pregnant state. Moreover, there was no pregnancy-related decrease in the proportion of CD11c(+) cells in the uterus or in the uterine node that were CD11b(-) CD8(+). Pregnancy increased the CD11b(+) subsets and the expression of chemokine (C-C motif) ligand 6 (CCL6) in DCs of the uterine draining nodes. Finally, DC subsets showed variable expression, with respect to tissue and pregnancy, of the cytokine interleukin-15, which is important in lymphoid cell homeostasis. For DCs, pregnancy is not a state of immune paralysis, but of dynamic developmental change.