BACKGROUND: Liver cancer, a common malignancy within the digestive system, presents with a particularly grim prognosis. Within the immune microenvironment, the role of natural killer (NK) cells in liver cancer remains unclear.
METHODS: We sourced data on clinical parameters and gene expressions for liver cancer patients from The Cancer Genome Atlas Program database and carried out all analyses using R software and its relevant codes.
RESULTS: In our research, we delved into the genes intertwined with NK cells in hepatocellular carcinoma (HCC). Leveraging the QUANTISEQ and MCPCOUNTER algorithms to quantify NK cells, we spotlighted genes vital to the recruitment of NK cells. Among these genes, GDE1, WDFY3, DNAJB14, PKD2, DGAT2, SGMS2 and MKNK2 showed a strong correlation with patient outcomes. We also mapped out the single-cell expression trajectories of these genes within the HCC milieu. From our findings, SGMS2 emerged as a key gene warranting further scrutiny. Our in-depth analysis of SGMS2 shed light on its influence over specific biological pathways, its contribution to the immune landscape and its role in genomic instability within HCC. Drawing from this, we formulated a predictive model rooted in SGMS2-associated genes. This model showcased remarkable precision across both training and validation cohorts.
CONCLUSIONS: Overall, our investigation underscored the profound implications of SGMS2, a gene pivotal to NK cell infiltration, in the landscape of HCC, thereby positioning it as a potential linchpin in oncological strategies.

Aberrant biofunction of circular RNAs (circRNAs) is potently implicated in keloid formation. However, their roles have been underinvestigated. Recent evidence has demonstrated the pro-tumor role of circ_0000129 in cancers, and yet its role in keloid remains elusive.
RT-qPCR analysis and or western blotting of miR-485-3p, circ_0000129, and SGMS2 in keloid tissues and keloid fibroblasts was implemented. CCK8, EdU, scratch wound healing, and Transwell migration assays were perfomed to determine the keloid fibroblast proliferation and migration. Luciferase reporter and RIP assays were adopted to analyze the interaction among circ_0000129, miR-485-3p and SGMS2.
In keloid tissues and keloid fibroblasts, circ_0000129 and SGMS2 were amplified, although miR-485-3p expression was downregulated. Furthermore, siRNAs-targeting endogenous circ_0000129 resulted in proliferation and migration defect of keloid fibroblasts. MiR-485-3p was simultaneously recognized by circ_0000129 and SGMS2 3\'UTR. Rescued functional assays also illustrated that miR-485-3p loss was beneficial to the proliferation and migration of keloid fibroblasts, and these promoting changes were nullified by accompanied silence circ_0000129 or SGMS2.
Circ_0000129 sponges miR-485-3p and releases expression of SGMS2 from the miR-485-3p suppression, promoting migration and proliferation of keloid fibroblasts, suggesting targeting circ_0000129/miR-485-3p/SGMS2 might be a promising strategy against keloid fibroblasts.
All data generated or analyzed during this study are included in this article.

BACKGROUND: With increasing incidence and mortality, colorectal cancer (CRC) seriously endangers human health. LARP6, a member of La-related protein (LARP) family, is a RNA binding protein and probably associates with CRC progression, but its specific roles and mechanisms in CRC still remain unknown.
METHODS: Quantitative real-time PCR (qPCR), western blot, and immunohistochemistry were employed to examine LARP6 expression in CRC tissues. Using the stable LARP6 overexpression or interference CRC cell lines, the effect of LARP6 on CRC progression were evaluated. High-throughput RNA immunoprecipitation sequencing (RIP-seq) and a series of relevant experiments were conducted to explain how LARP6 functions. SPSS software was used for statistical analysis.
RESULTS: In this study, we found that LARP6 expression is downregulated in CRC and correlates with patients\' overall survival and relapse-free survival. Furthermore, altered LARP6 expression influences CRC cells invasion and metastasis. Mechanically, we discovered that LARP6 bind ZNF267 mRNA and regulated its stability and translation. LARP6 inhibited expression of SGMS2, a downstream target of ZNF267, resulting in ceramide and sphingomyelin imbalance in CRC cells. Interestingly, LARP6 also enhances autophagy activity of CRC cells, and the effect was at least partially determined by the inhibition of SGMS2-mediated sphingomyelin synthesis.
CONCLUSIONS: Our study showed how LARP6/ZNF267/SGMS2 axis influence CRC progression, which contributes to further understanding of the molecular mechanisms underlying CRC development.

Calvarial Doughnut Lesions with Bone Fragility (CDL) is an autosomal dominant genetic disease, characterized by low bone mineral density, multiple fractures starting in childhood, and sclerotic doughnut-shaped lesions in the cranial bones. Aubé and colleagues described in 1988 a French-Canadian family of 12 affected members who had a clinical diagnosis of doughnut lesions of the skull, with pathological fractures, osteopenia, \"bone in bone\" in the vertebral bodies and squaring of metatarsal and metacarpal bones. Herein we study new members of this family. Sequential genetic testing identified a nonsense variant c.148C>T, p. Arg50⁎ in SGMS2 previously reported in other families. SGMS2 encodes Sphingomyelin Synthase 2, which produces Sphingomyelin (SM), a major lipid component of the plasma membrane that plays a role in bone mineralization. The nonsense variant is associated with milder phenotype. The proband presents with bone in bone vertebral appearance that had been defined uniquely in the first cases described in the same family. The proband\'s son was identified to carry the same variant, which makes him the sixth generation with the diagnosis of CDL. We also report that the same pathogenic variant was identified in another previously described family, from France. These reports further confirm the genetic basis of CDL, the recurrence of the same variant (p.Arg50*) in individuals of the same ancestry, and the variable penetrance of some of the clinical findings.

Esophageal squamous cell carcinoma (ESCC) is kind of common and aggressive malignant tumors with high incidence and mortality all over the world. Accumulating studies have reported that long non-coding RNAs (lncRNAs) can play a vital regulatory role in human cancers. THAP9 antisense RNA 1 (THAP9-AS1) has been identified as an oncogene in several cancers. But its role in ESCC remains to be studied. In our research, THAP9-AS1 expression in ESCC cell lines was analyzed by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, migration, invasion and apoptosis as well as EMT process were analyzed by 5-Ethynyl-2\'-deoxyuridine ( EdU), Transwell, Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling (TUNEL) and western blot experiments. The interplay of THAP9-AS1, miR-335-5p and sphingomyelin synthase 2 (SGMS2) was analyzed by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. We discovered that THAP9-AS1 was highly expressed in ESCC cell lines and that the knockdown of THAP9-AS1 inhibited proliferation, migration, and invasion as well as EMT of ECSS cells but enhanced cell apoptosis. Furthermore, miR-335-5p was proved to be sponged by THAP9-AS1 and its up-regulation could repress ESCC progression. Additionally, SGMS2 was verified to be the target gene of miR-335-5p. In rescue assay, SGMS2 overexpression could offset the suppressive role of THAP9-AS1 depletion on ESCC progression. In short, THAP9-AS1 accelerated cell growth of ESCC through sponging miR-335-5p to regulate SGMS2.

Osteogenesis imperfecta (OI) and other decreased bone density disorders comprise a heterogeneous group of heritable diseases with skeletal fragility. Recently, it was discovered that mutations in SGMS2, encoding sphingomyelin synthetase 2, result in aberrant sphingomyelin metabolism and lead to a novel form of OI termed osteoporosis with calvarial doughnut lesions (OP-CDL) with moderate to severe skeletal fragility and variable cranial hyperostotic lesions. This study describes a Japanese family with the skeletal phenotype of OP-CDL. The affected individuals have moderately severe, childhood-onset skeletal fragility with multiple long-bone fractures, scoliosis and bone deformities. In addition, they exhibit multiple CDLs or calvarial bumps with central radiolucency and peripheral radiopacity. However, SGMS2 sequencing was normal. Instead, whole-exome sequencing identified a novel IFITM5 missense mutation c.143A>G (p.N48S) (classified as a VUS by ACMG). IFITM5 encodes an osteoblast-restricted protein BRIL and a recurrent c.-14C>T mutation in its 5\' UTR region results in OI type V, a distinctive subtype of OI associated with hyperplastic callus formation and ossification of the interosseous membranes. The patients described here have a phenotype clearly different from OI type V and with hyperostotic cranial lesions, feature previously unreported in association with IFITM5. Our findings expand the genetic spectrum of OP-CDL, indicate diverse phenotypic consequences of pathogenic IFITM5 variants, and imply an important role for BRIL in cranial skeletogenesis.

Heterozygous mutations in the gene encoding the sphingomyelin synthase 2, SGMS2, have recently been linked to childhood-onset osteoporosis and skeletal dysplasia. One nonsense variant at position c.148C>T (p.Arg50*) has been associated with mild bone fragility with or without cranial sclerosis. Here we assessed the effect of the SGMS2 p.Arg50* variant in two unrelated probands with childhood-onset osteoporosis and their unaffected family members. We found that the p.Arg50* variant was associated with phenotypic variability, ranging from absence of a bone phenotype to severe vertebral compression fractures and low lumbar spine areal bone mineral density (BMD) as measured by dual energy x-ray absorptiometry. Peripheral quantitative computed tomography of the radius and tibia in the two probands revealed low cortical volumetric BMD and reduced cortical thickness. In addition, both probands were obese and suffered from muscle function deficits compared to sex- and age-matched controls. Long-term bisphosphonate treatment was associated with reshaping of previously compressed vertebral bodies.

The obligate intracellular bacterium Chlamydia trachomatis proliferates in the membranous compartment inclusion formed in host cells. The host ceramide transport protein CERT delivers ceramide from the endoplasmic reticulum to the Golgi complex for the synthesis of sphingomyelin (SM). Chlamydia trachomatis has been suggested to employ CERT to produce SM in the inclusion by host SM synthases (SMSs). Here, we found that C. trachomatis proliferates and produces infective progeny even in SMS1 and SMS2 double-knockout HeLa cells, but not in the SMS1/SMS2/CERT triple-knockout cells. Interestingly, infected cells convert ceramide to SM without host SMSs. These results suggest that C. trachomatis-infected cells can convert ceramide to SM without host SMSs after CERT-mediated transfer of ceramide to the inclusions.

OBJECTIVE: The pathogenesis of alcohol-induced liver disease (ALD) is poorly understood. Here, we examined the role of acid sphingomyelinase (ASMase) in alcohol induced hepatic endoplasmic reticulum (ER) stress, a key mechanism of ALD.
METHODS: We examined ER stress, lipogenesis, hyperhomocysteinemia, mitochondrial cholesterol (mChol) trafficking and susceptibility to LPS and concanavalin-A in ASMase(-)(/-) mice fed alcohol.
RESULTS: Alcohol feeding increased SREBP-1c, DGAT-2, and FAS mRNA in ASMase(+/+) but not in ASMase(-/-) mice. Compared to ASMase(+/+) mice, ASMase(-/-) mice exhibited decreased expression of ER stress markers induced by alcohol, but the level of tunicamycin-mediated upregulation of ER stress markers and steatosis was similar in both types of mice. The increase in homocysteine levels induced by alcohol feeding was comparable in both ASMase(+/+) and ASMase(-/-) mice. Exogenous ASMase, but not neutral SMase, induced ER stress by perturbing ER Ca(2+) homeostasis. Moreover, alcohol-induced mChol loading and StARD1 overexpression were blunted in ASMase(-/-) mice. Tunicamycin upregulated StARD1 expression and this outcome was abrogated by tauroursodeoxycholic acid. Alcohol-induced liver injury and sensitization to LPS and concanavalin-A were prevented in ASMase(-/-) mice. These effects were reproduced in alcohol-fed TNFR1/R2(-/-) mice. Moreover, ASMase does not impair hepatic regeneration following partial hepatectomy. Of relevance, liver samples from patients with alcoholic hepatitis exhibited increased expression of ASMase, StARD1, and ER stress markers.
CONCLUSIONS: Our data indicate that ASMase is critical for alcohol-induced ER stress, and provide a rationale for further clinical investigation in ALD.